MIPS: Fix typos

Fix typos, most reported by "codespell arch/mips". Only touches comments,
no code changes.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-mips@vger.kernel.org
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: KVM: Fix NULL pointer dereference

After commit 45c7e8af4a5e3f0bea4ac209 ("MIPS: Remove KVM_TE support") we
get a NULL pointer dereference when creating a KVM guest:

[ 146.243409] Starting KVM with MIPS VZ extensions
[ 149.849151] CPU 3 Unable to handle kernel paging request at virtual address 0000000000000300, epc == ffffffffc06356ec, ra == ffffffffc063568c
[ 149.849177] Oops[#1]:
[ 149.849182] CPU: 3 PID: 2265 Comm: qemu-system-mip Not tainted 6.4.0-rc3+ #1671
[ 149.849188] Hardware name: THTF CX TL630 Series/THTF-LS3A4000-7A1000-ML4A, BIOS KL4.1F.TF.D.166.201225.R 12/25/2020
[ 149.849192] $ 0 : 0000000000000000 000000007400cce0 0000000000400004 ffffffff8119c740
[ 149.849209] $ 4 : 000000007400cce1 000000007400cce1 0000000000000000 0000000000000000
[ 149.849221] $ 8 : 000000240058bb36 ffffffff81421ac0 0000000000000000 0000000000400dc0
[ 149.849233] $12 : 9800000102a07cc8 ffffffff80e40e38 0000000000000001 0000000000400dc0
[ 149.849245] $16 : 0000000000000000 9800000106cd0000 9800000106cd0000 9800000100cce000
[ 149.849257] $20 : ffffffffc0632b28 ffffffffc05b31b0 9800000100ccca00 0000000000400000
[ 149.849269] $24 : 9800000106cd09ce ffffffff802f69d0
[ 149.849281] $28 : 9800000102a04000 9800000102a07cd0 98000001106a8000 ffffffffc063568c
[ 149.849293] Hi : 00000335b2111e66
[ 149.849295] Lo : 6668d90061ae0ae9
[ 149.849298] epc : ffffffffc06356ec kvm_vz_vcpu_setup+0xc4/0x328 [kvm]
[ 149.849324] ra : ffffffffc063568c kvm_vz_vcpu_setup+0x64/0x328 [kvm]
[ 149.849336] Status: 7400cce3 KX SX UX KERNEL EXL IE
[ 149.849351] Cause : 1000000c (ExcCode 03)
[ 149.849354] BadVA : 0000000000000300
[ 149.849357] PrId : 0014c004 (ICT Loongson-3)
[ 149.849360] Modules linked in: kvm nfnetlink_queue nfnetlink_log nfnetlink fuse sha256_generic libsha256 cfg80211 rfkill binfmt_misc vfat fat snd_hda_codec_hdmi input_leds led_class snd_hda_intel snd_intel_dspcfg snd_hda_codec snd_hda_core snd_pcm snd_timer snd serio_raw xhci_pci radeon drm_suballoc_helper drm_display_helper xhci_hcd ip_tables x_tables
[ 149.849432] Process qemu-system-mip (pid: 2265, threadinfo=00000000ae2982d2, task=0000000038e09ad4, tls=000000ffeba16030)
[ 149.849439] Stack : 9800000000000003 9800000100ccca00 9800000100ccc000 ffffffffc062cef4
[ 149.849453] 9800000102a07d18 c89b63a7ab338e00 0000000000000000 ffffffff811a0000
[ 149.849465] 0000000000000000 9800000106cd0000 ffffffff80e59938 98000001106a8920
[ 149.849476] ffffffff80e57f30 ffffffffc062854c ffffffff811a0000 9800000102bf4240
[ 149.849488] ffffffffc05b0000 ffffffff80e3a798 000000ff78000000 000000ff78000010
[ 149.849500] 0000000000000255 98000001021f7de0 98000001023f0078 ffffffff81434000
[ 149.849511] 0000000000000000 0000000000000000 9800000102ae0000 980000025e92ae28
[ 149.849523] 0000000000000000 c89b63a7ab338e00 0000000000000001 ffffffff8119dce0
[ 149.849535] 000000ff78000010 ffffffff804f3d3c 9800000102a07eb0 0000000000000255
[ 149.849546] 0000000000000000 ffffffff8049460c 000000ff78000010 0000000000000255
[ 149.849558] ...
[ 149.849565] Call Trace:
[ 149.849567] [<ffffffffc06356ec>] kvm_vz_vcpu_setup+0xc4/0x328 [kvm]
[ 149.849586] [<ffffffffc062cef4>] kvm_arch_vcpu_create+0x184/0x228 [kvm]
[ 149.849605] [<ffffffffc062854c>] kvm_vm_ioctl+0x64c/0xf28 [kvm]
[ 149.849623] [<ffffffff805209c0>] sys_ioctl+0xc8/0x118
[ 149.849631] [<ffffffff80219eb0>] syscall_common+0x34/0x58

The root cause is the deletion of kvm_mips_commpage_init() leaves vcpu
->arch.cop0 NULL. So fix it by making cop0 from a pointer to an embedded
object.

Fixes: 45c7e8af4a5e3f0bea4ac209 ("MIPS: Remove KVM_TE support")
Cc: stable@vger.kernel.org
Reported-by: Yu Zhao <yuzhao@google.com>
Suggested-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

KVM: remove KVM_REQ_UNHALT

KVM_REQ_UNHALT is now unnecessary because it is replaced by the return
value of kvm_vcpu_block/kvm_vcpu_halt. Remove it.

No functional change intended.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Message-Id: <20220921003201.1441511-13-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: mips, x86: do not rely on KVM_REQ_UNHALT

KVM_REQ_UNHALT is a weird request that simply reports the value of
kvm_arch_vcpu_runnable() on exit from kvm_vcpu_halt(). Only
MIPS and x86 are looking at it, the others just clear it. Check
the state of the vCPU directly so that the request is handled
as a nop on all architectures.

No functional change intended, except for corner cases where an
event arrive immediately after a signal become pending or after
another similar host-side event.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220921003201.1441511-12-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: Rename kvm_vcpu_block() => kvm_vcpu_halt()

Rename kvm_vcpu_block() to kvm_vcpu_halt() in preparation for splitting
the actual "block" sequences into a separate helper (to be named
kvm_vcpu_block()). x86 will use the standalone block-only path to handle
non-halt cases where the vCPU is not runnable.

Rename block_ns to halt_ns to match the new function name.

No functional change intended.

Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211009021236.4122790-14-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: Remove KVM_TE support

After removal of the guest part of KVM TE (trap and emulate), also remove
the host part.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: KVM: Convert a fallthrough comment to fallthrough

There is a fallthrough comment being forgotten,
GCC complains about it:

arch/mips/kvm/emulate.c: In function kvm_mips_emulate_load:
arch/mips/kvm/emulate.c:1936:21: error: this statement may fall through
1936 | vcpu->mmio_needed = 1; /* unsigned */
| ~~~~~~~~~~~~~~~~~~^~~
arch/mips/kvm/emulate.c:1939:2: note: here
1939 | case lw_op:

Just fix it.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Reviewed-by: Huacai Chen <chenhc@lemote.com>
Message-Id: <20200810011749.3211128-1-jiaxun.yang@flygoat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Fix build error caused by 'kvm_run' cleanup

Commit c34b26b98caca48ec9ee9 ("KVM: MIPS: clean up redundant 'kvm_run'
parameters") remove the 'kvm_run' parameter in kvm_mips_complete_mmio_
load(), but forget to update all callers.

Fixes: c34b26b98caca48ec9ee9 ("KVM: MIPS: clean up redundant 'kvm_run' parameters")
Reported-by: kernel test robot <lkp@intel.com>
Cc: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Message-Id: <1595154207-9787-1-git-send-email-chenhc@lemote.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: MIPS: Fix build errors for 32bit kernel

Commit dc6d95b153e78ed70b1b2c04a ("KVM: MIPS: Add more MMIO load/store
instructions emulation") introduced some 64bit load/store instructions
emulation which are unavailable on 32bit platform, and it causes build
errors:

arch/mips/kvm/emulate.c: In function 'kvm_mips_emulate_store':
arch/mips/kvm/emulate.c:1734:6: error: right shift count >= width of type [-Werror]
((vcpu->arch.gprs[rt] >> 56) & 0xff);
^
arch/mips/kvm/emulate.c:1738:6: error: right shift count >= width of type [-Werror]
((vcpu->arch.gprs[rt] >> 48) & 0xffff);
^
arch/mips/kvm/emulate.c:1742:6: error: right shift count >= width of type [-Werror]
((vcpu->arch.gprs[rt] >> 40) & 0xffffff);
^
arch/mips/kvm/emulate.c:1746:6: error: right shift count >= width of type [-Werror]
((vcpu->arch.gprs[rt] >> 32) & 0xffffffff);
^
arch/mips/kvm/emulate.c:1796:6: error: left shift count >= width of type [-Werror]
(vcpu->arch.gprs[rt] << 32);
^
arch/mips/kvm/emulate.c:1800:6: error: left shift count >= width of type [-Werror]
(vcpu->arch.gprs[rt] << 40);
^
arch/mips/kvm/emulate.c:1804:6: error: left shift count >= width of type [-Werror]
(vcpu->arch.gprs[rt] << 48);
^
arch/mips/kvm/emulate.c:1808:6: error: left shift count >= width of type [-Werror]
(vcpu->arch.gprs[rt] << 56);
^
cc1: all warnings being treated as errors
make[3]: *** [arch/mips/kvm/emulate.o] Error 1

So, use #if defined(CONFIG_64BIT) && defined(CONFIG_KVM_MIPS_VZ) to
guard the 64bit load/store instructions emulation.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: dc6d95b153e78ed70b1b2c04a ("KVM: MIPS: Add more MMIO load/store instructions emulation")
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Message-Id: <1594365797-536-1-git-send-email-chenhc@lemote.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: MIPS: clean up redundant 'kvm_run' parameters

In the current kvm version, 'kvm_run' has been included in the 'kvm_vcpu'
structure. For historical reasons, many kvm-related function parameters
retain the 'kvm_run' and 'kvm_vcpu' parameters at the same time. This
patch does a unified cleanup of these remaining redundant parameters.

Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Reviewed-by: Huacai Chen <chenhc@lemote.com>
Message-Id: <20200623131418.31473-5-tianjia.zhang@linux.alibaba.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: MIPS: fix spelling mistake "Exteneded" -> "Extended"

There is a spelling mistake in a couple of kvm_err messages. Fix them.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Message-Id: <20200615082636.7004-1-colin.king@canonical.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: MIPS: Add more MMIO load/store instructions emulation

This patch add more MMIO load/store instructions emulation, which can
be observed in QXL and some other device drivers:

1, LWL, LWR, LDW, LDR, SWL, SWR, SDL and SDR for all MIPS;
2, GSLBX, GSLHX, GSLWX, GSLDX, GSSBX, GSSHX, GSSWX and GSSDX for
Loongson-3.

Reviewed-by: Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Co-developed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Message-Id: <1590220602-3547-14-git-send-email-chenhc@lemote.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: MIPS: Add Loongson-3 Virtual IPI interrupt support

This patch add Loongson-3 Virtual IPI interrupt support in the kernel.
The current implementation of IPI emulation in QEMU is based on GIC for
MIPS, but Loongson-3 doesn't use GIC. Furthermore, IPI emulation in QEMU
is too expensive for performance (because of too many context switches
between Host and Guest). With current solution, the IPI delay may even
cause RCU stall warnings in a multi-core Guest. So, we design a faster
solution that emulate IPI interrupt in kernel (only used by Loongson-3
now).

Reviewed-by: Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Co-developed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Message-Id: <1590220602-3547-11-git-send-email-chenhc@lemote.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: MIPS/Emulate: Remove unneeded semicolon

Fixes coccicheck warnings:

arch/mips/kvm/emulate.c:1793:3-4: Unneeded semicolon
arch/mips/kvm/emulate.c:1968:3-4: Unneeded semicolon

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Reviewed-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Use fallthrough for arch/mips

Convert the various /* fallthrough */ comments to the pseudo-keyword
fallthrough;

Done via script:
https://lore.kernel.org/lkml/b56602fcf79f849e733e7b521bb0e17895d390fa.1582230379.git.joe@perches.com/

Signed-off-by: Liangliang Huang <huangll@lemote.com>
Reviewed-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Annotate fall-through in kvm/emulate.c

kvm_compute_return_epc contains a switch statement with an intentional
fall-through from a case handling jal (jump and link) instructions to
one handling j (jump) instructions. With -Wimplicit-fallthrough this
triggers a compile error (due to -Werror being enabled for arch/mips).

This can be reproduced using malta_kvm_defconfig.

Fix this by annotating the intentional fall-through.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org

MIPS: KVM: Use prandom_u32_max() to generate tlbwr index

Emulation of the tlbwr instruction, which writes a TLB entry to a random
index in the TLB, currently uses get_random_bytes() to generate a 4 byte
random number which we then mask to form the index. This is overkill in
a couple of ways:

- We don't need 4 bytes here since we mask the value to form a 6 bit
number anyway, so we waste /dev/random entropy generating 3 random
bytes that are unused.

- We don't need crypto-grade randomness here - the architecture spec
allows implementations to use any algorithm & merely encourages that
some pseudo-randomness be used rather than a simple counter. The
fast prandom_u32() function fits that criteria well.

So rather than using get_random_bytes() & consuming /dev/random entropy,
switch to using the faster prandom_u32_max() which provides what we need
here whilst also performing the masking/modulo for us.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Reported-by: George Spelvin <lkml@sdf.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@vger.kernel.org

MIPS: mm: Add set_cpu_context() for ASID assignments

When we gain MMID support we'll be storing MMIDs as atomic64_t values
and accessing them via atomic64_* functions. This necessitates that we
don't use cpu_context() as the left hand side of an assignment, ie. as a
modifiable lvalue. In preparation for this introduce a new
set_cpu_context() function & replace all assignments with cpu_context()
on their left hand side with an equivalent call to set_cpu_context().

