Trace the following Hyper SynIC events:
* set msr
* set sint irq
* ack sint
* sint irq eoi
Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
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: NPaolo Bonzini <pbonzini@redhat.com>

Consolidate updating the Hyper-V SynIC timers in a
single place: on guest entry in processing KVM_REQ_HV_STIMER
request.  This simplifies the overall logic, and makes sure
the most current state of msrs and guest clock is used for
arming the timers (to achieve that, KVM_REQ_HV_STIMER
has to be processed after KVM_REQ_CLOCK_UPDATE).
Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
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: NPaolo Bonzini <pbonzini@redhat.com>

QEMU zero-inits Hyper-V SynIC vectors. We should allow that,
and don't reject zero values if set by the host.
Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
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: NPaolo Bonzini <pbonzini@redhat.com>

Hypervisor Function Specification(HFS) doesn't require
to disable SynIC timer at timer config write if timer->count = 0.

So drop this check, this allow to load timers MSR's
during migration restore, because config are set before count
in QEMU side.

Also fix condition according to HFS doc(15.3.1):
"It is not permitted to set the SINTx field to zero for an
enabled timer. If attempted, the timer will be
marked disabled (that is, bit 0 cleared) immediately."
Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
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: NPaolo Bonzini <pbonzini@redhat.com>

Split stimer_expiration() into two parts - timer expiration message
sending and timer restart/cleanup based on timer state(config).

This also fixes a bug where a one-shot timer message whose delivery
failed once would get lost for good.
Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
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: NPaolo Bonzini <pbonzini@redhat.com>

This will be used in future to start Hyper-V SynIC timer
in several places by one logic in one function.

Changes v2:
* drop stimer->count == 0 check inside stimer_start()
* comment stimer_start() assumptions
Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
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: NPaolo Bonzini <pbonzini@redhat.com>

The function stimer_stop() is called in one place
so remove the function and replace it's call by function
content.
Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
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: NPaolo Bonzini <pbonzini@redhat.com>

Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
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: NPaolo Bonzini <pbonzini@redhat.com>

Since the numbers now overlap, it makes sense to enumerate
them in asm/kvm_host.h rather than linux/kvm_host.h.  Functions
that refer to architecture-specific requests are also moved
to arch/.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This makes sure the wall clock is updated only after an odd version value
is successfully written to guest memory.
Signed-off-by: NNicholas Krause <xerofoify@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The comment had the meaning of mmu.gva_to_gpa and nested_mmu.gva_to_gpa
swapped. Fix that, and also add some details describing how each translation
works.
Signed-off-by: NDavid Matlack <dmatlack@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Not just in order to clean up the code, but to make it faster by using
enhanced instructions: the initialization became 20-30% faster on our
testing machine.
Signed-off-by: NTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

It's possible that guest send us Hyper-V EOM at the middle
of Hyper-V SynIC timer running, so we start processing of Hyper-V
SynIC timers in vcpu context and stop the Hyper-V SynIC timer
unconditionally:

    host                                       guest
    ------------------------------------------------------------------------------
                                           start periodic stimer
    start periodic timer
    timer expires after 15ms
    send expiration message into guest
    restart periodic timer
    timer expires again after 15 ms
    msg slot is still not cleared so
    setup ->msg_pending
(1) restart periodic timer
                                           process timer msg and clear slot
                                           ->msg_pending was set:
                                               send EOM into host
    received EOM
      kvm_make_request(KVM_REQ_HV_STIMER)

    kvm_hv_process_stimers():
        ...
        stimer_stop()
        if (time_now >= stimer->exp_time)
                stimer_expiration(stimer);

Because the timer was rearmed at (1), time_now < stimer->exp_time
and stimer_expiration is not called.  The timer then never fires.

The patch fixes such situation by not stopping Hyper-V SynIC timer
at all, because it's safe to restart it without stop in vcpu context
and timer callback always returns HRTIMER_NORESTART.
Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
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: NPaolo Bonzini <pbonzini@redhat.com>

Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
---
	I am sending this as RFC because the error messages it produces are
	very ugly.  Because of inlining, the original line is lost.  The
	alternative is to change vmcs_read/write/checkXX into macros, but
	then you need to have a single huge BUILD_BUG_ON or BUILD_BUG_ON_MSG
	because multiple BUILD_BUG_ON* with the same __LINE__ are not
	supported well.

