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: PPC: Book3s: PR: Enable default TCE hypercalls

When KVM_CAP_PPC_ENABLE_HCALL was introduced, H_GET_TCE and H_PUT_TCE
were already implemented and enabled by default; however H_GET_TCE
was missed out on PR KVM (probably because the handler was in
the real mode code at the time).

This enables H_GET_TCE by default. While at this, this wraps
the checks in ifdef CONFIG_SPAPR_TCE_IOMMU just like HV KVM.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220506073737.3823347-1-aik@ozlabs.ru

KVM: PPC: Book3S PR: Disallow AIL != 0

KVM PR does not implement address translation modes on interrupt, so it
must not allow H_SET_MODE to succeed. The behaviour change caused by
this mode is architected and not advisory (interrupts *must* behave
differently).

QEMU does not deal with differences in AIL support in the host. The
solution to that is a spapr capability and corresponding KVM CAP, but
this patch does not break things more than before (the host behaviour
already differs, this change just disallows some modes that are not
implemented properly).

By happy coincidence, this allows PR Linux guests that are using the SCV
facility to boot and run, because Linux disables the use of SCV if AIL
can not be set to 3. This does not fix the underlying problem of missing
SCV support (an OS could implement real-mode SCV vectors and try to
enable the facility). The true fix for that is for KVM PR to emulate scv
interrupts from the facility unavailable interrupt.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Link: https://lore.kernel.org/r/20220222064727.2314380-3-npiggin@gmail.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>

KVM: stats: Separate generic stats from architecture specific ones

Generic KVM stats are those collected in architecture independent code
or those supported by all architectures; put all generic statistics in
a separate structure. This ensures that they are defined the same way
in the statistics API which is being added, removing duplication among
different architectures in the declaration of the descriptors.

No functional change intended.

Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Ricardo Koller <ricarkol@google.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Jing Zhang <jingzhangos@google.com>
Message-Id: <20210618222709.1858088-2-jingzhangos@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

KVM: PPC: Book3S PR: Enable in-kernel TCE handlers for PR KVM

The handlers support PR KVM from the day one; however the PR KVM's
enable/disable hcalls handler missed these ones.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

KVM: PPC: Book3S PR: Don't include SPAPR TCE code on non-pseries platforms

Commit e91aa8e6ecd5 ("KVM: PPC: Enable IOMMU_API for KVM_BOOK3S_64
permanently", 2017-03-22) enabled the SPAPR TCE code for all 64-bit
Book 3S kernel configurations in order to simplify the code and
reduce #ifdefs. However, 64-bit Book 3S PPC platforms other than
pseries and powernv don't implement the necessary IOMMU callbacks,
leading to build failures like the following (for a pasemi config):

scripts/kconfig/conf --silentoldconfig Kconfig
warning: (KVM_BOOK3S_64) selects SPAPR_TCE_IOMMU which has unmet direct dependencies (IOMMU_SUPPORT && (PPC_POWERNV || PPC_PSERIES))

...

CC [M] arch/powerpc/kvm/book3s_64_vio.o
/home/paulus/kernel/kvm/arch/powerpc/kvm/book3s_64_vio.c: In function ‘kvmppc_clear_tce’:
/home/paulus/kernel/kvm/arch/powerpc/kvm/book3s_64_vio.c:363:2: error: implicit declaration of function ‘iommu_tce_xchg’ [-Werror=implicit-function-declaration]
iommu_tce_xchg(tbl, entry, &hpa, &dir);
^

To fix this, we make the inclusion of the SPAPR TCE support, and the
code that uses it in book3s_vio.c and book3s_vio_hv.c, depend on
the inclusion of support for the pseries and/or powernv platforms.
This means that when running a 'pseries' guest on those platforms,
the guest won't have in-kernel acceleration of the PAPR TCE hypercalls,
but at least now they compile.

Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

KVM: PPC: Book3S PR: Check copy_to/from_user return values

The PR KVM implementation of the PAPR HPT hypercalls (H_ENTER etc.)
access an image of the HPT in userspace memory using copy_from_user
and copy_to_user. Recently, the declarations of those functions were
annotated to indicate that the return value must be checked. Since
this code doesn't currently check the return value, this causes
compile warnings like the ones shown below, and since on PPC the
default is to compile arch/powerpc with -Werror, this causes the
build to fail.

To fix this, we check the return values, and if non-zero, fail the
hypercall being processed with a H_FUNCTION error return value.
There is really no good error return value to use since PAPR didn't
envisage the possibility that the hypervisor may not be able to access
the guest's HPT, and H_FUNCTION (function not supported) seems as
good as any.

