[v2,20/25] KVM: TDX: Make pmu_intel.c ignore guest TD case

Commit Message

Rick Edgecombe Oct. 30, 2024, 7 p.m. UTC

From: Isaku Yamahata <[e-mail]>

TDX KVM doesn't support PMU yet, it's future work of TDX KVM support as
another patch series. For now, handle TDX by updating vcpu_to_lbr_desc()
and vcpu_to_lbr_records() to return NULL.

Signed-off-by: Isaku Yamahata <[e-mail]>
Co-developed-by: Tony Lindgren <[e-mail]>
Signed-off-by: Tony Lindgren <[e-mail]>
Signed-off-by: Rick Edgecombe <[e-mail]>
---
uAPI breakout v2:
 - Make vcpu_to_lbr_desc() to return NULL (Paolo)
 - Drop unecessary ifdefs around is_td_vcpu() (Tony)

uAPI breakout v1:
 - Fix bisectability issues in headers (Kai)
 - Fix rebase error from v19 (Chao Gao)
 - Make helpers static (Tony Lindgren)
 - Improve whitespace (Tony Lindgren)

v18:
 - Removed unnecessary change to vmx.c which caused kernel warning.
---
 arch/x86/kvm/vmx/pmu_intel.c | 50 +++++++++++++++++++++++++++++++++++-
 arch/x86/kvm/vmx/pmu_intel.h | 28 ++++++++++++++++++++
 arch/x86/kvm/vmx/vmx.h       | 34 +-----------------------
 3 files changed, 78 insertions(+), 34 deletions(-)
 create mode 100644 arch/x86/kvm/vmx/pmu_intel.h

Patch

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 83382a4d1d66..1cd92b43f463 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -19,6 +19,7 @@ 
 #include "lapic.h"
 #include "nested.h"
 #include "pmu.h"
+#include "tdx.h"
 
 /*
  * Perf's "BASE" is wildly misleading, architectural PMUs use bits 31:16 of ECX
@@ -34,6 +35,22 @@ 
 
 #define MSR_PMC_FULL_WIDTH_BIT      (MSR_IA32_PMC0 - MSR_IA32_PERFCTR0)
 
+static struct lbr_desc *vcpu_to_lbr_desc(struct kvm_vcpu *vcpu)
+{
+	if (is_td_vcpu(vcpu))
+		return NULL;
+
+	return &to_vmx(vcpu)->lbr_desc;
+}
+
+static struct x86_pmu_lbr *vcpu_to_lbr_records(struct kvm_vcpu *vcpu)
+{
+	if (is_td_vcpu(vcpu))
+		return NULL;
+
+	return &to_vmx(vcpu)->lbr_desc.records;
+}
+
 static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data)
 {
 	struct kvm_pmc *pmc;
@@ -129,6 +146,22 @@  static inline struct kvm_pmc *get_fw_gp_pmc(struct kvm_pmu *pmu, u32 msr)
 	return get_gp_pmc(pmu, msr, MSR_IA32_PMC0);
 }
 
+static 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)
+{
+	if (is_td_vcpu(vcpu))
+		return false;
+
+	return !!vcpu_to_lbr_records(vcpu)->nr;
+}
+
 static bool intel_pmu_is_valid_lbr_msr(struct kvm_vcpu *vcpu, u32 index)
 {
 	struct x86_pmu_lbr *records = vcpu_to_lbr_records(vcpu);
@@ -194,6 +227,9 @@  static inline void intel_pmu_release_guest_lbr_event(struct kvm_vcpu *vcpu)
 {
 	struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);
 
+	if (!lbr_desc)
+		return;
+
 	if (lbr_desc->event) {
 		perf_event_release_kernel(lbr_desc->event);
 		lbr_desc->event = NULL;
@@ -235,6 +271,9 @@  int intel_pmu_create_guest_lbr_event(struct kvm_vcpu *vcpu)
 					PERF_SAMPLE_BRANCH_USER,
 	};
 
+	if (WARN_ON_ONCE(!lbr_desc))
+		return 0;
+
 	if (unlikely(lbr_desc->event)) {
 		__set_bit(INTEL_PMC_IDX_FIXED_VLBR, pmu->pmc_in_use);
 		return 0;
@@ -466,6 +505,9 @@  static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
 	u64 perf_capabilities;
 	u64 counter_rsvd;
 
+	if (!lbr_desc)
+		return;
+
 	memset(&lbr_desc->records, 0, sizeof(lbr_desc->records));
 
 	/*
@@ -542,7 +584,7 @@  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))
 		memcpy(&lbr_desc->records, &vmx_lbr_caps, sizeof(vmx_lbr_caps));
 	else
@@ -570,6 +612,9 @@  static void intel_pmu_init(struct kvm_vcpu *vcpu)
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 	struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);
 
+	if (!lbr_desc)
+		return;
+
 	for (i = 0; i < KVM_MAX_NR_INTEL_GP_COUNTERS; i++) {
 		pmu->gp_counters[i].type = KVM_PMC_GP;
 		pmu->gp_counters[i].vcpu = vcpu;
@@ -677,6 +722,9 @@  void vmx_passthrough_lbr_msrs(struct kvm_vcpu *vcpu)
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 	struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);
 
+	if (WARN_ON_ONCE(!lbr_desc))
+		return;
+
 	if (!lbr_desc->event) {
 		vmx_disable_lbr_msrs_passthrough(vcpu);
 		if (vmcs_read64(GUEST_IA32_DEBUGCTL) & DEBUGCTLMSR_LBR)
diff --git a/arch/x86/kvm/vmx/pmu_intel.h b/arch/x86/kvm/vmx/pmu_intel.h
new file mode 100644
index 000000000000..5620d0882cdc
--- /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
+
+#include <linux/kvm_host.h>
+
+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;
+};
+
+extern struct x86_pmu_lbr vmx_lbr_caps;
+
+#endif /* __KVM_X86_VMX_PMU_INTEL_H */
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index ad9efe41e691..37a555c6dfbf 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 "pmu_intel.h"
 #include "vmcs.h"
 #include "vmx_ops.h"
 #include "../cpuid.h"
@@ -90,24 +91,6 @@  union vmx_exit_reason {
 	u32 full;
 };
 
-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;
-};
-
-extern struct x86_pmu_lbr vmx_lbr_caps;
-
 /*
  * 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.
@@ -659,21 +642,6 @@  static __always_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);