To enforce that cpu_context() should not be used for assignments, we
rewrite it as a static inline function.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org

MIPS: mm: Remove redundant get_new_mmu_context() cpu argument

get_new_mmu_context() accepts a cpu argument, but implicitly assumes
that this is always equal to smp_processor_id() by operating on the
local CPU's TLB & icache.

Remove the cpu argument and have get_new_mmu_context() call
smp_processor_id() instead.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org

mm: remove include/linux/bootmem.h

Move remaining definitions and declarations from include/linux/bootmem.h
into include/linux/memblock.h and remove the redundant header.

The includes were replaced with the semantic patch below and then
semi-automated removal of duplicated '#include <linux/memblock.h>

@@
@@
- #include <linux/bootmem.h>
+ #include <linux/memblock.h>

[sfr@canb.auug.org.au: dma-direct: fix up for the removal of linux/bootmem.h]
Link: http://lkml.kernel.org/r/20181002185342.133d1680@canb.auug.org.au
[sfr@canb.auug.org.au: powerpc: fix up for removal of linux/bootmem.h]
Link: http://lkml.kernel.org/r/20181005161406.73ef8727@canb.auug.org.au
[sfr@canb.auug.org.au: x86/kaslr, ACPI/NUMA: fix for linux/bootmem.h removal]
Link: http://lkml.kernel.org/r/20181008190341.5e396491@canb.auug.org.au
Link: http://lkml.kernel.org/r/1536927045-23536-30-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

KVM: add kvm_{test,clear}_request to replace {test,clear}_bit

Users were expected to use kvm_check_request() for testing and clearing,
but request have expanded their use since then and some users want to
only test or do a faster clear.

Make sure that requests are not directly accessed with bit operations.

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: MIPS/Emulate: Properly implement TLBR for T&E

Properly implement emulation of the TLBR instruction for Trap & Emulate.
This instruction reads the TLB entry pointed at by the CP0_Index
register into the other TLB registers, which may have the side effect of
changing the current ASID. Therefore abstract the CP0_EntryHi and ASID
changing code into a common function in the process.

A comment indicated that Linux doesn't use TLBR, which is true during
normal use, however dumping of the TLB does use it (for example with the
relatively recent 'x' magic sysrq key), as does a wired TLB entries test
case in my KVM tests.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS/Emulate: Adapt T&E CACHE emulation for Octeon

Cache management is implemented separately for Cavium Octeon CPUs, so
r4k_blast_[id]cache aren't available. Instead for Octeon perform a local
icache flush using local_flush_icache_range(), and for other platforms
which don't use c-r4k.c use __flush_cache_all() / flush_icache_all().

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Daney <david.daney@cavium.com>
Cc: Andreas Herrmann <andreas.herrmann@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS/VZ: Support hardware guest timer

Transfer timer state to the VZ guest context (CP0_GTOffset & guest
CP0_Count) when entering guest mode, enabling direct guest access to it,
and transfer back to soft timer when saving guest register state.

This usually allows guest code to directly read CP0_Count (via MFC0 and
RDHWR) and read/write CP0_Compare, without trapping to the hypervisor
for it to emulate the guest timer. Writing to CP0_Count or CP0_Cause.DC
is much less common and still triggers a hypervisor GPSI exception, in
which case the timer state is transferred back to an hrtimer before
emulating the write.

We are careful to prevent small amounts of drift from building up due to
undeterministic time intervals between reading of the ktime and reading
of CP0_Count. Some drift is expected however, since the system
clocksource may use a different timer to the local CP0_Count timer used
by VZ. This is permitted to prevent guest CP0_Count from appearing to go
backwards.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS/Emulate: Drop CACHE emulation for VZ

Ifdef out the trap & emulate CACHE instruction emulation functions for
VZ. We will provide separate CACHE instruction emulation in vz.c, and we
need to avoid linker errors due to the use of T&E specific MMU helpers.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS/Emulate: Update CP0_Compare emulation for VZ

Update emulation of guest writes to CP0_Compare for VZ. There are two
main differences compared to trap & emulate:

- Writing to CP0_Compare in the VZ hardware guest context acks any
pending timer, clearing CP0_Cause.TI. If we don't want an ack to take
place we must carefully restore the TI bit if it was previously set.

- Even with guest timer access disabled in CP0_GuestCtl0.GT, if the
guest CP0_Count reaches the guest CP0_Compare the timer interrupt
will assert. To prevent this we must set CP0_GTOffset to move the
guest CP0_Count out of the way of the new guest CP0_Compare, either
before or after depending on whether it is a forwards or backwards
change.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS: Abstract guest CP0 register access for VZ

Abstract the MIPS KVM guest CP0 register access macros into inline
functions which are generated by macros. This allows them to be
generated differently for VZ, where they will usually need to access the
hardware guest CP0 context rather than the saved values in RAM.

Accessors for each individual register are generated using these macros:

- __BUILD_KVM_*_SW() for registers which are not present in the VZ
hardware guest context, so kvm_{read,write}_c0_guest_##name() will
access the saved value in RAM regardless of whether VZ is enabled.

- __BUILD_KVM_*_HW() for registers which are present in the VZ hardware
guest context, so kvm_{read,write}_c0_guest_##name() will access the
hardware register when VZ is enabled.

These build the underlying accessors using further macros:

- __BUILD_KVM_*_SAVED() builds e.g. kvm_{read,write}_sw_gc0_##name()
functions for accessing the saved versions of the registers in RAM.
This is used for implementing the common
kvm_{read,write}_c0_guest_##name() accessors with T&E where registers
are always stored in RAM, but are also available with VZ HW registers
to allow them to be accessed while saved.

- __BUILD_KVM_*_VZ() builds e.g. kvm_{read,write}_vz_gc0_##name()
functions for accessing the VZ hardware guest context registers
directly. This is used for implementing the common
kvm_{read,write}_c0_guest_##name() accessors with VZ.

- __BUILD_KVM_*_WRAP() builds wrappers with different names, which
allows the common kvm_{read,write}_c0_guest_##name() functions to be
implemented using the VZ accessors while still having the SAVED
accessors available too.

- __BUILD_KVM_SAVE_VZ() builds functions for saving and restoring VZ
hardware guest context register state to RAM, improving conciseness
of VZ context saving and restoring.

Similar macros exist for generating modifiers (set, clear, change),
either with a normal unlocked read/modify/write, or using atomic LL/SC
sequences.

These changes change the types of 32-bit registers to u32 instead of
unsigned long, which requires some changes to printk() functions in MIPS
KVM.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS: Init timer frequency from callback

Currently the software emulated timer is initialised to a frequency of
100MHz by kvm_mips_init_count(), but this isn't suitable for VZ where
the frequency of the guest timer matches that of the host.

