[PATCH 0/7] KVM: x86: Tracepoint improvements and fixes

[PATCH 0/7] KVM: x86: Tracepoint improvements and fixes

[Sean Christopherson]

Various improvements and fixes for the kvm_entry, kvm_exit and
kvm_nested_vmexit tracepoints.

  1. Capture the guest's RIP during kvm_entry for obvious reasons.

  2. Extend kvm_exit to report the same info as kvm_nested_vmexit, and
     macrofy its definition to reuse it verbatim for nested exits.

  3. Stop passing in params to kvm_nested_vmexit, and instead use the
     same approach (and now code) as kvm_exit where the tracepoint uses a
     dedicated kvm_x86_ops hook to retrieve the info.

  4. Stop reading GUEST_RIP, EXIT_QUAL, INTR_INFO, and ERROR_CODE on
     every VM-Exit from L2 (some of this comes in #3).  This saves ~100
     cycles (150+ with retpolines) on VM-Exits from L2 that are handled
     by L0, e.g. hardware interrupts.

Sean Christopherson (7):
  KVM: x86: Add RIP to the kvm_entry, i.e. VM-Enter, tracepoint
  KVM: x86: Read guest RIP from within the kvm_nested_vmexit tracepoint
  KVM: VMX: Add a helper to test for a valid error code given an intr
    info
  KVM: x86: Add intr/vectoring info and error code to kvm_exit
    tracepoint
  KVM: x86: Add macro wrapper for defining kvm_exit tracepoint
  KVM: x86: Use common definition for kvm_nested_vmexit tracepoint
  KVM: nVMX: Read EXIT_QUAL and INTR_INFO only when needed for nested
    exit

 arch/x86/include/asm/kvm_host.h |   7 ++-
 arch/x86/kvm/svm/svm.c          |  16 ++---
 arch/x86/kvm/trace.h            | 107 +++++++++++++-------------------
 arch/x86/kvm/vmx/nested.c       |  14 ++---
 arch/x86/kvm/vmx/vmcs.h         |   7 +++
 arch/x86/kvm/vmx/vmx.c          |  18 +++++-
 arch/x86/kvm/x86.c              |   2 +-
 7 files changed, 86 insertions(+), 85 deletions(-)

-- 
2.26.0

[PATCH 1/7] KVM: x86: Add RIP to the kvm_entry, i.e. VM-Enter, tracepoint

[Sean Christopherson]

Add RIP to the kvm_entry tracepoint to help debug if the kvm_exit
tracepoint is disable or if VM-Enter fails, in which case the kvm_exit
tracepoint won't be hit.

Read RIP from within the tracepoint itself to avoid a potential VMREAD
and retpoline if the guest's RIP isn't available.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/trace.h | 10 ++++++----
 arch/x86/kvm/x86.c   |  2 +-
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index b66432b015d2e..9899ff0fa2534 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -15,18 +15,20 @@
  * Tracepoint for guest mode entry.
  */
 TRACE_EVENT(kvm_entry,
-	TP_PROTO(unsigned int vcpu_id),
-	TP_ARGS(vcpu_id),
+	TP_PROTO(struct kvm_vcpu *vcpu),
+	TP_ARGS(vcpu),
 
 	TP_STRUCT__entry(
 		__field(	unsigned int,	vcpu_id		)
+		__field(	unsigned long,	rip		)
 	),
 
 	TP_fast_assign(
-		__entry->vcpu_id	= vcpu_id;
+		__entry->vcpu_id        = vcpu->vcpu_id;
+		__entry->rip		= kvm_rip_read(vcpu);
 	),
 
-	TP_printk("vcpu %u", __entry->vcpu_id)
+	TP_printk("vcpu %u, rip 0x%lx", __entry->vcpu_id, __entry->rip)
 );
 
 /*
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5f526d94c33f3..3563359316d64 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8547,7 +8547,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 		kvm_x86_ops.request_immediate_exit(vcpu);
 	}
 
-	trace_kvm_entry(vcpu->vcpu_id);
+	trace_kvm_entry(vcpu);
 
 	fpregs_assert_state_consistent();
 	if (test_thread_flag(TIF_NEED_FPU_LOAD))
-- 
2.26.0

[PATCH 2/7] KVM: x86: Read guest RIP from within the kvm_nested_vmexit tracepoint

[Sean Christopherson]