The typical compile warnings look like this:

CC arch/powerpc/kvm/book3s_pr_papr.o
/home/paulus/kernel/kvm/arch/powerpc/kvm/book3s_pr_papr.c: In function ‘kvmppc_h_pr_enter’:
/home/paulus/kernel/kvm/arch/powerpc/kvm/book3s_pr_papr.c:53:2: error: ignoring return value of ‘copy_from_user’, declared with attribute warn_unused_result [-Werror=unused-result]
copy_from_user(pteg, (void __user *)pteg_addr, sizeof(pteg));
^
/home/paulus/kernel/kvm/arch/powerpc/kvm/book3s_pr_papr.c:74:2: error: ignoring return value of ‘copy_to_user’, declared with attribute warn_unused_result [-Werror=unused-result]
copy_to_user((void __user *)pteg_addr, hpte, HPTE_SIZE);
^

... etc.

Signed-off-by: Paul Mackerras <paulus@ozlabs.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>

Replace <asm/uaccess.h> with <linux/uaccess.h> globally

This was entirely automated, using the script by Al:

PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

KVM: PPC: Add support for multiple-TCE hcalls

This adds real and virtual mode handlers for the H_PUT_TCE_INDIRECT and
H_STUFF_TCE hypercalls for user space emulated devices such as IBMVIO
devices or emulated PCI. These calls allow adding multiple entries
(up to 512) into the TCE table in one call which saves time on
transition between kernel and user space.

The current implementation of kvmppc_h_stuff_tce() allows it to be
executed in both real and virtual modes so there is one helper.
The kvmppc_rm_h_put_tce_indirect() needs to translate the guest address
to the host address and since the translation is different, there are
2 helpers - one for each mode.

This implements the KVM_CAP_PPC_MULTITCE capability. When present,
the kernel will try handling H_PUT_TCE_INDIRECT and H_STUFF_TCE if these
are enabled by the userspace via KVM_CAP_PPC_ENABLE_HCALL.
If they can not be handled by the kernel, they are passed on to
the user space. The user space still has to have an implementation
for these.

Both HV and PR-syle KVM are supported.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

kvmppc: Implement H_LOGICAL_CI_{LOAD,STORE} in KVM

On POWER, storage caching is usually configured via the MMU - attributes
such as cache-inhibited are stored in the TLB and the hashed page table.

This makes correctly performing cache inhibited IO accesses awkward when
the MMU is turned off (real mode). Some CPU models provide special
registers to control the cache attributes of real mode load and stores but
this is not at all consistent. This is a problem in particular for SLOF,
the firmware used on KVM guests, which runs entirely in real mode, but
which needs to do IO to load the kernel.

To simplify this qemu implements two special hypercalls, H_LOGICAL_CI_LOAD
and H_LOGICAL_CI_STORE which simulate a cache-inhibited load or store to
a logical address (aka guest physical address). SLOF uses these for IO.

However, because these are implemented within qemu, not the host kernel,
these bypass any IO devices emulated within KVM itself. The simplest way
to see this problem is to attempt to boot a KVM guest from a virtio-blk
device with iothread / dataplane enabled. The iothread code relies on an
in kernel implementation of the virtio queue notification, which is not
triggered by the IO hcalls, and so the guest will stall in SLOF unable to
load the guest OS.

This patch addresses this by providing in-kernel implementations of the
2 hypercalls, which correctly scan the KVM IO bus. Any access to an
address not handled by the KVM IO bus will cause a VM exit, hitting the
qemu implementation as before.

Note that a userspace change is also required, in order to enable these
new hcall implementations with KVM_CAP_PPC_ENABLE_HCALL.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[agraf: fix compilation]
Signed-off-by: Alexander Graf <agraf@suse.de>

KVM: PPC: Book3S PR: Take SRCU read lock around RTAS kvm_read_guest() call

This does for PR KVM what c9438092cae4 ("KVM: PPC: Book3S HV: Take SRCU
read lock around kvm_read_guest() call") did for HV KVM, that is,
eliminate a "suspicious rcu_dereference_check() usage!" warning by
taking the SRCU lock around the call to kvmppc_rtas_hcall().

It also fixes a return of RESUME_HOST to return EMULATE_FAIL instead,
since kvmppc_h_pr() is supposed to return EMULATE_* values.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: stable@vger.kernel.org
Signed-off-by: Alexander Graf <agraf@suse.de>

KVM: PPC: Book3S: Allow only implemented hcalls to be enabled or disabled

This adds code to check that when the KVM_CAP_PPC_ENABLE_HCALL
capability is used to enable or disable in-kernel handling of an
hcall, that the hcall is actually implemented by the kernel.
If not an EINVAL error is returned.

