KVM: x86: Make Hyper-V emulation optional

Hyper-V emulation in KVM is a fairly big chunk and in some cases it may be
desirable to not compile it in to reduce module sizes as well as the attack
surface. Introduce CONFIG_KVM_HYPERV option to make it possible.

Note, there's room for further nVMX/nSVM code optimizations when
!CONFIG_KVM_HYPERV, this will be done in follow-up patches.

Reorganize Makefile a bit so all CONFIG_HYPERV and CONFIG_KVM_HYPERV files
are grouped together.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Tested-by: Jeremi Piotrowski <jpiotrowski@linux.microsoft.com>
Link: https://lore.kernel.org/r/20231205103630.1391318-13-vkuznets@redhat.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

KVM: x86: Unify pr_fmt to use module name for all KVM modules

Define pr_fmt using KBUILD_MODNAME for all KVM x86 code so that printks
use consistent formatting across common x86, Intel, and AMD code. In
addition to providing consistent print formatting, using KBUILD_MODNAME,
e.g. kvm_amd and kvm_intel, allows referencing SVM and VMX (and SEV and
SGX and ...) as technologies without generating weird messages, and
without causing naming conflicts with other kernel code, e.g. "SEV: ",
"tdx: ", "sgx: " etc.. are all used by the kernel for non-KVM subsystems.

Opportunistically move away from printk() for prints that need to be
modified anyways, e.g. to drop a manual "kvm: " prefix.

Opportunistically convert a few SGX WARNs that are similarly modified to
WARN_ONCE; in the very unlikely event that the WARNs fire, odds are good
that they would fire repeatedly and spam the kernel log without providing
unique information in each print.

Note, defining pr_fmt yields undesirable results for code that uses KVM's
printk wrappers, e.g. vcpu_unimpl(). But, that's a pre-existing problem
as SVM/kvm_amd already defines a pr_fmt, and thankfully use of KVM's
wrappers is relatively limited in KVM x86 code.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Message-Id: <20221130230934.1014142-35-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: x86: ioapic: Fix level-triggered EOI and userspace I/OAPIC reconfigure race

When scanning userspace I/OAPIC entries, intercept EOI for level-triggered
IRQs if the current vCPU has a pending and/or in-service IRQ for the
vector in its local API, even if the vCPU doesn't match the new entry's
destination. This fixes a race between userspace I/OAPIC reconfiguration
and IRQ delivery that results in the vector's bit being left set in the
remote IRR due to the eventual EOI not being forwarded to the userspace
I/OAPIC.

Commit 0fc5a36dd6b3 ("KVM: x86: ioapic: Fix level-triggered EOI and IOAPIC
reconfigure race") fixed the in-kernel IOAPIC, but not the userspace
IOAPIC configuration, which has a similar race.

Fixes: 0fc5a36dd6b3 ("KVM: x86: ioapic: Fix level-triggered EOI and IOAPIC reconfigure race")

Signed-off-by: Adamos Ttofari <attofari@amazon.de>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221208094415.12723-1-attofari@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: x86/xen: Make kvm_xen_set_evtchn() reusable from other places

Clean it up to return -errno on error consistently, while still being
compatible with the return conventions for kvm_arch_set_irq_inatomic()
and the kvm_set_irq() callback.

We use -ENOTCONN to indicate when the port is masked. No existing users
care, except that it's negative.

Also allow it to optimise the vCPU lookup. Unless we abuse the lapic
map, there is no quick lookup from APIC ID to a vCPU; the logic in
kvm_get_vcpu_by_id() will just iterate over all vCPUs till it finds
the one it wants. So do that just once and stash the result in the
struct kvm_xen_evtchn for next time.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220303154127.202856-8-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: x86/xen: Add KVM_IRQ_ROUTING_XEN_EVTCHN and event channel delivery

This adds basic support for delivering 2 level event channels to a guest.