Use kvm_rip_read() to read the guest's RIP for the nested VM-Exit
tracepoint instead of having the caller pass in the tracepoint.  Params
that are passed into a tracepoint are evaluated even if the tracepoint
is disabled, i.e. passing in RIP for VMX incurs a VMREAD and retpoline
to retrieve a value that may never be used, e.g. if the exit is due to a
hardware interrupt.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/svm/svm.c    | 2 +-
 arch/x86/kvm/trace.h      | 6 +++---
 arch/x86/kvm/vmx/nested.c | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 783330d0e7b88..1fea39ff33077 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2943,7 +2943,7 @@ static int handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
 	if (is_guest_mode(vcpu)) {
 		int vmexit;
 
-		trace_kvm_nested_vmexit(svm->vmcb->save.rip, exit_code,
+		trace_kvm_nested_vmexit(vcpu, exit_code,
 					svm->vmcb->control.exit_info_1,
 					svm->vmcb->control.exit_info_2,
 					svm->vmcb->control.exit_int_info,
diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index 9899ff0fa2534..00e567378ae1f 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -571,10 +571,10 @@ TRACE_EVENT(kvm_nested_intercepts,
  * Tracepoint for #VMEXIT while nested
  */
 TRACE_EVENT(kvm_nested_vmexit,
-	    TP_PROTO(__u64 rip, __u32 exit_code,
+	    TP_PROTO(struct kvm_vcpu *vcpu, __u32 exit_code,
 		     __u64 exit_info1, __u64 exit_info2,
 		     __u32 exit_int_info, __u32 exit_int_info_err, __u32 isa),
-	    TP_ARGS(rip, exit_code, exit_info1, exit_info2,
+	    TP_ARGS(vcpu, exit_code, exit_info1, exit_info2,
 		    exit_int_info, exit_int_info_err, isa),
 
 	TP_STRUCT__entry(
@@ -588,7 +588,7 @@ TRACE_EVENT(kvm_nested_vmexit,
 	),
 
 	TP_fast_assign(
-		__entry->rip			= rip;
+		__entry->rip			= kvm_rip_read(vcpu);
 		__entry->exit_code		= exit_code;
 		__entry->exit_info1		= exit_info1;
 		__entry->exit_info2		= exit_info2;
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 4d561edf6f9ca..6f81097cbc794 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -5912,7 +5912,7 @@ bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu)
 	exit_intr_info = vmx_get_intr_info(vcpu);
 	exit_qual = vmx_get_exit_qual(vcpu);
 
-	trace_kvm_nested_vmexit(kvm_rip_read(vcpu), exit_reason, exit_qual,
+	trace_kvm_nested_vmexit(vcpu, exit_reason, exit_qual,
 				vmx->idt_vectoring_info, exit_intr_info,
 				vmcs_read32(VM_EXIT_INTR_ERROR_CODE),
 				KVM_ISA_VMX);
-- 
2.26.0

[PATCH 3/7] KVM: VMX: Add a helper to test for a valid error code given an intr info

[Sean Christopherson]

Add a helper, is_exception_with_error_code(), to provide the simple but
difficult to read code of checking for a valid exception with an error
code given a vmcs.VM_EXIT_INTR_INFO value.  The helper will gain another
user, vmx_get_exit_info(), in a future patch.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/vmx/nested.c | 4 +---
 arch/x86/kvm/vmx/vmcs.h   | 7 +++++++
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 6f81097cbc794..fc70644b916ca 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -5931,9 +5931,7 @@ bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu)
 	 * need to be synthesized by querying the in-kernel LAPIC, but external
 	 * interrupts are never reflected to L1 so it's a non-issue.
 	 */
-	if ((exit_intr_info &
-	     (INTR_INFO_VALID_MASK | INTR_INFO_DELIVER_CODE_MASK)) ==
-	    (INTR_INFO_VALID_MASK | INTR_INFO_DELIVER_CODE_MASK)) {
+	if (is_exception_with_error_code(exit_intr_info)) {
 		struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
 
 		vmcs12->vm_exit_intr_error_code =
diff --git a/arch/x86/kvm/vmx/vmcs.h b/arch/x86/kvm/vmx/vmcs.h
index 7a3675fddec20..1472c6c376f74 100644
--- a/arch/x86/kvm/vmx/vmcs.h
+++ b/arch/x86/kvm/vmx/vmcs.h
@@ -138,6 +138,13 @@ static inline bool is_external_intr(u32 intr_info)
 	return is_intr_type(intr_info, INTR_TYPE_EXT_INTR);
 }
 
+static inline bool is_exception_with_error_code(u32 intr_info)
+{
+	const u32 mask = INTR_INFO_VALID_MASK | INTR_INFO_DELIVER_CODE_MASK;
+
+	return (intr_info & mask) == mask;
+}
+
 enum vmcs_field_width {
 	VMCS_FIELD_WIDTH_U16 = 0,
 	VMCS_FIELD_WIDTH_U64 = 1,
-- 
2.26.0

[PATCH 4/7] KVM: x86: Add intr/vectoring info and error code to kvm_exit tracepoint

[Sean Christopherson]

Extend the kvm_exit tracepoint to align it with kvm_nested_vmexit in
terms of what information is captured.  On SVM, this means adding
interrupt info and error code, and on VMX it means adding ITD vectoring
and error code.  This sets the stage for macrofying the kvm_exit
tracepoint definition so that it can be reused for kvm_nested_vmexit
without loss of information (and the nested version is more helpful).