This was not printing the high parts of several 64-bit fields on
32-bit kernels.  Separate from the previous one to make the patches
easier to review.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

In theory this should have broken EPT on 32-bit kernels (due to
reading the high part of natural-width field GUEST_CR3).  Not sure
if no one noticed or the processor behaves differently from the
documentation.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

POSTED_INTR_NV is 16bit, should not use 64bit write function

[ 5311.676074] vmwrite error: reg 3 value 0 (err 12)
  [ 5311.680001] CPU: 49 PID: 4240 Comm: qemu-system-i38 Tainted: G I 4.1.13-WR8.0.0.0_standard #1
  [ 5311.689343] Hardware name: Intel Corporation S2600WT2/S2600WT2, BIOS SE5C610.86B.01.01.0008.021120151325 02/11/2015
  [ 5311.699550] 00000000 00000000 e69a7e1c c1950de1 00000000 e69a7e38 fafcff45 fafebd24
  [ 5311.706924] 00000003 00000000 0000000c b6a06dfa e69a7e40 fafcff79 e69a7eb0 fafd5f57
  [ 5311.714296] e69a7ec0 c1080600 00000000 00000001 c0e18018 000001be 00000000 00000b43
  [ 5311.721651] Call Trace:
  [ 5311.722942] [<c1950de1>] dump_stack+0x4b/0x75
  [ 5311.726467] [<fafcff45>] vmwrite_error+0x35/0x40 [kvm_intel]
  [ 5311.731444] [<fafcff79>] vmcs_writel+0x29/0x30 [kvm_intel]
  [ 5311.736228] [<fafd5f57>] vmx_create_vcpu+0x337/0xb90 [kvm_intel]
  [ 5311.741600] [<c1080600>] ? dequeue_task_fair+0x2e0/0xf60
  [ 5311.746197] [<faf3b9ca>] kvm_arch_vcpu_create+0x3a/0x70 [kvm]
  [ 5311.751278] [<faf29e9d>] kvm_vm_ioctl+0x14d/0x640 [kvm]
  [ 5311.755771] [<c1129d44>] ? free_pages_prepare+0x1a4/0x2d0
  [ 5311.760455] [<c13e2842>] ? debug_smp_processor_id+0x12/0x20
  [ 5311.765333] [<c10793be>] ? sched_move_task+0xbe/0x170
  [ 5311.769621] [<c11752b3>] ? kmem_cache_free+0x213/0x230
  [ 5311.774016] [<faf29d50>] ? kvm_set_memory_region+0x60/0x60 [kvm]
  [ 5311.779379] [<c1199fa2>] do_vfs_ioctl+0x2e2/0x500
  [ 5311.783285] [<c11752b3>] ? kmem_cache_free+0x213/0x230
  [ 5311.787677] [<c104dc73>] ? __mmdrop+0x63/0xd0
  [ 5311.791196] [<c104dc73>] ? __mmdrop+0x63/0xd0
  [ 5311.794712] [<c104dc73>] ? __mmdrop+0x63/0xd0
  [ 5311.798234] [<c11a2ed7>] ? __fget+0x57/0x90
  [ 5311.801559] [<c11a2f72>] ? __fget_light+0x22/0x50
  [ 5311.805464] [<c119a240>] SyS_ioctl+0x80/0x90
  [ 5311.808885] [<c1957d30>] sysenter_do_call+0x12/0x12
  [ 5312.059280] kvm: zapping shadow pages for mmio generation wraparound
  [ 5313.678415] kvm [4231]: vcpu0 disabled perfctr wrmsr: 0xc2 data 0xffff
  [ 5313.726518] kvm [4231]: vcpu0 unhandled rdmsr: 0x570
Signed-off-by: NLi RongQing <roy.qing.li@gmail.com>
Cc: Yang Zhang <yang.z.zhang@Intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Per Hyper-V specification (and as required by Hyper-V-aware guests),
SynIC provides 4 per-vCPU timers.  Each timer is programmed via a pair
of MSRs, and signals expiration by delivering a special format message
to the configured SynIC message slot and triggering the corresponding
synthetic interrupt.

