[1/3,v3] KVM: nVMX: nSVM: 'nested_run' should count guest-entry attempts that make it to guest code

Commit Message

Krish Sadhukhan June 9, 2021, 1:19 a.m. UTC

Currently, the 'nested_run' statistic counts all guest-entry attempts,
including those that fail during vmentry checks on Intel and during
consistency checks on AMD. Convert this statistic to count only those
guest-entries that make it past these state checks and make it to guest
code. This will tell us the number of guest-entries that actually executed
or tried to execute guest code.

Also, rename this statistic to 'nested_runs' since it is a count.

Signed-off-by: Krish Sadhukhan <[e-mail]>
---
 arch/x86/include/asm/kvm_host.h |  2 +-
 arch/x86/kvm/svm/nested.c       |  2 --
 arch/x86/kvm/svm/svm.c          |  6 ++++++
 arch/x86/kvm/vmx/nested.c       |  2 --
 arch/x86/kvm/vmx/vmx.c          | 13 ++++++++++++-
 arch/x86/kvm/x86.c              |  2 +-
 6 files changed, 20 insertions(+), 7 deletions(-)

Patch

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 55efbacfc244..cf8557b2b90f 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1170,7 +1170,7 @@  struct kvm_vcpu_stat {
 	u64 req_event;
 	u64 halt_poll_success_ns;
 	u64 halt_poll_fail_ns;
-	u64 nested_run;
+	u64 nested_runs;
 	u64 directed_yield_attempted;
 	u64 directed_yield_successful;
 };
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 5e8d8443154e..34fc74b0d58a 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -596,8 +596,6 @@  int nested_svm_vmrun(struct kvm_vcpu *vcpu)
 	struct kvm_host_map map;
 	u64 vmcb12_gpa;
 
-	++vcpu->stat.nested_run;
-
 	if (is_smm(vcpu)) {
 		kvm_queue_exception(vcpu, UD_VECTOR);
 		return 1;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 4dd9b7856e5b..31646b5c4877 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3872,6 +3872,12 @@  static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
 	svm->next_rip = 0;
 	if (is_guest_mode(vcpu)) {
 		nested_sync_control_from_vmcb02(svm);
+
+		/* Track VMRUNs that have made past consistency checking */
+		if (svm->nested.nested_run_pending &&
+		    svm->vmcb->control.exit_code != SVM_EXIT_ERR)
+                        ++vcpu->stat.nested_runs;
+
 		svm->nested.nested_run_pending = 0;
 	}
 
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 6058a65a6ede..94f70c0af4a4 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -3454,8 +3454,6 @@  static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
 	u32 interrupt_shadow = vmx_get_interrupt_shadow(vcpu);
 	enum nested_evmptrld_status evmptrld_status;
 
-	++vcpu->stat.nested_run;
-
 	if (!nested_vmx_check_permission(vcpu))
 		return 1;
 
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index f2fd447eed45..fa8df7ab2756 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6839,7 +6839,18 @@  static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu)
 
 	kvm_load_host_xsave_state(vcpu);
 
-	vmx->nested.nested_run_pending = 0;
+	if (is_guest_mode(vcpu)) {
+		/*
+		 * Track VMLAUNCH/VMRESUME that have made past guest state
+		 * checking.
+		 */
+		if (vmx->nested.nested_run_pending &&
+		    !vmx->exit_reason.failed_vmentry)
+			++vcpu->stat.nested_runs;
+
+		vmx->nested.nested_run_pending = 0;
+	}
+
 	vmx->idt_vectoring_info = 0;
 
 	if (unlikely(vmx->fail)) {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5bd550eaf683..6d1f51f6c344 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -243,7 +243,7 @@  struct kvm_stats_debugfs_item debugfs_entries[] = {
 	VCPU_STAT("l1d_flush", l1d_flush),
 	VCPU_STAT("halt_poll_success_ns", halt_poll_success_ns),
 	VCPU_STAT("halt_poll_fail_ns", halt_poll_fail_ns),
-	VCPU_STAT("nested_run", nested_run),
+	VCPU_STAT("nested_runs", nested_runs),
 	VCPU_STAT("directed_yield_attempted", directed_yield_attempted),
 	VCPU_STAT("directed_yield_successful", directed_yield_successful),
 	VM_STAT("mmu_shadow_zapped", mmu_shadow_zapped),