linux-kernel - [PATCH v2 0/4] KVM: x86: APICv fixes

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Message-Id: <20220420013732.3308816-1-seanjc@google.com>
Date:   Wed, 20 Apr 2022 01:37:28 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Maxim Levitsky <mlevitsk@...hat.com>,
        Gaoning Pan <pgn@....edu.cn>, Yongkang Jia <kangel@....edu.cn>
Subject: [PATCH v2 0/4] KVM: x86: APICv fixes

Patch 1 is brown paper bag fix for a copy+paste bug (thankfully from this
cycle).

Patch 2 fixes a nVMX + APICv bug where KVM essentially corrupts vmcs02 if
an APICv update arrives while L2 is running.  Found when testing a slight
variation of patch 3.

Patch 3 fixes a race where an APICv update that occurs while a vCPU is
being created will fail to notify that vCPU due it not yet being visible
to the updater.

Patch 4 is a minor optimization/cleanup found by inspection when digging
into everything else.

v2:
  - Collect reviews. [Maxim]
  - Reword patch 2's changelog to make it clear that ignoring vmcs02
    is perfectly ok. [Maxim]

v1: https://lore.kernel.org/all/20220416034249.2609491-3-seanjc@google.com

Sean Christopherson (4):
  KVM: x86: Tag APICv DISABLE inhibit, not ABSENT, if APICv is disabled
  KVM: nVMX: Defer APICv updates while L2 is active until L1 is active
  KVM: x86: Pend KVM_REQ_APICV_UPDATE during vCPU creation to fix a race
  KVM: x86: Skip KVM_GUESTDBG_BLOCKIRQ APICv update if APICv is disabled

 arch/x86/kvm/vmx/nested.c |  5 +++++
 arch/x86/kvm/vmx/vmx.c    |  5 +++++
 arch/x86/kvm/vmx/vmx.h    |  1 +
 arch/x86/kvm/x86.c        | 20 ++++++++++++++++++--
 4 files changed, 29 insertions(+), 2 deletions(-)


base-commit: 150866cd0ec871c765181d145aa0912628289c8a
-- 
2.36.0.rc0.470.gd361397f0d-goog