Initially, it only supports delivery via the IRQ routing table, triggered
by an eventfd. In order to do so, it has a kvm_xen_set_evtchn_fast()
function which will use the pre-mapped shared_info page if it already
exists and is still valid, while the slow path through the irqfd_inject
workqueue will remap the shared_info page if necessary.

It sets the bits in the shared_info page but not the vcpu_info; that is
deferred to __kvm_xen_has_interrupt() which raises the vector to the
appropriate vCPU.

Add a 'verbose' mode to xen_shinfo_test while adding test cases for this.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20211210163625.2886-5-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: Use 'unsigned long' as kvm_for_each_vcpu()'s index

Everywhere we use kvm_for_each_vpcu(), we use an int as the vcpu
index. Unfortunately, we're about to move rework the iterator,
which requires this to be upgrade to an unsigned long.

Let's bite the bullet and repaint all of it in one go.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Message-Id: <20211116160403.4074052-7-maz@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

x86: Fix various typos in comments

Fix ~144 single-word typos in arch/x86/ code comments.

Doing this in a single commit should reduce the churn.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-kernel@vger.kernel.org

x86/kvm: Use msi_msg shadow structs

Use the bitfields in the x86 shadow structs instead of decomposing the
32bit value with macros.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201024213535.443185-17-dwmw2@infradead.org

treewide: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

KVM: x86: don't notify userspace IOAPIC on edge-triggered interrupt EOI

Commit 13db77347db1 ("KVM: x86: don't notify userspace IOAPIC on edge
EOI") said, edge-triggered interrupts don't set a bit in TMR, which means
that IOAPIC isn't notified on EOI. And var level indicates level-triggered
interrupt.
But commit 3159d36ad799 ("KVM: x86: use generic function for MSI parsing")
replace var level with irq.level by mistake. Fix it by changing irq.level
to irq.trig_mode.

Cc: stable@vger.kernel.org
Fixes: 3159d36ad799 ("KVM: x86: use generic function for MSI parsing")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: LAPIC: micro-optimize fixed mode ipi delivery

This patch optimizes redundancy logic before fixed mode ipi is delivered
in the fast path, broadcast handling needs to go slow path, so the delivery
mode repair can be delayed to before slow path.

Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: X86: Convert the last users of "shorthand = 0" to use macros

Change the last users of "shorthand = 0" to use APIC_DEST_NOSHORT.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: X86: Fix callers of kvm_apic_match_dest() to use correct macros

Callers of kvm_apic_match_dest() should always pass in APIC_DEST_*
macros for either dest_mode and short_hand parameters. Fix up all the
callers of kvm_apic_match_dest() that are not following the rule.

Since at it, rename the parameter from short_hand to shorthand in
kvm_apic_match_dest(), as suggested by Vitaly.

Reported-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reported-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: X86: Use APIC_DEST_* macros properly in kvm_lapic_irq.dest_mode

We were using either APIC_DEST_PHYSICAL|APIC_DEST_LOGICAL or 0|1 to
fill in kvm_lapic_irq.dest_mode. It's fine only because in most cases
when we check against dest_mode it's against APIC_DEST_PHYSICAL (which
equals to 0). However, that's not consistent. We'll have problem
when we want to start checking against APIC_DEST_LOGICAL, which does
not equals to 1.

This patch firstly introduces kvm_lapic_irq_dest_mode() helper to take
any boolean of destination mode and return the APIC_DEST_* macro.
Then, it replaces the 0|1 settings of irq.dest_mode with the helper.

Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

kvm: x86: check kvm_apic_sw_enabled() is enough

On delivering irq to apic, we iterate on vcpu and do the check like
this:

kvm_apic_present(vcpu)
kvm_lapic_enabled(vpu)
kvm_apic_present(vcpu) && kvm_apic_sw_enabled(vcpu->arch.apic)

Since we have already checked kvm_apic_present(), it is reasonable to
replace kvm_lapic_enabled() with kvm_apic_sw_enabled().

