Re: [PATCH] KVM: x86/pmu: Disable support for adaptive PEBS

From: Sean Christopherson
Date: Mon Apr 08 2024 - 22:03:39 EST


On Wed, 06 Mar 2024 16:58:33 -0800, Sean Christopherson wrote:
> Drop support for virtualizing adaptive PEBS, as KVM's implementation is
> architecturally broken without an obvious/easy path forward, and because
> exposing adaptive PEBS can leak host LBRs to the guest, i.e. can leak
> host kernel addresses to the guest.
>
> Bug #1 is that KVM doesn't doesn't account for the upper 32 bits of
> IA32_FIXED_CTR_CTRL when (re)programming fixed counters, e.g
> fixed_ctrl_field() drops the upper bits, reprogram_fixed_counters()
> stores local variables as u8s and truncates the upper bits too, etc.
>
> [...]

Applied to kvm-x86 fixes, thanks!

[1/1] KVM: x86/pmu: Disable support for adaptive PEBS
https://github.com/kvm-x86/linux/commit/9e985cbf2942

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https://github.com/kvm-x86/linux/tree/next