Hi!
This is a series of bugfixes to the AVIC dynamic inhibition, which was
made while trying to fix bugs as much as possible in this area and trying
to make the AVIC+SYNIC conditional enablement work.
* Patches 1-6 are code from Sean Christopherson which
implement an alternative approach of inhibiting AVIC without
disabling its memslot.
Those patches are new in this version of the patchset.
* Patches 7-8 in this series fix a race condition which can cause
a lost write from a guest to APIC when the APIC write races
the AVIC un-inhibition, and add a warning to catch this problem
if it re-emerges again.
V3: moved the mutex to kvm.arch and added comment
* Patch 9 is the patch from Vitaly about allowing AVIC with SYNC
as long as the guest doesn’t use the AutoEOI feature. I only slightly
changed it to expose the AutoEOI cpuid bit regardless of AVIC enablement.
* Patch 10 is a new patch in this version, which is a refactoring that is now
possible in SVM AVIC inhibition code, because the RCU lock is not dropped anymore.
* Patch 11 fixes another issue I found in AVIC inhibit code:
Currently avic_vcpu_load/avic_vcpu_put are called on userspace entry/exit
from KVM (aka kvm_vcpu_get/kvm_vcpu_put), and these functions update the
"is running" bit in the AVIC physical ID remap table and update the
target vCPU in iommu code.
However both of these functions don't do anything when AVIC is inhibited
thus the "is running" bit will be kept enabled during the exit to userspace.
This shouldn't be a big issue as the caller
doesn't use the AVIC when inhibited but still inconsistent and can trigger
a warning about this in avic_vcpu_load.
To be on the safe side I think it makes sense to call
avic_vcpu_put/avic_vcpu_load when inhibiting/uninhibiting the AVIC.
This will ensure that the work these functions do is matched.
* Patch 12 (also new in this series) removes the pointless APIC base
relocation from AVIC to make it consistent with the rest of KVM.
(both AVIC and APICv only support default base, while regular KVM,
sort of support any APIC base as long as it is not RAM.
If guest attempts to relocate APIC base to non RAM area,
while APICv/AVIC are active, the new base will be non accelerated,
while the default base will continue to be AVIC/APICv backed).
Best regards,
Maxim Levitsky
Maxim Levitsky (10):
KVM: x86/mmu: bump mmu notifier count in kvm_zap_gfn_range
KVM: x86/mmu: rename try_async_pf to kvm_faultin_pfn
KVM: x86/mmu: allow kvm_faultin_pfn to return page fault handling code
KVM: x86/mmu: allow APICv memslot to be partially enabled
KVM: x86: don't disable APICv memslot when inhibited
KVM: x86: APICv: fix race in kvm_request_apicv_update on SVM
KVM: SVM: add warning for mistmatch between AVIC state and AVIC access
page state
KVM: SVM: remove svm_toggle_avic_for_irq_window
KVM: SVM: call avic_vcpu_load/avic_vcpu_put when enabling/disabling
AVIC
KVM: SVM: AVIC: drop unsupported AVIC base relocation code
Sean Christopherson (1):
Revert "KVM: x86/mmu: Allow zap gfn range to operate under the mmu
read lock"
Vitaly Kuznetsov (1):
KVM: x86: hyper-v: Deactivate APICv only when AutoEOI feature is in
use
arch/x86/include/asm/kvm-x86-ops.h | 1 -
arch/x86/include/asm/kvm_host.h | 7 ++-
arch/x86/kvm/hyperv.c | 27 ++++++++---
arch/x86/kvm/mmu/mmu.c | 69 ++++++++++++++++----------
arch/x86/kvm/mmu/paging_tmpl.h | 6 +--
arch/x86/kvm/mmu/tdp_mmu.c | 15 ++----
arch/x86/kvm/mmu/tdp_mmu.h | 11 ++---
arch/x86/kvm/svm/avic.c | 77 ++++++++++++------------------
arch/x86/kvm/svm/svm.c | 23 +++++----
arch/x86/kvm/svm/svm.h | 8 ----
arch/x86/kvm/x86.c | 56 +++++++++++++---------
include/linux/kvm_host.h | 5 ++
virt/kvm/kvm_main.c | 7 ++-
13 files changed, 166 insertions(+), 146 deletions(-)
--
2.26.3