This also checks the default-enabled list of hcalls and prints a
warning if any hcall there is not actually implemented.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

KVM: PPC: Book3S: Controls for in-kernel sPAPR hypercall handling

This provides a way for userspace controls which sPAPR hcalls get
handled in the kernel. Each hcall can be individually enabled or
disabled for in-kernel handling, except for H_RTAS. The exception
for H_RTAS is because userspace can already control whether
individual RTAS functions are handled in-kernel or not via the
KVM_PPC_RTAS_DEFINE_TOKEN ioctl, and because the numeric value for
H_RTAS is out of the normal sequence of hcall numbers.

Hcalls are enabled or disabled using the KVM_ENABLE_CAP ioctl for the
KVM_CAP_PPC_ENABLE_HCALL capability on the file descriptor for the VM.
The args field of the struct kvm_enable_cap specifies the hcall number
in args[0] and the enable/disable flag in args[1]; 0 means disable
in-kernel handling (so that the hcall will always cause an exit to
userspace) and 1 means enable. Enabling or disabling in-kernel
handling of an hcall is effective across the whole VM.

The ability for KVM_ENABLE_CAP to be used on a VM file descriptor
on PowerPC is new, added by this commit. The KVM_CAP_ENABLE_CAP_VM
capability advertises that this ability exists.

When a VM is created, an initial set of hcalls are enabled for
in-kernel handling. The set that is enabled is the set that have
an in-kernel implementation at this point. Any new hcall
implementations from this point onwards should not be added to the
default set without a good reason.

No distinction is made between real-mode and virtual-mode hcall
implementations; the one setting controls them both.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

KVM: PPC: Book3S PR: Fix sparse endian checks

While sending sparse with endian checks over the code base, it triggered at
some places that were missing casts or had wrong types. Fix them up.

Signed-off-by: Alexander Graf <agraf@suse.de>

KVM: PPC: Make shared struct aka magic page guest endian

The shared (magic) page is a data structure that contains often used
supervisor privileged SPRs accessible via memory to the user to reduce
the number of exits we have to take to read/write them.

When we actually share this structure with the guest we have to maintain
it in guest endianness, because some of the patch tricks only work with
native endian load/store operations.

Since we only share the structure with either host or guest in little
endian on book3s_64 pr mode, we don't have to worry about booke or book3s hv.

For booke, the shared struct stays big endian. For book3s_64 hv we maintain
the struct in host native endian, since it never gets shared with the guest.

For book3s_64 pr we introduce a variable that tells us which endianness the
shared struct is in and route every access to it through helper inline
functions that evaluate this variable.

Signed-off-by: Alexander Graf <agraf@suse.de>

KVM: PPC: Book3S PR: PAPR: Access HTAB in big endian

The HTAB on PPC is always in big endian. When we access it via hypercalls
on behalf of the guest and we're running on a little endian host, we need
to make sure we swap the bits accordingly.

Signed-off-by: Alexander Graf <agraf@suse.de>

KVM: PPC: Book3S PR: Make HPT accesses and updates SMP-safe

This adds a per-VM mutex to provide mutual exclusion between vcpus
for accesses to and updates of the guest hashed page table (HPT).
This also makes the code use single-byte writes to the HPT entry
when updating of the reference (R) and change (C) bits. The reason
for doing this, rather than writing back the whole HPTE, is that on
non-PAPR virtual machines, the guest OS might be writing to the HPTE
concurrently, and writing back the whole HPTE might conflict with
that. Also, real hardware does single-byte writes to update R and C.

The new mutex is taken in kvmppc_mmu_book3s_64_xlate() when reading
the HPT and updating R and/or C, and in the PAPR HPT update hcalls
(H_ENTER, H_REMOVE, etc.). Having the mutex means that we don't need
to use a hypervisor lock bit in the HPT update hcalls, and we don't
need to be careful about the order in which the bytes of the HPTE are
updated by those hcalls.

The other change here is to make emulated TLB invalidations (tlbie)
effective across all vcpus. To do this we call kvmppc_mmu_pte_vflush
for all vcpus in kvmppc_ppc_book3s_64_tlbie().

For 32-bit, this makes the setting of the accessed and dirty bits use
single-byte writes, and makes tlbie invalidate shadow HPTEs for all
vcpus.

With this, PR KVM can successfully run SMP guests.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

KVM: PPC: Book3S PR: Correct errors in H_ENTER implementation

The implementation of H_ENTER in PR KVM has some errors:

* With H_EXACT not set, if the HPTEG is full, we return H_PTEG_FULL
as the return value of kvmppc_h_pr_enter, but the caller is expecting
one of the EMULATE_* values. The H_PTEG_FULL needs to go in the
guest's R3 instead.

