Re: [PATCH v2] KVM: SVM: Ensure SPEC_CTRL[63:32] is context switched between guest and host
From: Sean Christopherson
Date: Mon Nov 10 2025 - 10:54:08 EST
On Thu, 06 Nov 2025 11:12:30 -0800, Sean Christopherson wrote:
> SPEC_CTRL is an MSR, i.e. a 64-bit value, but the VMRUN assembly code
> assumes bits 63:32 are always zero. The bug is _currently_ benign because
> neither KVM nor the kernel support setting any of bits 63:32, but it's
> still a bug that needs to be fixed.
Applied to kvm-x86 svm, with the comment fixups.
[1/1] KVM: SVM: Ensure SPEC_CTRL[63:32] is context switched between guest and host
https://github.com/kvm-x86/linux/commit/c331b400e291
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https://github.com/kvm-x86/linux/tree/next