On 2021/3/4 1:19, Sean Christopherson wrote:
On Wed, Mar 03, 2021, Like Xu wrote:
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 25d620685ae7..d14a14eb712d 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -19,6 +19,7 @@
#include "pmu.h"
#define MSR_PMC_FULL_WIDTH_BIT (MSR_IA32_PMC0 - MSR_IA32_PERFCTR0)
+#define KVM_ARCH_LBR_CTL_MASK 0x7f000f
It would nice to build this up with the individual bits instead of tossing in a
magic number.
I will move the mask ARCH_LBR_CTL_MASK from lbr.c to msr-index.h and thus,
#define KVM_ARCH_LBR_CTL_MASK (ARCH_LBR_CTL_MASK | ARCH_LBR_CTL_LBREN)
I assume the move operation would be a separate patch for host side.
static struct kvm_event_hw_type_mapping intel_arch_events[] = {
/* Index must match CPUID 0x0A.EBX bit vector */
@@ -221,6 +222,7 @@ static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32
msr)
ret = pmu->version > 1;
break;
case MSR_ARCH_LBR_DEPTH:
+ case MSR_ARCH_LBR_CTL:
ret = guest_cpuid_has(vcpu, X86_FEATURE_ARCH_LBR);
break;
default:
@@ -390,6 +392,9 @@ static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct
msr_data *msr_info)
case MSR_ARCH_LBR_DEPTH:
msr_info->data = lbr_desc->records.nr;
return 0;
+ case MSR_ARCH_LBR_CTL:
+ msr_info->data = vmcs_read64(GUEST_IA32_LBR_CTL);
+ return 0;
default:
if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0)) ||
(pmc = get_gp_pmc(pmu, msr, MSR_IA32_PMC0))) {
@@ -457,6 +462,15 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct
msr_data *msr_info)
lbr_desc->records.nr = data;
lbr_desc->arch_lbr_reset = true;
return 0;
+ case MSR_ARCH_LBR_CTL:
+ if (!(data & ~KVM_ARCH_LBR_CTL_MASK)) {
Maybe invert this to reduce indentation?
if (data & ...)
break; (or "return 1;")
Fine to me.
+ vmcs_write64(GUEST_IA32_LBR_CTL, data);
+ if (intel_pmu_lbr_is_enabled(vcpu) && !lbr_desc->event
&&
+ (data & ARCH_LBR_CTL_LBREN))
Alignment.
I'll fix it.
+ intel_pmu_create_guest_lbr_event(vcpu);
+ return 0;
+ }
+ break;
default:
if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0)) ||
(pmc = get_gp_pmc(pmu, msr, MSR_IA32_PMC0))) {
@@ -635,12 +649,15 @@ static void intel_pmu_reset(struct kvm_vcpu *vcpu)
*/
static void intel_pmu_legacy_freezing_lbrs_on_pmi(struct kvm_vcpu *vcpu)
{
- u64 data = vmcs_read64(GUEST_IA32_DEBUGCTL);
+ u32 lbr_ctl_field = GUEST_IA32_DEBUGCTL;
- if (data & DEBUGCTLMSR_FREEZE_LBRS_ON_PMI) {
- data &= ~DEBUGCTLMSR_LBR;
- vmcs_write64(GUEST_IA32_DEBUGCTL, data);
- }
+ if (!(vmcs_read64(GUEST_IA32_DEBUGCTL) &
DEBUGCTLMSR_FREEZE_LBRS_ON_PMI))
+ return;
+
+ if (guest_cpuid_has(vcpu, X86_FEATURE_ARCH_LBR))
+ lbr_ctl_field = GUEST_IA32_LBR_CTL;
+
+ vmcs_write64(lbr_ctl_field, vmcs_read64(lbr_ctl_field) & ~BIT(0));
Use ARCH_LBR_CTL_LBREN?
I'm trying to unify the usage of EN bit for both Arch LBR and legacy LBR:
#define ARCH_LBR_CTL_LBREN BIT(0)
#define DEBUGCTLMSR_LBR (1UL << 0)
Any suggestion ?
}
static void intel_pmu_deliver_pmi(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 6d7e760fdfa0..a0660b9934c6 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2036,6 +2036,13 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct
msr_data *msr_info)
VM_EXIT_SAVE_DEBUG_CONTROLS)
get_vmcs12(vcpu)->guest_ia32_debugctl = data;
+ /*
+ * For Arch LBR, IA32_DEBUGCTL[bit 0] has no meaning.
+ * It can be written to 0 or 1, but reads will always return 0.
+ */
+ if (guest_cpuid_has(vcpu, X86_FEATURE_ARCH_LBR))
+ data &= ~DEBUGCTLMSR_LBR;
+
vmcs_write64(GUEST_IA32_DEBUGCTL, data);
if (intel_pmu_lbr_is_enabled(vcpu) && !to_vmx(vcpu)->lbr_desc.event
&&
(data & DEBUGCTLMSR_LBR))
@@ -4463,6 +4470,8 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool
init_event)
vmcs_writel(GUEST_SYSENTER_ESP, 0);
vmcs_writel(GUEST_SYSENTER_EIP, 0);
vmcs_write64(GUEST_IA32_DEBUGCTL, 0);
+ if (cpu_has_vmx_arch_lbr())
+ vmcs_write64(GUEST_IA32_LBR_CTL, 0);
Not that any guest is likely to care, but is the MSR cleared on INIT? The SDM
has specific language for warm reset, but I can't find anything for INIT.
On a warm reset, all LBR MSRs, including IA32_LBR_DEPTH, have their values
preserved. However, IA32_LBR_CTL.LBREn is cleared to 0, disabling LBRs. If a
warm reset is triggered while the processor is in C6, also known as warm
init,
all LBR MSRs will be reset to their initial values.
I was told that the reset behavior of GUEST_IA32_LBR_CTL
would be the same as the GUEST_IA32_DEBUGCTL (true for INIT as well).
It looks we have not strictly distinguished the guest's power concept C*.
Do we have two trap paths for "warm reset" and "warm init" ?
}
kvm_set_rflags(vcpu, X86_EFLAGS_FIXED);
--
2.29.2