* With H_EXACT set, if the selected HPTE is already valid, the H_ENTER
call should return a H_PTEG_FULL error.

This fixes these errors and also makes it write only the selected HPTE,
not the whole group, since only the selected HPTE has been modified.
This also micro-optimizes the calculations involving pte_index and i.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

powerpc/kvm/book3s: Add support for H_IPOLL and H_XIRR_X in XICS emulation

This adds the remaining two hypercalls defined by PAPR for manipulating
the XICS interrupt controller, H_IPOLL and H_XIRR_X. H_IPOLL returns
information about the priority and pending interrupts for a virtual
cpu, without changing any state. H_XIRR_X is like H_XIRR in that it
reads and acknowledges the highest-priority pending interrupt, but it
also returns the timestamp (timebase register value) from when the
interrupt was first received by the hypervisor. Currently we just
return the current time, since we don't do any software queueing of
virtual interrupts inside the XICS emulation code.

These hcalls are not currently used by Linux guests, but may be in
future.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

KVM: PPC: Book3S: Add kernel emulation for the XICS interrupt controller

This adds in-kernel emulation of the XICS (eXternal Interrupt
Controller Specification) interrupt controller specified by PAPR, for
both HV and PR KVM guests.

The XICS emulation supports up to 1048560 interrupt sources.
Interrupt source numbers below 16 are reserved; 0 is used to mean no
interrupt and 2 is used for IPIs. Internally these are represented in
blocks of 1024, called ICS (interrupt controller source) entities, but
that is not visible to userspace.

Each vcpu gets one ICP (interrupt controller presentation) entity,
used to store the per-vcpu state such as vcpu priority, pending
interrupt state, IPI request, etc.

This does not include any API or any way to connect vcpus to their
ICP state; that will be added in later patches.

This is based on an initial implementation by Michael Ellerman
<michael@ellerman.id.au> reworked by Benjamin Herrenschmidt and
Paul Mackerras.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
[agraf: fix typo, add dependency on !KVM_MPIC]
Signed-off-by: Alexander Graf <agraf@suse.de>

KVM: PPC: Book3S: Add infrastructure to implement kernel-side RTAS calls

For pseries machine emulation, in order to move the interrupt
controller code to the kernel, we need to intercept some RTAS
calls in the kernel itself. This adds an infrastructure to allow
in-kernel handlers to be registered for RTAS services by name.
A new ioctl, KVM_PPC_RTAS_DEFINE_TOKEN, then allows userspace to
associate token values with those service names. Then, when the
guest requests an RTAS service with one of those token values, it
will be handled by the relevant in-kernel handler rather than being
passed up to userspace as at present.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
[agraf: fix warning]
Signed-off-by: Alexander Graf <agraf@suse.de>

powerpc/kvm: Fix "PR" KVM implementation of H_CEDE

H_CEDE should enable the vcpu's MSR:EE bit. It does on "HV" KVM (it's
burried in the assembly code though) and as far as I can tell, qemu
does it as well.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

kvm/book3s: Make kernel emulated H_PUT_TCE available for "PR" KVM

There is nothing in the code for emulating TCE tables in the kernel
that prevents it from working on "PR" KVM... other than ifdef's and
location of the code.

This and moves the bulk of the code there to a new file called
book3s_64_vio.c.

This speeds things up a bit on my G5.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[agraf: fix for hv kvm, 32bit, whitespace]
Signed-off-by: Alexander Graf <agraf@suse.de>

KVM: PPC: Ignore unhalt request from kvm_vcpu_block

When running kvm_vcpu_block and it realizes that the CPU is actually good
to run, we get a request bit set for KVM_REQ_UNHALT. Right now, there's
nothing we can do with that bit, so let's unset it right after the call
again so we don't get confused in our later checks for pending work.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

KVM: PPC: Book3s: PR: Add SPAPR H_BULK_REMOVE support

SPAPR support includes various in-kernel hypercalls, improving performance
by cutting out the exit to userspace. H_BULK_REMOVE is implemented in this
patch.

Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

KVM: PPC: Add PAPR hypercall code for PR mode

When running a PAPR guest, we need to handle a few hypercalls in kernel space,
most prominently the page table invalidation (to sync the shadows).

So this patch adds handling for a few PAPR hypercalls to PR mode KVM. I tried
to share the code with HV mode, but it ended up being a lot easier this way
around, as the two differ too much in those details.

Signed-off-by: Alexander Graf <agraf@suse.de>

---

v1 -> v2:

- whitespace fix