Note: as implemented by this patch, all periodic timers are "lazy"
(i.e. if the vCPU wasn't scheduled for more than the timer period the
timer events are lost), regardless of the corresponding configuration
MSR.  If deemed necessary, the "catch up" mode (the timer period is
shortened until the timer catches up) will be implemented later.

Changes v2:
* Use remainder to calculate periodic timer expiration time
Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
CC: Gleb Natapov <gleb@kernel.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Haiyang Zhang <haiyangz@microsoft.com>
CC: Vitaly Kuznetsov <vkuznets@redhat.com>
CC: Roman Kagan <rkagan@virtuozzo.com>
CC: Denis V. Lunev <den@openvz.org>
CC: qemu-devel@nongnu.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The SynIC message protocol mandates that the message slot is claimed
by atomically setting message type to something other than HVMSG_NONE.
If another message is to be delivered while the slot is still busy,
message pending flag is asserted to indicate to the guest that the
hypervisor wants to be notified when the slot is released.

To make sure the protocol works regardless of where the message
sources are (kernel or userspace), clear the pending flag on SINT ACK
notification, and let the message sources compete for the slot again.
Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
CC: Gleb Natapov <gleb@kernel.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Haiyang Zhang <haiyangz@microsoft.com>
CC: Vitaly Kuznetsov <vkuznets@redhat.com>
CC: Roman Kagan <rkagan@virtuozzo.com>
CC: Denis V. Lunev <den@openvz.org>
CC: qemu-devel@nongnu.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This helper will be used also in Hyper-V SynIC timers implementation.
Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
CC: Gleb Natapov <gleb@kernel.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Haiyang Zhang <haiyangz@microsoft.com>
CC: Vitaly Kuznetsov <vkuznets@redhat.com>
CC: Roman Kagan <rkagan@virtuozzo.com>
CC: Denis V. Lunev <den@openvz.org>
CC: qemu-devel@nongnu.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
CC: Gleb Natapov <gleb@kernel.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Haiyang Zhang <haiyangz@microsoft.com>
CC: Vitaly Kuznetsov <vkuznets@redhat.com>
CC: Roman Kagan <rkagan@virtuozzo.com>
CC: Denis V. Lunev <den@openvz.org>
CC: qemu-devel@nongnu.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This rearrangement places functions declarations together
according to their functionality, so future additions
will be simplier.
Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
CC: Gleb Natapov <gleb@kernel.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Haiyang Zhang <haiyangz@microsoft.com>
CC: Vitaly Kuznetsov <vkuznets@redhat.com>
CC: Roman Kagan <rkagan@virtuozzo.com>
CC: Denis V. Lunev <den@openvz.org>
CC: qemu-devel@nongnu.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Signed-off-by: NTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

As kvm_mmu_get_page() was changed so that every parent pointer would not
get into the sp->parent_ptes chain before the entry pointed to by it was
set properly, we can use the for_each_rmap_spte macro instead of
pte_list_walk().
Signed-off-by: NTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Every time kvm_mmu_get_page() is called with a non-NULL parent_pte
argument, link_shadow_page() follows that to set the parent entry so
that the new mapping will point to the returned page table.

Moving parent_pte handling there allows to clean up the code because
parent_pte is passed to kvm_mmu_get_page() just for mark_unsync() and
mmu_page_add_parent_pte().

In addition, the patch avoids calling mark_unsync() for other parents in
the sp->parent_ptes chain than the newly added parent_pte, because they
have been there since before the current page fault handling started.
Signed-off-by: NTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Make kvm_mmu_alloc_page() do just what its name tells to do, and remove
the extra allocation error check and zero-initialization of parent_ptes:
shadow page headers allocated by kmem_cache_zalloc() are always in the
per-VCPU pools.
Signed-off-by: NTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

At some call sites of rmap_get_first() and rmap_get_next(), BUG_ON is
placed right after the call to detect unrelated sptes which must not be
found in the reverse-mapping list.

Move this check in rmap_get_first/next() so that all call sites, not
just the users of the for_each_rmap_spte() macro, will be checked the
same way.

