[PATCH 1/2] KVM: stats: Add counters for VMX all/L2/nested exit reasons

[Jing Zhang <jingzhangos@google.com>]

These stats will be used to monitor the nested virtualization use in
VMs. Most importantly: VMXON exits are evidence that the guest has
enabled VMX, VMLAUNCH/VMRESUME exits are evidence that the guest has run
an L2.

Original-by: Peter Feiner <pfeiner@google.com>
Signed-off-by: Jing Zhang <jingzhangos@google.com>
---
 arch/x86/include/asm/kvm_host.h | 4 ++++
 arch/x86/include/uapi/asm/vmx.h | 1 +
 arch/x86/kvm/vmx/vmx.c          | 7 ++++++-
 arch/x86/kvm/x86.c              | 5 ++++-
 include/linux/kvm_host.h        | 4 ++++
 5 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 09b256db394a..dd2380c9ea96 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -34,6 +34,7 @@
 #include <asm/kvm_page_track.h>
 #include <asm/kvm_vcpu_regs.h>
 #include <asm/hyperv-tlfs.h>
+#include <asm/vmx.h>
 
 #define __KVM_HAVE_ARCH_VCPU_DEBUGFS
 
@@ -1257,6 +1258,9 @@ struct kvm_vcpu_stat {
 	u64 directed_yield_attempted;
 	u64 directed_yield_successful;
 	u64 guest_mode;
+	u64 vmx_all_exits[EXIT_REASON_NUM];
+	u64 vmx_l2_exits[EXIT_REASON_NUM];
+	u64 vmx_nested_exits[EXIT_REASON_NUM];
 };
 
 struct x86_instruction_info;
diff --git a/arch/x86/include/uapi/asm/vmx.h b/arch/x86/include/uapi/asm/vmx.h
index 946d761adbd3..563b3901ef7a 100644
--- a/arch/x86/include/uapi/asm/vmx.h
+++ b/arch/x86/include/uapi/asm/vmx.h
@@ -91,6 +91,7 @@
 #define EXIT_REASON_UMWAIT              67
 #define EXIT_REASON_TPAUSE              68
 #define EXIT_REASON_BUS_LOCK            74
+#define EXIT_REASON_NUM                 (EXIT_REASON_BUS_LOCK + 1)
 
 #define VMX_EXIT_REASONS \
 	{ EXIT_REASON_EXCEPTION_NMI,         "EXCEPTION_NMI" }, \
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index fada1055f325..5cd9f02a458a 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5890,6 +5890,8 @@ static int __vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
 	u32 vectoring_info = vmx->idt_vectoring_info;
 	u16 exit_handler_index;
 
+	++vcpu->stat.vmx_all_exits[exit_reason.basic];
+
 	/*
 	 * Flush logged GPAs PML buffer, this will make dirty_bitmap more
 	 * updated. Another good is, in kvm_vm_ioctl_get_dirty_log, before
@@ -5915,6 +5917,7 @@ static int __vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
 		return handle_invalid_guest_state(vcpu);
 
 	if (is_guest_mode(vcpu)) {
+		++vcpu->stat.vmx_l2_exits[exit_reason.basic];
 		/*
 		 * PML is never enabled when running L2, bail immediately if a
 		 * PML full exit occurs as something is horribly wrong.
@@ -5935,8 +5938,10 @@ static int __vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
 		 */
 		nested_mark_vmcs12_pages_dirty(vcpu);
 
-		if (nested_vmx_reflect_vmexit(vcpu))
+		if (nested_vmx_reflect_vmexit(vcpu)) {
+			++vcpu->stat.vmx_nested_exits[exit_reason.basic];
 			return 1;
+		}
 	}
 
 	if (exit_reason.failed_vmentry) {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 86539c1686fa..245ad1d147dd 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -277,7 +277,10 @@ const struct _kvm_stats_desc kvm_vcpu_stats_desc[] = {
 	STATS_DESC_COUNTER(VCPU, nested_run),
 	STATS_DESC_COUNTER(VCPU, directed_yield_attempted),
 	STATS_DESC_COUNTER(VCPU, directed_yield_successful),
-	STATS_DESC_ICOUNTER(VCPU, guest_mode)
+	STATS_DESC_ICOUNTER(VCPU, guest_mode),
+	STATS_DESC_LINHIST_COUNTER(VCPU, vmx_all_exits, EXIT_REASON_NUM, 1),
+	STATS_DESC_LINHIST_COUNTER(VCPU, vmx_l2_exits, EXIT_REASON_NUM, 1),
+	STATS_DESC_LINHIST_COUNTER(VCPU, vmx_nested_exits, EXIT_REASON_NUM, 1),
 };
 
 const struct kvm_stats_header kvm_vcpu_stats_header = {
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index e4d712e9f760..47e986450b06 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1429,6 +1429,10 @@ struct _kvm_stats_desc {
 #define STATS_DESC_PCOUNTER(SCOPE, name)				       \
 	STATS_DESC_PEAK(SCOPE, name, KVM_STATS_UNIT_NONE,		       \
 		KVM_STATS_BASE_POW10, 0)
+/* Linear histogram for counter */
+#define STATS_DESC_LINHIST_COUNTER(SCOPE, name, sz, bsz)		       \
+	STATS_DESC_LINEAR_HIST(SCOPE, name, KVM_STATS_UNIT_NONE,	       \
+		KVM_STATS_BASE_POW10, 0, sz, bsz)
 
 /* Cumulative time in nanosecond */
 #define STATS_DESC_TIME_NSEC(SCOPE, name)				       \

base-commit: 680c7e3be6a3d502248771fe42c911f99d7e006c
-- 
2.33.0.259.gc128427fd7-goog