Re: [PATCH 0/4] KVM: x86: Fix WFS vs. pending SMI WARN

[Sean Christopherson]

On Thu, 05 Jun 2025 12:50:14 -0700, Sean Christopherson wrote:
> Fix a user-triggerable WARN that syzkaller found by stuffing INIT_RECEIVED,
> a.k.a. WFS, and then putting the vCPU into VMX Root Mode (post-VMXON).  Use
> the same approach KVM uses for dealing with "impossible" emulation when
> running a !URG guest, and simply wait until KVM_RUN to detect that the vCPU
> has architecturally impossible state.
> 
> Sean Christopherson (4):
>   KVM: x86: Drop pending_smi vs. INIT_RECEIVED check when setting
>     MP_STATE
>   KVM: x86: WARN and reject KVM_RUN if vCPU's MP_STATE is SIPI_RECEIVED
>   KVM: x86: Move INIT_RECEIVED vs. INIT/SIPI blocked check to KVM_RUN
>   KVM: x86: Refactor handling of SIPI_RECEIVED when setting MP_STATE
> 
> [...]

Applied to kvm-x86 misc, thanks!

[1/4] KVM: x86: Drop pending_smi vs. INIT_RECEIVED check when setting MP_STATE
      https://github.com/kvm-x86/linux/commit/c4a37acc5193
[2/4] KVM: x86: WARN and reject KVM_RUN if vCPU's MP_STATE is SIPI_RECEIVED
      https://github.com/kvm-x86/linux/commit/16777ebded41
[3/4] KVM: x86: Move INIT_RECEIVED vs. INIT/SIPI blocked check to KVM_RUN
      https://github.com/kvm-x86/linux/commit/0fe3e8d804fd
[4/4] KVM: x86: Refactor handling of SIPI_RECEIVED when setting MP_STATE
      https://github.com/kvm-x86/linux/commit/58c81bc1e71d

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https://github.com/kvm-x86/kvm-unit-tests/tree/next