Opportunistically stuff a zero for VM_EXIT_INTR_INFO if the VM-Enter
failed, as the field is guaranteed to be invalid.  Note, it'd be
possible to further filter the interrupt/exception fields based on the
VM-Exit reason, but the helper is intended only for tracepoints, i.e.
an extra VMREAD or two is a non-issue, the failed VM-Enter case is just
low hanging fruit.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/include/asm/kvm_host.h |  7 ++++++-
 arch/x86/kvm/svm/svm.c          |  9 ++++++++-
 arch/x86/kvm/trace.h            | 12 +++++++++---
 arch/x86/kvm/vmx/vmx.c          | 18 ++++++++++++++++--
 4 files changed, 39 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 1bab87a444d78..d8a24252e20e1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1143,7 +1143,12 @@ struct kvm_x86_ops {
 	/* Returns actual tsc_offset set in active VMCS */
 	u64 (*write_l1_tsc_offset)(struct kvm_vcpu *vcpu, u64 offset);
 
-	void (*get_exit_info)(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2);
+	/*
+	 * Retrieve somewhat arbitrary exit information.  Intended to be used
+	 * only from within tracepoints to avoid VMREADs when tracing is off.
+	 */
+	void (*get_exit_info)(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2,
+			      u32 *exit_int_info, u32 *exit_int_info_err_code);
 
 	int (*check_intercept)(struct kvm_vcpu *vcpu,
 			       struct x86_instruction_info *info,
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 1fea39ff33077..8ab3413094500 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2917,12 +2917,19 @@ static void dump_vmcb(struct kvm_vcpu *vcpu)
 	       "excp_to:", save->last_excp_to);
 }
 
-static void svm_get_exit_info(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2)
+static void svm_get_exit_info(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2,
+			      u32 *intr_info, u32 *error_code)
 {
 	struct vmcb_control_area *control = &to_svm(vcpu)->vmcb->control;
 
 	*info1 = control->exit_info_1;
 	*info2 = control->exit_info_2;
+	*intr_info = control->exit_int_info;
+	if ((*intr_info & SVM_EXITINTINFO_VALID) &&
+	    (*intr_info & SVM_EXITINTINFO_VALID_ERR))
+		*error_code = control->exit_int_info_err;
+	else
+		*error_code = 0;
 }
 
 static int handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index 00e567378ae1f..4192b72c72fd8 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -248,6 +248,8 @@ TRACE_EVENT(kvm_exit,
 		__field(	u32,	        isa             )
 		__field(	u64,	        info1           )
 		__field(	u64,	        info2           )
+		__field(	u32,	        intr_info	)
+		__field(	u32,	        error_code	)
 		__field(	unsigned int,	vcpu_id         )
 	),
 
@@ -257,13 +259,17 @@ TRACE_EVENT(kvm_exit,
 		__entry->isa            = isa;
 		__entry->vcpu_id        = vcpu->vcpu_id;
 		kvm_x86_ops.get_exit_info(vcpu, &__entry->info1,
-					   &__entry->info2);
+					  &__entry->info2,
+					  &__entry->intr_info,
+					  &__entry->error_code);
 	),
 
-	TP_printk("vcpu %u reason %s%s%s rip 0x%lx info %llx %llx",
+	TP_printk("vcpu %u reason %s%s%s rip 0x%lx info1 0x%016llx "
+		  "info2 0x%016llx intr_info 0x%08x error_code 0x%08x",
 		  __entry->vcpu_id,
 		  kvm_print_exit_reason(__entry->exit_reason, __entry->isa),
-		  __entry->guest_rip, __entry->info1, __entry->info2)
+		  __entry->guest_rip, __entry->info1, __entry->info2,
+		  __entry->intr_info, __entry->error_code)
 );
 
 /*
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 1bb59ae5016dc..c1448f42a9522 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5751,10 +5751,24 @@ static int (*kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = {
 static const int kvm_vmx_max_exit_handlers =
 	ARRAY_SIZE(kvm_vmx_exit_handlers);
 