Add a count_hz argument so the caller can specify the default frequency,
and move the call from kvm_arch_vcpu_create() to the implementation
specific vcpu_setup() callback, so that VZ can specify a different
frequency.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS/Emulate: Implement 64-bit MMIO emulation

Implement additional MMIO emulation for MIPS64, including 64-bit
loads/stores, and 32-bit unsigned loads. These are only exposed on
64-bit VZ hosts.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS/Emulate: De-duplicate MMIO emulation

Refactor MIPS KVM MMIO load/store emulation to reduce code duplication.
Each duplicate differed slightly anyway, and it will simplify adding
64-bit MMIO support for VZ.

kvm_mips_emulate_store() and kvm_mips_emulate_load() can now return
EMULATE_DO_MMIO (as possibly originally intended). We therefore stop
calling either of these from kvm_mips_emulate_inst(), which is now only
used by kvm_trap_emul_handle_cop_unusable() which is picky about return
values.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS: Implement HYPCALL emulation

Emulate the HYPCALL instruction added in the VZ ASE and used by the MIPS
paravirtualised guest support that is already merged. The new hypcall.c
handles arguments and the return value. No actual hypercalls are yet
supported, but this still allows us to safely step over hypercalls and
set an error code in the return value for forward compatibility.

Non-zero HYPCALL codes are not handled.

We also document the hypercall ABI which asm/kvm_para.h uses.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Andreas Herrmann <andreas.herrmann@caviumnetworks.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: linux-doc@vger.kernel.org

KVM: MIPS/T&E: Implement CP0_EBase register

The CP0_EBase register is a standard feature of MIPS32r2, so we should
always have been implementing it properly. However the register value
was ignored and wasn't exposed to userland.

Fix the emulation of exceptions and interrupts to use the value stored
in guest CP0_EBase, and fix the masks so that the top 3 bits (rather
than the standard 2) are fixed, so that it is always in the guest KSeg0
segment.

Also add CP0_EBASE to the KVM one_reg interface so it can be accessed by
userland, also allowing the CPU number field to be written (which isn't
permitted by the guest).

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS/T&E: Move CP0 register access into T&E

Access to various CP0 registers via the KVM register access API needs to
be implementation specific to allow restrictions to be made on changes,
for example when VZ guest registers aren't present, so move them all
into trap_emul.c in preparation for VZ.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS/T&E: Handle read only GPA in TLB mod

Rewrite TLB modified exception handling to handle read only GPA memory
regions, instead of unconditionally passing the exception to the guest.

If the guest TLB is not the cause of the exception we call into the
normal TLB fault handling depending on the memory segment, which will
soon attempt to remap the physical page to be writable (handling dirty
page tracking or copy on write in the process).

Failing that we fall back to treating it as MMIO, due to a read only
memory region. Once the capability is enabled, this will allow read only
memory regions (such as the Malta boot flash as emulated by QEMU) to
have writes treated as MMIO, while still allowing reads to run
untrapped.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS: Pass type of fault down to kvm_mips_map_page()

kvm_mips_map_page() will need to know whether the fault was due to a
read or a write in order to support dirty page tracking,
KVM_CAP_SYNC_MMU, and read only memory regions, so get that information
passed down to it via new bool write_fault arguments to various
functions.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS/Emulate: Use lockless GVA helpers for cache emulation

Use the lockless GVA helpers to implement the reading of guest
instructions for emulation. This will allow it to handle asynchronous
TLB flushes when they are implemented.

This is a little more complicated than the other two cases (get_inst()
and dynamic translation) due to the need to emulate the appropriate
guest TLB exception when the address isn't present or isn't valid in the
guest TLB.

Since there are several protected cache ops that may need to be
performed safely, this is abstracted by kvm_mips_guest_cache_op() which
is passed a protected cache op function pointer and takes care of the
lockless operation and fault handling / retry if the op should fail,
taking advantage of the new errors which the protected cache ops can now
return. This allows the existing advance fault handling which relied on
host TLB lookups to be removed, along with the now unused
kvm_mips_host_tlb_lookup(),

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS: Use CP0_BadInstr[P] for emulation

When exiting from the guest, store the values of the CP0_BadInstr and
CP0_BadInstrP registers if they exist, which contain the encodings of
the instructions which caused the last synchronous exception.

When the instruction is needed for emulation, kvm_get_badinstr() and
kvm_get_badinstrp() are used instead of calling kvm_get_inst() directly,
to decide whether to read the saved CP0_BadInstr/CP0_BadInstrP registers
(if they exist), or read the instruction from memory (if not).

The use of these registers should be more robust than using
kvm_get_inst(), as it actually gives the instruction encoding seen by
the hardware rather than relying on user accessors after the fact, which
can be fooled by incoherent icache or a racing code modification. It
will also work with VZ, where the guest virtual memory isn't directly
accessible by the host with user accessors.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS: Improve kvm_get_inst() error return

Currently kvm_get_inst() returns KVM_INVALID_INST in the event of a
fault reading the guest instruction. This has the rather arbitrary magic
value 0xdeadbeef. This API isn't very robust, and in fact 0xdeadbeef is
a valid MIPS64 instruction encoding, namely "ld t1,-16657(s5)".

Therefore change the kvm_get_inst() API to return 0 or -EFAULT, and to
return the instruction via a u32 *out argument. We can then drop the
KVM_INVALID_INST definition entirely.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS/MMU: Drop kvm_get_new_mmu_context()

MIPS KVM uses its own variation of get_new_mmu_context() which takes an
extra vcpu pointer (unused) and does exactly the same thing.

Switch to just using get_new_mmu_context() directly and drop KVM's
version of it as it doesn't really serve any purpose.

The nearby declarations of kvm_mips_alloc_new_mmu_context(),
kvm_mips_vcpu_load() and kvm_mips_vcpu_put() are also removed from
kvm_host.h, as no definitions or users exist.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS/Emulate: Drop redundant TLB flushes on exceptions

When exceptions are injected into the MIPS KVM guest, the whole host TLB
is flushed (except any entries in the guest KSeg0 range). This is
certainly not mandated by the architecture when exceptions are taken
(userland can't directly change TLB mappings anyway), and is a pretty
heavyweight operation:

- There may be hundreds of TLB entries especially when a 512 entry FTLB
is present. These are walked and read and conditionally invalidated,
so the TLBINV feature can't be used either.

- It'll indiscriminately wipe out entries belonging to other memory
spaces. A simple ASID regeneration would be much faster to perform,
although it'd wipe out the guest KSeg0 mappings too.

My suspicion is that this was simply to plaster over the fact that
kvm_mips_host_tlb_inv() incorrectly only invalidated TLB entries in the
ASID for guest usermode, and not the ASID for guest kernelmode.

Now that the recent commit "KVM: MIPS/TLB: Flush host TLB entry in
kernel ASID" fixes kvm_mips_host_tlb_inv() to flush TLB entries in the
kernelmode ASID when the guest TLB changes, lets drop these calls and
the otherwise unused kvm_mips_flush_host_tlb().