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 320

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms and conditions of the gnu general public license
version 2 as published by the free software foundation this program
is distributed in the hope it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not write to the free
software foundation inc 59 temple place suite 330 boston ma 02111
1307 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 33 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190530000435.254582722@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

KVM: x86: don't hold kvm->lock in KVM_SET_GSI_ROUTING

We needed the lock to avoid racing with creation of the irqchip on x86. As
kvm_set_irq_routing() calls srcu_synchronize_expedited(), this lock
might be held for a longer time.

Let's introduce an arch specific callback to check if we can actually
add irq routes. For x86, all we have to do is check if we have an
irqchip in the kernel. We don't need kvm->lock at that point as the
irqchip is marked as inititalized only when actually fully created.

Reported-by: Steve Rutherford <srutherford@google.com>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Fixes: 1df6ddede10a ("KVM: x86: race between KVM_SET_GSI_ROUTING and KVM_CREATE_IRQCHIP")
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: x86: use irqchip_kernel() to check for pic+ioapic

Although the current check is not wrong, this check explicitly includes
the pic.

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

KVM: x86: drop goto label in kvm_set_routing_entry()

No need for the goto label + local variable "r".

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

KVM: x86: KVM_IRQCHIP_PIC_MASTER only has 8 pins

Currently, one could set pin 8-15, implicitly referring to
KVM_IRQCHIP_PIC_SLAVE.

Get rid of the two local variables max_pin and delta on the way.

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

KVM: x86: get rid of pic_irqchip()

It seemed like a nice idea to encapsulate access to kvm->arch.vpic. But
as the usage is already mixed, internal locks are taken outside of i8259.c
and grepping for "vpic" only is much easier, let's just get rid of
pic_irqchip().

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

KVM: x86: check against irqchip_mode in kvm_set_routing_entry()

Let's replace the checks for pic_in_kernel() and ioapic_in_kernel() by
checks against irqchip_mode.

Also make sure that creation of any route is only possible if we have
an lapic in kernel (irqchip_in_kernel()) or if we are currently
inititalizing the irqchip.

This is necessary to switch pic_in_kernel() and ioapic_in_kernel() to
irqchip_mode, too.

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

sched/headers: Prepare to use <linux/rcuupdate.h> instead of <linux/rculist.h> in <linux/sched.h>

We don't actually need the full rculist.h header in sched.h anymore,
we will be able to include the smaller rcupdate.h header instead.

But first update code that relied on the implicit header inclusion.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

KVM: x86: simplify conditions with split/kernel irqchip

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: x86: prevent setup of invalid routes

The check in kvm_set_pic_irq() and kvm_set_ioapic_irq() was just a
temporary measure until the code improved enough for us to do this.

This changes APIC in a case when KVM_SET_GSI_ROUTING is called to set up pic
and ioapic routes before KVM_CREATE_IRQCHIP. Those rules would get overwritten
by KVM_CREATE_IRQCHIP at best, so it is pointless to allow it. Userspaces
hopefully noticed that things don't work if they do that and don't do that.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: x86: refactor pic setup in kvm_set_routing_entry

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: x86: check for pic and ioapic presence before use

Split irqchip allows pic and ioapic routes to be used without them being
created, which results in NULL access. Check for NULL and avoid it.
(The setup is too racy for a nicer solutions.)

