linux-kernel - [PATCH 0/2] KVM: x86: Revert to fix apic_hw

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Message-Id: <20211013003554.47705-1-seanjc@google.com>
Date:   Tue, 12 Oct 2021 17:35:52 -0700
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,
        syzbot+9fc046ab2b0cf295a063@...kaller.appspotmail.com,
        Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>
Subject: [PATCH 0/2] KVM: x86: Revert to fix apic_hw_disabled underflow

Revert (mostly) a patch from the vCPU RESET cleanup that open coded some
APIC shenanigans to avoid stuffing vcpu->arch.apic_base at vCPU creation,
and completely overlooked the side effects on apic_hw_disabled.  I went
for a revert as I think the original behavior is the least awful solution,
just somewhat poorly documented.

The second patch adds WARNs to detect "overflow", where "overflow" means
KVM incorrectly increments apic_hw_disabled.

Sean Christopherson (2):
  Revert "KVM: x86: Open code necessary bits of kvm_lapic_set_base() at
    vCPU RESET"
  KVM: x86: WARN if APIC HW/SW disable static keys are non-zero on
    unload

 arch/x86/kvm/lapic.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

-- 
2.33.0.1079.g6e70778dc9-goog