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS/Emulate: Fix CACHE emulation for EVA hosts

Use protected_writeback_dcache_line() instead of flush_dcache_line(),
and protected_flush_icache_line() instead of flush_icache_line(), so
that CACHEE (the EVA variant) is used on EVA host kernels.

Without this, guest floating point branch delay slot emulation via a
trampoline on the user stack fails on EVA host kernels due to failure of
the icache sync, resulting in the break instruction getting skipped and
execution from the stack.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS/MMU: Convert TLB mapped faults to page tables

Now that we have GVA page tables and an optimised TLB refill handler in
place, convert the handling of page faults in TLB mapped segment from
the guest to fill a single GVA page table entry and invalidate the TLB
entry, rather than filling a TLB entry pair directly.

Also remove the now unused kvm_mips_get_{kernel,user}_asid() functions
in mmu.c and kvm_mips_host_tlb_write() in tlb.c.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS/MMU: Invalidate stale GVA PTEs on TLBW

Implement invalidation of specific pairs of GVA page table entries in
one or both of the GVA page tables. This is used when existing mappings
are replaced in the guest TLB by emulated TLBWI/TLBWR instructions. Due
to the sharing of page tables in the host kernel range, we should be
careful not to allow host pages to be invalidated.

Add a helper kvm_mips_walk_pgd() which can be used when walking of
either GPA (future patches) or GVA page tables is needed, optionally
with allocation of page tables along the way when they don't exist.

GPA page table walking will need to be protected by the kvm->mmu_lock,
so we also add a small MMU page cache in each KVM VCPU, like that found
for other architectures but smaller. This allows enough pages to be
pre-allocated to handle a single fault without holding the lock,
allowing the helper to run with the lock held without having to handle
allocation failures.

Using the same mechanism for GVA allows the same code to be used, and
allows it to use the same cache of allocated pages if the GPA walk
didn't need to allocate any new tables.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS/MMU: Invalidate GVA PTs on ASID changes

Implement invalidation of large ranges of virtual addresses from GVA
page tables in response to a guest ASID change (immediately for guest
kernel page table, lazily for guest user page table).

We iterate through a range of page tables invalidating entries and
freeing fully invalidated tables. To minimise overhead the exact ranges
invalidated depends on the flags argument to kvm_mips_flush_gva_pt(),
which also allows it to be used in future KVM_CAP_SYNC_MMU patches in
response to GPA changes, which unlike guest TLB mapping changes affects
guest KSeg0 mappings.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS/TLB: Generalise host TLB invalidate to kernel ASID

Refactor kvm_mips_host_tlb_inv() to also be able to invalidate any
matching TLB entry in the kernel ASID rather than assuming only the TLB
entries in the user ASID can change. Two new bool user/kernel arguments
allow the caller to indicate whether the mapping should affect each of
the ASIDs for guest user/kernel mode.

- kvm_mips_invalidate_guest_tlb() (used by TLBWI/TLBWR emulation) can
now invalidate any corresponding TLB entry in both the kernel ASID
(guest kernel may have accessed any guest mapping), and the user ASID
if the entry being replaced is in guest USeg (where guest user may
also have accessed it).

- The tlbmod fault handler (and the KSeg0 / TLB mapped / commpage fault
handlers in later patches) can now invalidate the corresponding TLB
entry in whichever ASID is currently active, since only a single page
table will have been updated anyway.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS: Remove duplicated ASIDs from vcpu

The kvm_vcpu_arch structure contains both mm_structs for allocating MMU
contexts (primarily the ASID) but it also copies the resulting ASIDs
into guest_{user,kernel}_asid[] arrays which are referenced from uasm
generated code.

This duplication doesn't seem to serve any purpose, and it gets in the
way of generalising the ASID handling across guest kernel/user modes, so
lets just extract the ASID straight out of the mm_struct on demand, and
in fact there are convenient cpu_context() and cpu_asid() macros for
doing so.

To reduce the verbosity of this code we do also add kern_mm and user_mm
local variables where the kernel and user mm_structs are used.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS: Precalculate MMIO load resume PC

The advancing of the PC when completing an MMIO load is done before
re-entering the guest, i.e. before restoring the guest ASID. However if
the load is in a branch delay slot it may need to access guest code to
read the prior branch instruction. This isn't safe in TLB mapped code at
the moment, nor in the future when we'll access unmapped guest segments
using direct user accessors too, as it could read the branch from host
user memory instead.

Therefore calculate the resume PC in advance while we're still in the
right context and save it in the new vcpu->arch.io_pc (replacing the no
longer needed vcpu->arch.pending_load_cause), and restore it on MMIO
completion.

Fixes: e685c689f3a8 ("KVM/MIPS32: Privileged instruction/target branch emulation.")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: <stable@vger.kernel.org> # 3.10.x-
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: MIPS: Make ERET handle ERL before EXL

The ERET instruction to return from exception is used for returning from
exception level (Status.EXL) and error level (Status.ERL). If both bits
are set however we should be returning from ERL first, as ERL can
interrupt EXL, for example when an NMI is taken. KVM however checks EXL
first.

Fix the order of the checks to match the pseudocode in the instruction
set manual.

Fixes: e685c689f3a8 ("KVM/MIPS32: Privileged instruction/target branch emulation.")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: <stable@vger.kernel.org> # 3.10.x-
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: kvm: Audit and remove any unnecessary uses of module.h

Historically a lot of these existed because we did not have
a distinction between what was modular code and what was providing
support to modules via EXPORT_SYMBOL and friends. That changed
when we forked out support for the latter into the export.h file.

This means we should be able to reduce the usage of module.h
in code that is obj-y Makefile or bool Kconfig. In the case of
kvm where it is modular, we can extend that to also include files
that are building basic support functionality but not related
to loading or registering the final module; such files also have
no need whatsoever for module.h

The advantage in removing such instances is that module.h itself
sources about 15 other headers; adding significantly to what we feed
cpp, and it can obscure what headers we are effectively using.

Since module.h was the source for init.h (for __init) and for
export.h (for EXPORT_SYMBOL) we consider each instance for the
presence of either and replace as needed. In this case, we did
not need to add either to any files.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14036/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

KVM: MIPS: Drop dubious EntryHi optimisation

There exists a slightly dubious optimisation in the implementation of
the MIPS KVM EntryHi emulation which skips TLB invalidation if the
EntryHi points to an address in the guest KSeg0 region, intended to
catch guest TLB invalidations where the ASID is almost immediately
restored to the previous value.

Now that we perform lazy host ASID regeneration for guest user mode when
the guest ASID changes we should be able to drop the optimisation
without a significant impact (only the extra TLB refills for the small
amount of code while the TLB is being invalidated).

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS: Invalidate TLB by regenerating ASIDs

Invalidate host TLB mappings when the guest ASID is changed by
regenerating ASIDs, rather than flushing the entire host TLB except
entries in the guest KSeg0 range.

