[PATCH v10 022/108] KVM: TDX: Make pmu_intel.c ignore guest TD case

isaku.yamahata
2022-10-30T06:26:06Z

From: Isaku Yamahata <isaku.yamahata@intel.com>

Because TDX KVM doesn't support PMU yet (it's future work of TDX KVM
support as another patch series) and pmu_intel.c touches vmx specific
structure in vcpu initialization, as workaround add dummy structure to
struct vcpu_tdx and pmu_intel.c can ignore TDX case.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
---
arch/x86/kvm/vmx/pmu_intel.c | 46 +++++++++++++++++++++++++++++++++++-
arch/x86/kvm/vmx/pmu_intel.h | 28 ++++++++++++++++++++++
arch/x86/kvm/vmx/tdx.h | 7 ++++++
arch/x86/kvm/vmx/vmx.c | 2 +-
arch/x86/kvm/vmx/vmx.h | 32 +------------------------
5 files changed, 82 insertions(+), 33 deletions(-)
create mode 100644 arch/x86/kvm/vmx/pmu_intel.h

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 25b70a85bef5..41e97c21f0d7 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -17,6 +17,7 @@
#include "lapic.h"
#include "nested.h"
#include "pmu.h"
+#include "tdx.h"

#define MSR_PMC_FULL_WIDTH_BIT (MSR_IA32_PMC0 - MSR_IA32_PERFCTR0)

@@ -35,6 +36,26 @@ static struct kvm_event_hw_type_mapping intel_arch_events[] = {
/* mapping between fixed pmc index and intel_arch_events array */
static int fixed_pmc_events[] = {1, 0, 7};

+struct lbr_desc *vcpu_to_lbr_desc(struct kvm_vcpu *vcpu)
+{
+#ifdef CONFIG_INTEL_TDX_HOST
+ if (is_td_vcpu(vcpu))
+ return &to_tdx(vcpu)->lbr_desc;
+#endif
+
+ return &to_vmx(vcpu)->lbr_desc;
+}
+
+struct x86_pmu_lbr *vcpu_to_lbr_records(struct kvm_vcpu *vcpu)
+{
+#ifdef CONFIG_INTEL_TDX_HOST
+ if (is_td_vcpu(vcpu))
+ return &to_tdx(vcpu)->lbr_desc.records;
+#endif
+
+ return &to_vmx(vcpu)->lbr_desc.records;
+}
+
static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data)
{
struct kvm_pmc *pmc;
@@ -167,6 +188,23 @@ static inline struct kvm_pmc *get_fw_gp_pmc(struct kvm_pmu *pmu, u32 msr)
return get_gp_pmc(pmu, msr, MSR_IA32_PMC0);
}

+bool intel_pmu_lbr_is_compatible(struct kvm_vcpu *vcpu)
+{
+ if (is_td_vcpu(vcpu))
+ return false;
+ return cpuid_model_is_consistent(vcpu);
+}
+
+bool intel_pmu_lbr_is_enabled(struct kvm_vcpu *vcpu)
+{
+ struct x86_pmu_lbr *lbr = vcpu_to_lbr_records(vcpu);
+
+ if (is_td_vcpu(vcpu))
+ return false;
+
+ return lbr->nr && (vcpu_get_perf_capabilities(vcpu) & PMU_CAP_LBR_FMT);
+}
+
static bool intel_pmu_is_valid_lbr_msr(struct kvm_vcpu *vcpu, u32 index)
{
struct x86_pmu_lbr *records = vcpu_to_lbr_records(vcpu);
@@ -277,6 +315,9 @@ int intel_pmu_create_guest_lbr_event(struct kvm_vcpu *vcpu)
PERF_SAMPLE_BRANCH_USER,
};

+ if (WARN_ON_ONCE(is_td_vcpu(vcpu)))
+ return 0;
+
if (unlikely(lbr_desc->event)) {
__set_bit(INTEL_PMC_IDX_FIXED_VLBR, pmu->pmc_in_use);
return 0;
@@ -586,7 +627,7 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
INTEL_PMC_MAX_GENERIC, pmu->nr_arch_fixed_counters);

perf_capabilities = vcpu_get_perf_capabilities(vcpu);
- if (cpuid_model_is_consistent(vcpu) &&
+ if (intel_pmu_lbr_is_compatible(vcpu) &&
(perf_capabilities & PMU_CAP_LBR_FMT))
x86_perf_get_lbr(&lbr_desc->records);
else
@@ -643,6 +684,9 @@ static void intel_pmu_reset(struct kvm_vcpu *vcpu)
struct kvm_pmc *pmc = NULL;
int i;

