KVM: VMX: disable PEBS before a guest entry

[deliverable/linux.git] / arch / x86 / kvm / vmx.c

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 0ff453749a909b9f0140b5de5d5d2dbb133e99d9..6e51493ff4f90e5cb957a617fa680f77a12e2606 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1813,6 +1813,13 @@ static void add_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);
        }
 
        for (i = 0; i < m->nr; ++i)