For the guest kernel mode ASID we regenerate on the spot when the guest
ASID is changed, as that will always take place while the guest is in
kernel mode.

However when the guest invalidates TLB entries the ASID will often by
changed temporarily as part of writing EntryHi without the guest
returning to user mode in between. We therefore regenerate the user mode
ASID lazily before entering the guest in user mode, if and only if the
guest ASID has actually changed since the last guest user mode entry.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

KVM: MIPS: Drop other CPU ASIDs on guest MMU changes

When a guest TLB entry is replaced by TLBWI or TLBWR, we only invalidate
TLB entries on the local CPU. This doesn't work correctly on an SMP host
when the guest is migrated to a different physical CPU, as it could pick
up stale TLB mappings from the last time the vCPU ran on that physical
CPU.

Therefore invalidate both user and kernel host ASIDs on other CPUs,
which will cause new ASIDs to be generated when it next runs on those
CPUs.

We're careful only to do this if the TLB entry was already valid, and
only for the kernel ASID where the virtual address it mapped is outside
of the guest user address range.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: <stable@vger.kernel.org> # 3.10.x-

MIPS: KVM: Propagate kseg0/mapped tlb fault errors

Propagate errors from kvm_mips_handle_kseg0_tlb_fault() and
kvm_mips_handle_mapped_seg_tlb_fault(), usually triggering an internal
error since they normally indicate the guest accessed bad physical
memory or the commpage in an unexpected way.

Fixes: 858dd5d45733 ("KVM/MIPS32: MMU/TLB operations for the Guest.")
Fixes: e685c689f3a8 ("KVM/MIPS32: Privileged instruction/target branch emulation.")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: <stable@vger.kernel.org> # 3.10.x-
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

MIPS: KVM: Sign extend MFC0/RDHWR results

When emulating MFC0 instructions to load 32-bit values from guest COP0
registers and the RDHWR instruction to read the CC (Count) register,
sign extend the result to comply with the MIPS64 architecture. The
result must be in canonical 32-bit form or the guest may malfunction.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Decode RDHWR more strictly

When KVM emulates the RDHWR instruction, decode the instruction more
strictly. The rs field (bits 25:21) should be zero, as should bits 10:9.
Bits 8:6 is the register select field in MIPSr6, so we aren't strict
about those bits (no other operations should use that encoding space).

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim KrÄmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Recognise r6 CACHE encoding

Recognise the new MIPSr6 CACHE instruction encoding rather than the
pre-r6 one when an r6 kernel is being built. A SPECIAL3 opcode is used
and the immediate field is reduced to 9 bits wide since MIPSr6.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim KrÄmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Support r6 compact branch emulation

Add support in KVM for emulation of instructions in the forbidden slot
of MIPSr6 compact branches. If we hit an exception on the forbidden
slot, then the branch must not have been taken, which makes calculation
of the resume PC trivial.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim KrÄmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Add KScratch registers

Allow up to 6 KVM guest KScratch registers to be enabled and accessed
via the KVM guest register API and from the guest itself (the fallback
reading and writing of commpage registers is sufficient for KScratch
registers to work as expected).

User mode can expose the registers by setting the appropriate bits of
the guest Config4.KScrExist field. KScratch registers that aren't usable
won't be writeable via the KVM Ioctl API.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Emulate RDHWR CPUNum register

Actually provide the VCPU number when emulating the RDHWR CPUNum
register, so that it will match the CPUNum field of CP0_EBase register,
rather than always returning 0.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Allow ULRI to restrict UserLocal register

The ULRI bit in Config3 specifies whether the UserLocal register is
implemented, but it is assumed to always be set. Now that the Config
registers can be modified by userland, allow Config3.ULRI to be cleared
and check ULRI before allowing the corresponding bit to be set in
HWREna.

In fact any HWREna bits corresponding to unimplemented RDHWR registers
should read as zero and be ignored on write, so we actually prevent
other unimplemented bits being set too.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: Clean up RDHWR handling

No preprocessor definitions are used in the handling of the registers
accessible with the RDHWR instruction, nor the corresponding bits in the
CP0 HWREna register.

Add definitions for both the register numbers (MIPS_HWR_*) and HWREna
bits (MIPS_HWRENA_*) in asm/mipsregs.h and make use of them in the
initialisation of HWREna and emulation of the RDHWR instruction.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: David Daney <david.daney@cavium.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Convert emulation to use asm/inst.h

Convert various MIPS KVM guest instruction emulation functions to decode
instructions (and encode translations) using the union mips_instruction
and related enumerations in asm/inst.h rather than #defines and
hardcoded values.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Print unknown load/store encodings

When trying to emulate an unrecognised load or store instruction, print
the encoding to aid debug.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Trace guest register access emulation

Trace emulation of guest access to various registers via
MFC0/MTC0/DMFC0/DMTC0 instructions (coprocessor 0) and the RDHWR
instruction (hardware registers exposed to userland), replacing some
existing kvm_debug calls. Trace events are much more practical for this
kind of debug output.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Add kvm_asid_change trace event

Add a trace event for guest ASID changes, replacing the existing
kvm_debug call.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Clean up kvm_exit trace event

Clean up the MIPS kvm_exit trace event so that the exit reasons are
specified in a trace friendly way (via __print_symbolic), and so that
the exit reasons that derive straight from Cause.ExcCode values map
directly, allowing a single trace_kvm_exit() call to replace a bunch of
individual ones.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Generalise fpu_inuse for other state

Rename fpu_inuse and the related definitions to aux_inuse so it can be
used for lazy context management of other auxiliary processor state too,
such as VZ guest timer, watchpoints and performance counters.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Arrayify struct kvm_mips_tlb::tlb_lo*

The values of the EntryLo0 and EntryLo1 registers for a TLB entry are
stored in separate members of struct kvm_mips_tlb called tlb_lo0 and
tlb_lo1 respectively. To allow future code which needs to manipulate
arbitrary EntryLo data in the TLB entry to be simpler and less
conditional, replace these members with an array of two elements.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Drop unused hpa0/hpa1 args from function

The function kvm_mips_handle_mapped_seg_tlb_fault() has two completely
unused pointer arguments, hpa0 and hpa1, for which all users always pass
NULL.

Drop these two arguments and update the callers.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Make various Cause variables 32-bit

The CP0 Cause register is passed around in KVM quite a bit, often as an
unsigned long, even though it is always 32-bits long.

Resize it to u32 throughout MIPS KVM.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Convert code to kernel sized types

Convert the MIPS KVM C code to use standard kernel sized types (e.g.
u32) instead of inttypes.h style ones (e.g. uint32_t) or other types as
appropriate.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Convert headers to kernel sized types

Convert the MIPS kvm_host.h structs, function declaration prototypes and
associated definition prototypes to use standard kernel sized types
(e.g. u32) instead of inttypes.h style ones (e.g. uint32_t).

