From: Joerg Roedel <[EMAIL PROTECTED]>
This patch implements the Last Branch Record Virtualization (LBRV) feature of
the AMD Barcelona and Phenom processors into the kvm-amd module. It will only
be enabled if the guest enables last branch recording in the DEBUG_CTL MSR. So
there is no increased world switch overhead when the guest doesn't use these
MSRs.
Signed-off-by: Joerg Roedel <[EMAIL PROTECTED]>
Signed-off-by: Markus Rechberger <[EMAIL PROTECTED]>
Signed-off-by: Avi Kivity <[EMAIL PROTECTED]>
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 3b31162..e1d139f 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -47,6 +47,8 @@ MODULE_LICENSE("GPL");
#define SVM_FEATURE_LBRV (1 << 1)
#define SVM_DEATURE_SVML (1 << 2)
+#define DEBUGCTL_RESERVED_BITS (~(0x3fULL))
+
/* enable NPT for AMD64 and X86 with PAE */
#if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
static bool npt_enabled = true;
@@ -387,6 +389,28 @@ static void svm_vcpu_init_msrpm(u32 *msrpm)
set_msr_interception(msrpm, MSR_IA32_SYSENTER_EIP, 1, 1);
}
+static void svm_enable_lbrv(struct vcpu_svm *svm)
+{
+ u32 *msrpm = svm->msrpm;
+
+ svm->vmcb->control.lbr_ctl = 1;
+ set_msr_interception(msrpm, MSR_IA32_LASTBRANCHFROMIP, 1, 1);
+ set_msr_interception(msrpm, MSR_IA32_LASTBRANCHTOIP, 1, 1);
+ set_msr_interception(msrpm, MSR_IA32_LASTINTFROMIP, 1, 1);
+ set_msr_interception(msrpm, MSR_IA32_LASTINTTOIP, 1, 1);
+}
+
+static void svm_disable_lbrv(struct vcpu_svm *svm)
+{
+ u32 *msrpm = svm->msrpm;
+
+ svm->vmcb->control.lbr_ctl = 0;
+ set_msr_interception(msrpm, MSR_IA32_LASTBRANCHFROMIP, 0, 0);
+ set_msr_interception(msrpm, MSR_IA32_LASTBRANCHTOIP, 0, 0);
+ set_msr_interception(msrpm, MSR_IA32_LASTINTFROMIP, 0, 0);
+ set_msr_interception(msrpm, MSR_IA32_LASTINTTOIP, 0, 0);
+}
+
static __init int svm_hardware_setup(void)
{
int cpu;
@@ -1231,8 +1255,19 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, unsigned
ecx, u64 data)
svm->vmcb->save.sysenter_esp = data;
break;
case MSR_IA32_DEBUGCTLMSR:
- pr_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTLMSR 0x%llx, nop\n",
- __FUNCTION__, data);
+ if (!svm_has(SVM_FEATURE_LBRV)) {
+ pr_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTL 0x%llx, nop\n",
+ __FUNCTION__, data);
+ break;
+ }
+ if (data & DEBUGCTL_RESERVED_BITS)
+ return 1;
+
+ svm->vmcb->save.dbgctl = data;
+ if (data & (1ULL<<0))
+ svm_enable_lbrv(svm);
+ else
+ svm_disable_lbrv(svm);
break;
case MSR_K7_EVNTSEL0:
case MSR_K7_EVNTSEL1:
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