+ if (is_td_vcpu(vcpu))
+ return;
+
for (i = 0; i < INTEL_PMC_MAX_GENERIC; i++) {
pmc = &pmu->gp_counters[i];

diff --git a/arch/x86/kvm/vmx/pmu_intel.h b/arch/x86/kvm/vmx/pmu_intel.h
new file mode 100644
index 000000000000..66bba47c1269
--- /dev/null
+++ b/arch/x86/kvm/vmx/pmu_intel.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __KVM_X86_VMX_PMU_INTEL_H
+#define __KVM_X86_VMX_PMU_INTEL_H
+
+struct lbr_desc *vcpu_to_lbr_desc(struct kvm_vcpu *vcpu);
+struct x86_pmu_lbr *vcpu_to_lbr_records(struct kvm_vcpu *vcpu);
+
+bool intel_pmu_lbr_is_compatible(struct kvm_vcpu *vcpu);
+bool intel_pmu_lbr_is_enabled(struct kvm_vcpu *vcpu);
+int intel_pmu_create_guest_lbr_event(struct kvm_vcpu *vcpu);
+
+struct lbr_desc {
+ /* Basic info about guest LBR records. */
+ struct x86_pmu_lbr records;
+
+ /*
+ * Emulate LBR feature via passthrough LBR registers when the
+ * per-vcpu guest LBR event is scheduled on the current pcpu.
+ *
+ * The records may be inaccurate if the host reclaims the LBR.
+ */
+ struct perf_event *event;
+
+ /* True if LBRs are marked as not intercepted in the MSR bitmap */
+ bool msr_passthrough;
+};
+
+#endif /* __KVM_X86_VMX_PMU_INTEL_H */
diff --git a/arch/x86/kvm/vmx/tdx.h b/arch/x86/kvm/vmx/tdx.h
index ff0ea9cad347..5aea69716278 100644
--- a/arch/x86/kvm/vmx/tdx.h
+++ b/arch/x86/kvm/vmx/tdx.h
@@ -4,6 +4,7 @@

#ifdef CONFIG_INTEL_TDX_HOST

+#include "pmu_intel.h"
#include "tdx_ops.h"

struct tdx_td_page {
@@ -30,6 +31,12 @@ struct vcpu_tdx {

struct tdx_td_page tdvpr;
struct tdx_td_page *tdvpx;
+
+ /*
+ * Dummy to make pmu_intel not corrupt memory.
+ * TODO: Support PMU for TDX. Future work.
+ */
+ struct lbr_desc lbr_desc;
};

static inline bool is_td(struct kvm *kvm)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 68aef67c5eb7..f890191e8580 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2341,7 +2341,7 @@ int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
if ((data & PMU_CAP_LBR_FMT) !=
(vmx_get_perf_capabilities() & PMU_CAP_LBR_FMT))
return 1;
- if (!cpuid_model_is_consistent(vcpu))
+ if (!intel_pmu_lbr_is_compatible(vcpu))
return 1;
}
if (data & PERF_CAP_PEBS_FORMAT) {
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index a3da84f4ea45..d49d0ace9fb8 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -11,6 +11,7 @@
#include "capabilities.h"
#include "../kvm_cache_regs.h"
#include "posted_intr.h"
+#include "pmu_intel.h"
#include "vmcs.h"
#include "vmx_ops.h"
#include "../cpuid.h"
@@ -105,22 +106,6 @@ static inline bool intel_pmu_has_perf_global_ctrl(struct kvm_pmu *pmu)
return pmu->version > 1;
}

-struct lbr_desc {
- /* Basic info about guest LBR records. */
- struct x86_pmu_lbr records;
-
- /*
- * Emulate LBR feature via passthrough LBR registers when the
- * per-vcpu guest LBR event is scheduled on the current pcpu.
- *
- * The records may be inaccurate if the host reclaims the LBR.
- */
- struct perf_event *event;
-
- /* True if LBRs are marked as not intercepted in the MSR bitmap */
- bool msr_passthrough;
-};
-
/*
* The nested_vmx structure is part of vcpu_vmx, and holds information we need
* for correct emulation of VMX (i.e., nested VMX) on this vcpu.
@@ -650,21 +635,6 @@ static inline struct vcpu_vmx *to_vmx(struct kvm_vcpu *vcpu)
return container_of(vcpu, struct vcpu_vmx, vcpu);
}

-static inline struct lbr_desc *vcpu_to_lbr_desc(struct kvm_vcpu *vcpu)
-{
- return &to_vmx(vcpu)->lbr_desc;
-}
-
-static inline struct x86_pmu_lbr *vcpu_to_lbr_records(struct kvm_vcpu *vcpu)
-{
- return &vcpu_to_lbr_desc(vcpu)->records;
-}
-
-static inline bool intel_pmu_lbr_is_enabled(struct kvm_vcpu *vcpu)
-{
- return !!vcpu_to_lbr_records(vcpu)->nr;
-}
-
void intel_pmu_cross_mapped_check(struct kvm_pmu *pmu);
int intel_pmu_create_guest_lbr_event(struct kvm_vcpu *vcpu);
void vmx_passthrough_lbr_msrs(struct kvm_vcpu *vcpu);
--
2.25.1