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Drop unused kvm_mips_sync_icache()

The function kvm_mips_sync_icache() is unused, so lets remove it.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Drop unused host_cp0_entryhi

The host EntryHi in the KVM VCPU context is virtually unused. It gets
stored on exceptions, but only ever used in a kvm_debug() when a TLB
miss occurs.

Drop it entirely, removing that information from the kvm_debug output.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Fix CACHE triggered exception emulation

When emulating TLB miss / invalid exceptions during CACHE instruction
emulation, be sure to set up the correct PC and host_cp0_badvaddr state
for the kvm_mips_emlulate_tlb*_ld() function to pick up for guest EPC
and BadVAddr.

PC needs to be rewound otherwise the guest EPC will end up pointing at
the next instruction after the faulting CACHE instruction.

host_cp0_badvaddr must be set because guest CACHE instructions trap with
a Coprocessor Unusable exception, which doesn't update the host BadVAddr
as a TLB exception would.

This doesn't tend to get hit when dynamic translation of emulated
instructions is enabled, since only the first execution of each CACHE
instruction actually goes through this code path, with subsequent
executions hitting the SYNCI instruction that it gets replaced with.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Don't unwind PC when emulating CACHE

When a CACHE instruction is emulated by kvm_mips_emulate_cache(), the PC
is first updated to point to the next instruction, and afterwards it
falls through the "dont_update_pc" label, which rewinds the PC back to
its original address.

This works when dynamic translation of emulated instructions is enabled,
since the CACHE instruction is replaced with a SYNCI which works without
trapping, however when dynamic translation is disabled the guest hangs
on CACHE instructions as they always trap and are never stepped over.

Roughly swap the meanings of the "done" and "dont_update_pc" to match
kvm_mips_emulate_CP0(), so that "done" will roll back the PC on failure,
and "dont_update_pc" won't change PC at all (for the sake of exceptions
that have already modified the PC).

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Abstract guest ASID mask

In preparation for supporting varied widths of ASID mask in the kernel
in general, switch KVM's guest ASIDs to a new KVM_ENTRYHI_ASID
definition based on the 8-bit MIPS_ENTRYHI_ASID instead of ASID_MASK.

It could potentially be used to support extended guest ASIDs in the
future.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13207/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: KVM: Fix timer IRQ race when writing CP0_Compare

Writing CP0_Compare clears the timer interrupt pending bit
(CP0_Cause.TI), but this wasn't being done atomically. If a timer
interrupt raced with the write of the guest CP0_Compare, the timer
interrupt could end up being pending even though the new CP0_Compare is
nowhere near CP0_Count.

We were already updating the hrtimer expiry with
kvm_mips_update_hrtimer(), which used both kvm_mips_freeze_hrtimer() and
kvm_mips_resume_hrtimer(). Close the race window by expanding out
kvm_mips_update_hrtimer(), and clearing CP0_Cause.TI and setting
CP0_Compare between the freeze and resume. Since the pending timer
interrupt should not be cleared when CP0_Compare is written via the KVM
user API, an ack argument is added to distinguish the source of the
write.

Fixes: e30492bbe95a ("MIPS: KVM: Rewrite count/compare timer emulation")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: <stable@vger.kernel.org> # 3.16.x-
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Fix timer IRQ race when freezing timer

There's a particularly narrow and subtle race condition when the
software emulated guest timer is frozen which can allow a guest timer
interrupt to be missed.

This happens due to the hrtimer expiry being inexact, so very
occasionally the freeze time will be after the moment when the emulated
CP0_Count transitions to the same value as CP0_Compare (so an IRQ should
be generated), but before the moment when the hrtimer is due to expire
(so no IRQ is generated). The IRQ won't be generated when the timer is
resumed either, since the resume CP0_Count will already match CP0_Compare.

With VZ guests in particular this is far more likely to happen, since
the soft timer may be frozen frequently in order to restore the timer
state to the hardware guest timer. This happens after 5-10 hours of
guest soak testing, resulting in an overflow in guest kernel timekeeping
calculations, hanging the guest. A more focussed test case to
intentionally hit the race (with the help of a new hypcall to cause the
timer state to migrated between hardware & software) hits the condition
fairly reliably within around 30 seconds.

Instead of relying purely on the inexact hrtimer expiry to determine
whether an IRQ should be generated, read the guest CP0_Compare and
directly check whether the freeze time is before or after it. Only if
CP0_Count is on or after CP0_Compare do we check the hrtimer expiry to
determine whether the last IRQ has already been generated (which will
have pushed back the expiry by one timer period).

Fixes: e30492bbe95a ("MIPS: KVM: Rewrite count/compare timer emulation")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: <stable@vger.kernel.org> # 3.16.x-
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: Move KVM specific opcodes into asm/inst.h

The header arch/mips/kvm/opcode.h defines a few extra opcodes which
aren't in arch/mips/include/uapi/asm/inst.h. There's nothing KVM
specific about them, so lets move them into inst.h where they belong and
delete the header.

Note that mfmcz_op is renamed to mfmc0_op to match the instruction set
manual, and wait_op was already added to inst.h in commit b0a3eae2b943
("MIPS: inst.h: define COP0 wait op"), merged in v3.16-rc1.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11895/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: KVM: Use cacheops.h definitions

Drop the custom cache operation code definitions used by KVM for
emulating guest CACHE instructions, and switch to use the existing
definitions in <asm/cacheops.h>.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11893/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Move Cause.ExcCode trap codes to mipsregs.h

Move the Cause.ExcCode trap code definitions from kvm_host.h to
mipsregs.h, since they describe architectural bits rather than KVM
specific constants, and change the prefix from T_ to EXCCODE_.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11891/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: KVM: Trivial whitespace and style fixes

A bunch of misc whitespace and style fixes within arch/mips/kvm/.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11883/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

kvm: rename pfn_t to kvm_pfn_t

To date, we have implemented two I/O usage models for persistent memory,
PMEM (a persistent "ram disk") and DAX (mmap persistent memory into
userspace). This series adds a third, DAX-GUP, that allows DAX mappings
to be the target of direct-i/o. It allows userspace to coordinate
DMA/RDMA from/to persistent memory.

The implementation leverages the ZONE_DEVICE mm-zone that went into
4.3-rc1 (also discussed at kernel summit) to flag pages that are owned
and dynamically mapped by a device driver. The pmem driver, after
mapping a persistent memory range into the system memmap via
devm_memremap_pages(), arranges for DAX to distinguish pfn-only versus
page-backed pmem-pfns via flags in the new pfn_t type.

The DAX code, upon seeing a PFN_DEV+PFN_MAP flagged pfn, flags the
resulting pte(s) inserted into the process page tables with a new
_PAGE_DEVMAP flag. Later, when get_user_pages() is walking ptes it keys
off _PAGE_DEVMAP to pin the device hosting the page range active.
Finally, get_page() and put_page() are modified to take references
against the device driver established page mapping.

