Re: [PATCH v4 0/4] KVM: x86: Fix and harden reg caching from !TASK context
From: Sean Christopherson
Date: Thu Oct 31 2024 - 15:56:37 EST
On Wed, 09 Oct 2024 10:49:58 -0700, Sean Christopherson wrote:
> Fix a (VMX only) bug reported by Maxim where KVM caches a stale SS.AR_BYTES
> when involuntary preemption schedules out a vCPU during vmx_vcpu_rest(), and
> ultimately clobbers the VMCS's SS.AR_BYTES if userspace does KVM_GET_SREGS
> => KVM_SET_SREGS, i.e. if userspace writes the stale value back into KVM.
>
> v4, as this is a spiritual successor to Maxim's earlier series.
>
> [...]
Applied 1 and 3-4 to kvm-x86 misc. Patch 2 went into 6.12. Thanks!
[1/4] KVM: x86: Bypass register cache when querying CPL from kvm_sched_out()
https://github.com/kvm-x86/linux/commit/8c8e90f79c56
[2/4] KVM: VMX: reset the segment cache after segment init in vmx_vcpu_reset()
(no commit info)
[3/4] KVM: x86: Add lockdep-guarded asserts on register cache usage
https://github.com/kvm-x86/linux/commit/21abefc6958d
[4/4] KVM: x86: Use '0' for guest RIP if PMI encounters protected guest state
https://github.com/kvm-x86/linux/commit/a395d143ef40
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https://github.com/kvm-x86/linux/tree/next