One thing to keep in mind is that kvm_mmu_unlink_parents() also uses
rmap_get_first() to handle parent sptes.  The change will not break it
because parent sptes are present, at least until drop_parent_pte()
actually unlinks them, and not mmio-sptes.
Signed-off-by: NTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

is_rmap_spte(), originally named is_rmap_pte(), was introduced when the
simple reverse mapping was implemented by commit cd4a4e53
("[PATCH] KVM: MMU: Implement simple reverse mapping").  At that point,
its role was clear and only rmap_add() and rmap_remove() were using it
to select sptes that need to be reverse-mapped.

Independently of that, is_shadow_present_pte() was first introduced by
commit c7addb90 ("KVM: Allow not-present guest page faults to
bypass kvm") to do bypass_guest_pf optimization, which does not exist
any more.

These two seem to have changed their roles somewhat, and is_rmap_spte()
just calls is_shadow_present_pte() now.

Since using both of them without clear distinction just makes the code
confusing, remove is_rmap_spte().
Signed-off-by: NTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

mmu_set_spte()'s code is based on the assumption that the emulate
parameter has a valid pointer value if set_spte() returns true and
write_fault is not zero.  In other cases, emulate may be NULL, so a
NULL-check is needed.

Stop passing emulate pointer and make mmu_set_spte() return the emulate
value instead to clean up this complex interface.  Prefetch functions
can just throw away the return value.
Signed-off-by: NTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Both __mmu_unsync_walk() and mmu_pages_clear_parents() have three line
code which clears a bit in the unsync child bitmap; the former places it
inside a loop block and uses a few goto statements to jump to it.

A new helper function, clear_unsync_child_bit(), makes the code cleaner.
Signed-off-by: NTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Signed-off-by: NTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

New struct kvm_rmap_head makes the code type-safe to some extent.
Signed-off-by: NTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Commit 7a1638ce ("nEPT: Redefine EPT-specific link_shadow_page()",
2013-08-05) says:

    Since nEPT doesn't support A/D bit, we should not set those bit
    when building the shadow page table.

but this is not necessary.  Even though nEPT doesn't support A/D
bits, and hence the vmcs12 EPT pointer will never enable them,
we always use them for shadow page tables if available (see
construct_eptp in vmx.c).  So we can set the A/D bits freely
in the shadow page table.

This patch hence basically reverts commit 7a1638ce.

Cc: Yang Zhang <yang.z.zhang@Intel.com>
Cc: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Poor #AC was so unimportant until a few days ago that we were
not even tracing its name correctly.  But now it's all over
the place.

Cc: stable@vger.kernel.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

RDTSCP was never supported for AMD CPUs, which nobody noticed because
Linux does not use it.  But exactly the fact that Linux does not
use it makes the implementation very simple; we can freely trash
MSR_TSC_AUX while running the guest.

Cc: Joerg Roedel <joro@8bytes.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

If we do not do this, it is not properly saved and restored across
migration.  Windows notices due to its self-protection mechanisms,
and is very upset about it (blue screen of death).

Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

A new vcpu exit is introduced to notify the userspace of the
changes in Hyper-V SynIC configuration triggered by guest writing to the
corresponding MSRs.

Changes v4:
* exit into userspace only if guest writes into SynIC MSR's

Changes v3:
* added KVM_EXIT_HYPERV types and structs notes into docs
Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
Signed-off-by: NDenis 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: NPaolo Bonzini <pbonzini@redhat.com>

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: NAndrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
Signed-off-by: NDenis 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: NPaolo Bonzini <pbonzini@redhat.com>

The decision on whether to use hardware APIC virtualization used to be
taken globally, based on the availability of the feature in the CPU
and the value of a module parameter.

However, under certain circumstances we want to control it on per-vcpu
basis.  In particular, when the userspace activates HyperV synthetic
interrupt controller (SynIC), APICv has to be disabled as it's
incompatible with SynIC auto-EOI behavior.

To achieve that, introduce 'apicv_active' flag on struct
kvm_vcpu_arch, and kvm_vcpu_deactivate_apicv() function to turn APICv
off.  The flag is initialized based on the module parameter and CPU
capability, and consulted whenever an APICv-specific action is
performed.
Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
Signed-off-by: NDenis 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: NPaolo Bonzini <pbonzini@redhat.com>

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: NAndrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
Signed-off-by: NDenis 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: NPaolo Bonzini <pbonzini@redhat.com>