2016-03-03 13:32-0800, David Matlack: > On Thu, Mar 3, 2016 at 10:53 AM, Radim Krčmář <rkrcmar@xxxxxxxxxx> wrote: >> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >> @@ -1767,6 +1767,13 @@ static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr) >> return; >> } >> break; >> + case MSR_IA32_PEBS_ENABLE: >> + /* PEBS needs a quiescent period after being disabled (to write >> + * a record). Disabling PEBS through VMX MSR swapping doesn't >> + * provide that period, so a CPU could write host's record into >> + * guest's memory. >> + */ >> + wrmsrl(MSR_IA32_PEBS_ENABLE, 0); > > Should this go in add_atomic_switch_msr instead of clear_atomic_switch_msr? Yes, it could be cleared in both (in case guest PEBS can be non-zero), but I wanted to have it only in add_atomic_switch_msr(). Thank you! v2 underway. (In case it makes you wonder how it was tested: I have a bad habit of trying whether a patch can be improved before posting and this one went awry, because I already returned the machine with reproducer and the change seemed simple enough.) -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html