Found by syzkaller:

general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in:
CPU: 3 PID: 11923 Comm: kworker/3:2 Not tainted 4.9.0-rc5+ #27
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Workqueue: events irqfd_inject
task: ffff88006a06c7c0 task.stack: ffff880068638000
RIP: 0010:[...] [...] __lock_acquire+0xb35/0x3380 kernel/locking/lockdep.c:3221
RSP: 0000:ffff88006863ea20 EFLAGS: 00010006
RAX: dffffc0000000000 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000039 RSI: 0000000000000000 RDI: 1ffff1000d0c7d9e
RBP: ffff88006863ef58 R08: 0000000000000001 R09: 0000000000000000
R10: 00000000000001c8 R11: 0000000000000000 R12: ffff88006a06c7c0
R13: 0000000000000001 R14: ffffffff8baab1a0 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff88006d100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004abdd0 CR3: 000000003e2f2000 CR4: 00000000000026e0
Stack:
ffffffff894d0098 1ffff1000d0c7d56 ffff88006863ecd0 dffffc0000000000
ffff88006a06c7c0 0000000000000000 ffff88006863ecf8 0000000000000082
0000000000000000 ffffffff815dd7c1 ffffffff00000000 ffffffff00000000
Call Trace:
[...] lock_acquire+0x2a2/0x790 kernel/locking/lockdep.c:3746
[...] __raw_spin_lock include/linux/spinlock_api_smp.h:144
[...] _raw_spin_lock+0x38/0x50 kernel/locking/spinlock.c:151
[...] spin_lock include/linux/spinlock.h:302
[...] kvm_ioapic_set_irq+0x4c/0x100 arch/x86/kvm/ioapic.c:379
[...] kvm_set_ioapic_irq+0x8f/0xc0 arch/x86/kvm/irq_comm.c:52
[...] kvm_set_irq+0x239/0x640 arch/x86/kvm/../../../virt/kvm/irqchip.c:101
[...] irqfd_inject+0xb4/0x150 arch/x86/kvm/../../../virt/kvm/eventfd.c:60
[...] process_one_work+0xb40/0x1ba0 kernel/workqueue.c:2096
[...] worker_thread+0x214/0x18a0 kernel/workqueue.c:2230
[...] kthread+0x328/0x3e0 kernel/kthread.c:209
[...] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:433

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: stable@vger.kernel.org
Fixes: 49df6397edfc ("KVM: x86: Split the APIC from the rest of IRQCHIP.")
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

kvm: x86: merge kvm_arch_set_irq and kvm_arch_set_irq_inatomic

kvm_arch_set_irq is unused since commit b97e6de9c96. Merge
its functionality with kvm_arch_set_irq_inatomic.

Reported-by: Jiang Biao <jiang.biao2@zte.com.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

KVM: x86: add KVM_CAP_X2APIC_API

KVM_CAP_X2APIC_API is a capability for features related to x2APIC
enablement. KVM_X2APIC_API_32BIT_FORMAT feature can be enabled to
extend APIC ID in get/set ioctl and MSI addresses to 32 bits.
Both are needed to support x2APIC.

The feature has to be enableable and disabled by default, because
get/set ioctl shifted and truncated APIC ID to 8 bits by using a
non-standard protocol inspired by xAPIC and the change is not
backward-compatible.

Changes to MSI addresses follow the format used by interrupt remapping
unit. The upper address word, that used to be 0, contains upper 24 bits
of the LAPIC address in its upper 24 bits. Lower 8 bits are reserved as
0. Using the upper address word is not backward-compatible either as we
didn't check that userspace zeroed the word. Reserved bits are still
not explicitly checked, but non-zero data will affect LAPIC addresses,
which will cause a bug.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: pass struct kvm to kvm_set_routing_entry

Arch-specific code will use it.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: x86: use generic function for MSI parsing

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: add missing memory barrier in kvm_{make,check}_request

kvm_make_request and kvm_check_request imply a producer-consumer
relationship; add implicit memory barriers to them. There was indeed
already a place that was adding an explicit smp_mb() to order between
kvm_check_request and the processing of the request. That memory
barrier can be removed (as an added benefit, kvm_check_request can use
smp_mb__after_atomic which is free on x86).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

kvm: x86: Convert ioapic->rtc_status.dest_map to a struct

Currently this is a bitmap which tracks which CPUs we expect
an EOI from. Move this bitmap to a struct so that we can
track additional information there.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: x86: Use vector-hashing to deliver lowest-priority interrupts

Use vector-hashing to deliver lowest-priority interrupts, As an
example, modern Intel CPUs in server platform use this method to
handle lowest-priority interrupts.

Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

kvm/x86: Hyper-V synthetic interrupt controller

SynIC (synthetic interrupt controller) is a lapic extension,
which is controlled via MSRs and maintains for each vCPU
- 16 synthetic interrupt "lines" (SINT's); each can be configured to
trigger a specific interrupt vector optionally with auto-EOI
semantics
- a message page in the guest memory with 16 256-byte per-SINT message
slots
- an event flag page in the guest memory with 16 2048-bit per-SINT
event flag areas

The host triggers a SINT whenever it delivers a new message to the
corresponding slot or flips an event flag bit in the corresponding area.
The guest informs the host that it can try delivering a message by
explicitly asserting EOI in lapic or writing to End-Of-Message (EOM)
MSR.

The userspace (qemu) triggers interrupts and receives EOM notifications
via irqfd with resampler; for that, a GSI is allocated for each
configured SINT, and irq_routing api is extended to support GSI-SINT
mapping.

Changes v4:
* added activation of SynIC by vcpu KVM_ENABLE_CAP
* added per SynIC active flag
* added deactivation of APICv upon SynIC activation

Changes v3:
* added KVM_CAP_HYPERV_SYNIC and KVM_IRQ_ROUTING_HV_SINT notes into
docs

Changes v2:
* do not use posted interrupts for Hyper-V SynIC AutoEOI vectors
* add Hyper-V SynIC vectors into EOI exit bitmap
* Hyper-V SyniIC SINT msr write logic simplified

Signed-off-by: Andrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Gleb Natapov <gleb@kernel.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Roman Kagan <rkagan@virtuozzo.com>
CC: Denis V. Lunev <den@openvz.org>
CC: qemu-devel@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

kvm/x86: split ioapic-handled and EOI exit bitmaps

The function to determine if the vector is handled by ioapic used to
rely on the fact that only ioapic-handled vectors were set up to
cause vmexits when virtual apic was in use.

We're going to break this assumption when introducing Hyper-V
synthetic interrupts: they may need to cause vmexits too.

To achieve that, introduce a new bitmap dedicated specifically for
ioapic-handled vectors, and populate EOI exit bitmap from it for now.

Signed-off-by: Andrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Gleb Natapov <gleb@kernel.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Roman Kagan <rkagan@virtuozzo.com>
CC: Denis V. Lunev <den@openvz.org>
CC: qemu-devel@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

kvm/irqchip: kvm_arch_irq_routing_update renaming split

Actually kvm_arch_irq_routing_update() should be
kvm_arch_post_irq_routing_update() as it's called at the end
of irq routing update.

This renaming frees kvm_arch_irq_routing_update function name.
kvm_arch_irq_routing_update() weak function which will be used
to update mappings for arch-specific irq routing entries
(in particular, the upcoming Hyper-V synthetic interrupts).

Signed-off-by: Andrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Gleb Natapov <gleb@kernel.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Roman Kagan <rkagan@virtuozzo.com>
CC: Denis V. Lunev <den@openvz.org>
CC: qemu-devel@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: x86: move kvm_set_irq_inatomic to legacy device assignment

The function is not used outside device assignment, and
kvm_arch_set_irq_inatomic has a different prototype. Move it here and
make it static to avoid confusion.

Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: x86: merge kvm_arch_set_irq with kvm_set_msi_inatomic

We do not want to do too much work in atomic context, in particular
not walking all the VCPUs of the virtual machine. So we want
to distinguish the architecture-specific injection function for irqfd
from kvm_set_msi. Since it's still empty, reuse the newly added
kvm_arch_set_irq and rename it to kvm_arch_set_irq_inatomic.

Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: x86: don't notify userspace IOAPIC on edge EOI

On real hardware, edge-triggered interrupts don't set a bit in TMR,
which means that IOAPIC isn't notified on EOI. Do the same here.

Staying in guest/kernel mode after edge EOI is what we want for most
devices. If some bugs could be nicely worked around with edge EOI
notifications, we should invest in a better interface.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: make kvm_set_msi_irq() public

Make kvm_set_msi_irq() public, we can use this function outside.

Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: Define a new interface kvm_intr_is_single_vcpu()

This patch defines a new interface kvm_intr_is_single_vcpu(),
which can returns whether the interrupt is for single-CPU or not.

It is used by VT-d PI, since now we only support single-CPU
interrupts, For lowest-priority interrupts, if user configures
it via /proc/irq or uses irqbalance to make it single-CPU, we
can use PI to deliver the interrupts to it. Full functionality
of lowest-priority support will be added later.

Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: x86: Add EOI exit bitmap inference

In order to support a userspace IOAPIC interacting with an in kernel
APIC, the EOI exit bitmaps need to be configurable.

If the IOAPIC is in userspace (i.e. the irqchip has been split), the
EOI exit bitmaps will be set whenever the GSI Routes are configured.
In particular, for the low MSI routes are reservable for userspace
IOAPICs. For these MSI routes, the EOI Exit bit corresponding to the
destination vector of the route will be set for the destination VCPU.

The intention is for the userspace IOAPICs to use the reservable MSI
routes to inject interrupts into the guest.

This is a slight abuse of the notion of an MSI Route, given that MSIs
classically bypass the IOAPIC. It might be worthwhile to add an
additional route type to improve clarity.

Compile tested for Intel x86.

Signed-off-by: Steve Rutherford <srutherford@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: x86: Split the APIC from the rest of IRQCHIP.

First patch in a series which enables the relocation of the
PIC/IOAPIC to userspace.

Adds capability KVM_CAP_SPLIT_IRQCHIP;

KVM_CAP_SPLIT_IRQCHIP enables the construction of LAPICs without the
rest of the irqchip.

Compile tested for x86.

Signed-off-by: Steve Rutherford <srutherford@google.com>
Suggested-by: Andrew Honig <ahonig@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

kvm: x86: Deliver MSI IRQ to only lowest prio cpu if msi_redir_hint is true

An MSI interrupt should only be delivered to the lowest priority CPU
when it has RH=1, regardless of the delivery mode. Modified
kvm_is_dm_lowest_prio() to check for either irq->delivery_mode == APIC_DM_LOWPRI
or irq->msi_redir_hint.

Moved kvm_is_dm_lowest_prio() into lapic.h and renamed to
kvm_lowest_prio_delivery().

Changed a check in kvm_irq_delivery_to_apic_fast() from
irq->delivery_mode == APIC_DM_LOWPRI to kvm_is_dm_lowest_prio().

Signed-off-by: James Sullivan <sullivan.james.f@gmail.com>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

kvm: x86: Extended struct kvm_lapic_irq with msi_redir_hint for MSI delivery

Extended struct kvm_lapic_irq with bool msi_redir_hint, which will
be used to determine if the delivery of the MSI should target only
the lowest priority CPU in the logical group specified for delivery.
(In physical dest mode, the RH bit is not relevant). Initialized the value
of msi_redir_hint to true when RH=1 in kvm_set_msi_irq(), and initialized
to false in all other cases.

Added value of msi_redir_hint to a debug message dump of an IRQ in
apic_send_ipi().

Signed-off-by: James Sullivan <sullivan.james.f@gmail.com>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

kvm: remove CONFIG_X86 #ifdefs from files formerly shared with ia64

Signed-off-by: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

kvm: x86: move ioapic.c and irq_comm.c back to arch/x86/

ia64 does not need them anymore. Ack notifiers become x86-specific
too.

Suggested-by: Gleb Natapov <gleb@kernel.org>
Reviewed-by: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>