Finally, this need for "struct page" for persistent memory requires
memory capacity to store the memmap array. Given the memmap array for a
large pool of persistent may exhaust available DRAM introduce a
mechanism to allocate the memmap from persistent memory. The new
"struct vmem_altmap *" parameter to devm_memremap_pages() enables
arch_add_memory() to use reserved pmem capacity rather than the page
allocator.

This patch (of 18):

The core has developed a need for a "pfn_t" type [1]. Move the existing
pfn_t in KVM to kvm_pfn_t [2].

[1]: https://lists.01.org/pipermail/linux-nvdimm/2015-September/002199.html
[2]: https://lists.01.org/pipermail/linux-nvdimm/2015-September/002218.html

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

MIPS: KVM: Fix CACHE immediate offset sign extension

The immediate field of the CACHE instruction is signed, so ensure that
it gets sign extended by casting it to an int16_t rather than just
masking the low 16 bits.

Fixes: e685c689f3a8 ("KVM/MIPS32: Privileged instruction/target branch emulation.")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: <stable@vger.kernel.org> # 3.10.x-
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Do not sign extend on unsigned MMIO load

Fix possible unintended sign extension in unsigned MMIO loads by casting
to uint16_t in the case of mmio_needed != 2.

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Tested-by: James Hogan <james.hogan@imgtec.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/9985/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: KVM: Fix unused variable build warning

As kvm_mips_complete_mmio_load() did not yet modify PC at this point
as James Hogans <james.hogan@imgtec.com> explained the curr_pc variable
and the comments along with it can be dropped.

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Link: http://lkml.org/lkml/2015/5/8/422
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/9993/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: KVM: Add MSA exception handling

Add guest exception handling for MIPS SIMD Architecture (MSA) floating
point exceptions and MSA disabled exceptions.

MSA floating point exceptions from the guest need passing to the guest
kernel, so for these a guest MSAFPE is emulated.

MSA disabled exceptions are normally handled by passing a reserved
instruction exception to the guest (because no guest MSA was supported),
but the hypervisor can now handle them if the guest has MSA by passing
an MSA disabled exception to the guest, or if the guest has MSA enabled
by transparently restoring the guest MSA context and enabling MSA and
the FPU.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

MIPS: KVM: Emulate MSA bits in COP0 interface

Emulate MSA related parts of COP0 interface so that the guest will be
able to enable/disable MSA (Config5.MSAEn) once the MSA capability has
been wired up.

As with the FPU (Status.CU1) setting Config5.MSAEn has no immediate
effect if the MSA state isn't live, as MSA state is restored lazily on
first use. Changes after the MSA state has been restored take immediate
effect, so that the guest can start getting MSA disabled exceptions
right away for guest MSA operations. The MSA state is saved lazily too,
as MSA may get re-enabled in the near future anyway.

A special case is also added for when Status.CU1 is set while FR=0 and
the MSA state is live. In this case we are at risk of getting reserved
instruction exceptions if we try and save the MSA state, so we lose the
MSA state sooner while MSA is still usable.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

MIPS: KVM: Add FP exception handling

Add guest exception handling for floating point exceptions and
coprocessor 1 unusable exceptions.

Floating point exceptions from the guest need passing to the guest
kernel, so for these a guest FPE is emulated.

Also, coprocessor 1 unusable exceptions are normally passed straight
through to the guest (because no guest FPU was supported), but the
hypervisor can now handle them if the guest has its FPU enabled by
restoring the guest FPU context and enabling the FPU.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

MIPS: KVM: Emulate FPU bits in COP0 interface

Emulate FPU related parts of COP0 interface so that the guest will be
able to enable/disable the following once the FPU capability has been
wired up:
- The FPU (Status.CU1)
- 64-bit FP register mode (Status.FR)
- Hybrid FP register mode (Config5.FRE)

Changing Status.CU1 has no immediate effect if the FPU state isn't live,
as the FPU state is restored lazily on first use. After that, changes
take place immediately in the host Status.CU1, so that the guest can
start getting coprocessor unusable exceptions right away for guest FPU
operations if it is disabled. The FPU state is saved lazily too, as the
FPU may get re-enabled in the near future anyway.

Any change to Status.FR causes the FPU state to be discarded and FPU
disabled, as the register state is architecturally UNPREDICTABLE after
such a change. This should also ensure that the FPU state is fully
initialised (with stale state, but that's fine) when it is next used in
the new FP mode.

Any change to the Config5.FRE bit is immediately updated in the host
state so that the guest can get the relevant exceptions right away for
single-precision FPU operations.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

MIPS: KVM: Add Config4/5 and writing of Config registers

Add Config4 and Config5 co-processor 0 registers, and add capability to
write the Config1, Config3, Config4, and Config5 registers using the KVM
API.

Only supported bits can be written, to minimise the chances of the guest
being given a configuration from e.g. QEMU that is inconsistent with
that being emulated, and as such the handling is in trap_emul.c as it
may need to be different for VZ. Currently the only modification
permitted is to make Config4 and Config5 exist via the M bits, but other
bits will be added for FPU and MSA support in future patches.

Care should be taken by userland not to change bits without fully
handling the possible extra state that may then exist and which the
guest may begin to use and depend on.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

MIPS: KVM: Handle TRAP exceptions from guest kernel

Trap instructions are used by Linux to implement BUG_ON(), however KVM
doesn't pass trap exceptions on to the guest if they occur in guest
kernel mode, instead triggering an internal error "Exception Code: 13,
not yet handled". The guest kernel then doesn't get a chance to print
the usual BUG message and stack trace.

Implement handling of the trap exception so that it gets passed to the
guest and the user is left with a more useful log message.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org

MIPS: KVM: Handle MSA Disabled exceptions from guest

Guest user mode can generate a guest MSA Disabled exception on an MSA
capable core by simply trying to execute an MSA instruction. Since this
exception is unknown to KVM it will be passed on to the guest kernel.
However guest Linux kernels prior to v3.15 do not set up an exception
handler for the MSA Disabled exception as they don't support any MSA
capable cores. This results in a guest OS panic.

Since an older processor ID may be being emulated, and MSA support is
not advertised to the guest, the correct behaviour is to generate a
Reserved Instruction exception in the guest kernel so it can send the
guest process an illegal instruction signal (SIGILL), as would happen
with a non-MSA-capable core.

Fix this as minimally as reasonably possible by preventing
kvm_mips_check_privilege() from relaying MSA Disabled exceptions from
guest user mode to the guest kernel, and handling the MSA Disabled
exception by emulating a Reserved Instruction exception in the guest,
via a new handle_msa_disabled() KVM callback.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: <stable@vger.kernel.org> # v3.15+

MIPS: KVM: Remove dead code of TLB index error in kvm_mips_emul_tlbwr()

It's impossible to fall into the error handling of the TLB index after
being masked by (KVM_MIPS_GUEST_TLB_SIZE - 1). Remove the dead code.

Reported-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: KVM: Rename files to remove the prefix "kvm_" and "kvm_mips_"

Since all the files are in arch/mips/kvm/, there's no need of the prefixes
"kvm_" and "kvm_mips_".

Reviewed-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>