Commit fdd2db51 authored by Adrian Hunter's avatar Adrian Hunter Committed by Sean Christopherson
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KVM: VMX: Allow toggling bits in MSR_IA32_RTIT_CTL when enable bit is cleared 



Allow toggling other bits in MSR_IA32_RTIT_CTL if the enable bit is being
cleared, the existing logic simply ignores the enable bit.  E.g. KVM will
incorrectly reject a write of '0' to stop tracing.

Fixes: bf8c55d8 ("KVM: x86: Implement Intel PT MSRs read/write emulation")
Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
[sean: rework changelog, drop stable@]
Reviewed-by: default avatarXiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20241101185031.1799556-3-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 04bc93cf

arch/x86/kvm/vmx/vmx.c

+2 −1
Original line number Diff line number Diff line
@@ -1636,7 +1636,8 @@ static int vmx_rtit_ctl_check(struct kvm_vcpu *vcpu, u64 data) 
	 * result in a #GP unless the same write also clears TraceEn.

	 */

	if ((vmx->pt_desc.guest.ctl & RTIT_CTL_TRACEEN) &&

		((vmx->pt_desc.guest.ctl ^ data) & ~RTIT_CTL_TRACEEN))

	    (data & RTIT_CTL_TRACEEN) &&

	    data != vmx->pt_desc.guest.ctl)

		return 1;



	/*