-static void vmx_get_exit_info(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2)
+static void vmx_get_exit_info(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2,
+			      u32 *intr_info, u32 *error_code)
 {
+	struct vcpu_vmx *vmx = to_vmx(vcpu);
+
 	*info1 = vmx_get_exit_qual(vcpu);
-	*info2 = vmx_get_intr_info(vcpu);
+	if (!(vmx->exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY)) {
+		*info2 = vmx->idt_vectoring_info;
+		*intr_info = vmx_get_intr_info(vcpu);
+		if (is_exception_with_error_code(*intr_info))
+			*error_code = vmcs_read32(VM_EXIT_INTR_ERROR_CODE);
+		else
+			*error_code = 0;
+	} else {
+		*info2 = 0;
+		*intr_info = 0;
+		*error_code = 0;
+	}
 }
 
 static void vmx_destroy_pml_buffer(struct vcpu_vmx *vmx)
-- 
2.26.0

[PATCH 5/7] KVM: x86: Add macro wrapper for defining kvm_exit tracepoint

[Sean Christopherson]

Macrofy the definition of kvm_exit so that the definition can be reused
verbatim by kvm_nested_vmexit.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/trace.h | 69 +++++++++++++++++++++++---------------------
 1 file changed, 36 insertions(+), 33 deletions(-)

diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index 4192b72c72fd8..6cb75ba494fcd 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -235,42 +235,45 @@ TRACE_EVENT(kvm_apic,
 	(isa == KVM_ISA_VMX) ?						\
 	__print_flags(exit_reason & ~0xffff, " ", VMX_EXIT_REASON_FLAGS) : ""
 
+#define TRACE_EVENT_KVM_EXIT(name)					     \
+TRACE_EVENT(name,							     \
+	TP_PROTO(unsigned int exit_reason, struct kvm_vcpu *vcpu, u32 isa),  \
+	TP_ARGS(exit_reason, vcpu, isa),				     \
+									     \
+	TP_STRUCT__entry(						     \
+		__field(	unsigned int,	exit_reason	)	     \
+		__field(	unsigned long,	guest_rip	)	     \
+		__field(	u32,	        isa             )	     \
+		__field(	u64,	        info1           )	     \
+		__field(	u64,	        info2           )	     \
+		__field(	u32,	        intr_info	)	     \
+		__field(	u32,	        error_code	)	     \
+		__field(	unsigned int,	vcpu_id         )	     \
+	),								     \
+									     \
+	TP_fast_assign(							     \
+		__entry->exit_reason	= exit_reason;			     \
+		__entry->guest_rip	= kvm_rip_read(vcpu);		     \
+		__entry->isa            = isa;				     \
+		__entry->vcpu_id        = vcpu->vcpu_id;		     \
+		kvm_x86_ops.get_exit_info(vcpu, &__entry->info1,	     \
+					  &__entry->info2,		     \
+					  &__entry->intr_info,		     \
+					  &__entry->error_code);	     \
+	),								     \
+									     \
+	TP_printk("vcpu %u reason %s%s%s rip 0x%lx info1 0x%016llx "	     \
+		  "info2 0x%016llx intr_info 0x%08x error_code 0x%08x",	     \
+		  __entry->vcpu_id,					     \
+		  kvm_print_exit_reason(__entry->exit_reason, __entry->isa), \
+		  __entry->guest_rip, __entry->info1, __entry->info2,	     \
+		  __entry->intr_info, __entry->error_code)		     \
+)
+
 /*
  * Tracepoint for kvm guest exit:
  */
-TRACE_EVENT(kvm_exit,
-	TP_PROTO(unsigned int exit_reason, struct kvm_vcpu *vcpu, u32 isa),
-	TP_ARGS(exit_reason, vcpu, isa),
-
-	TP_STRUCT__entry(
-		__field(	unsigned int,	exit_reason	)
-		__field(	unsigned long,	guest_rip	)
-		__field(	u32,	        isa             )
-		__field(	u64,	        info1           )
-		__field(	u64,	        info2           )
-		__field(	u32,	        intr_info	)
-		__field(	u32,	        error_code	)
-		__field(	unsigned int,	vcpu_id         )
-	),
-
-	TP_fast_assign(
-		__entry->exit_reason	= exit_reason;
-		__entry->guest_rip	= kvm_rip_read(vcpu);
-		__entry->isa            = isa;
-		__entry->vcpu_id        = vcpu->vcpu_id;
-		kvm_x86_ops.get_exit_info(vcpu, &__entry->info1,
-					  &__entry->info2,
-					  &__entry->intr_info,
-					  &__entry->error_code);
-	),
-
-	TP_printk("vcpu %u reason %s%s%s rip 0x%lx info1 0x%016llx "
-		  "info2 0x%016llx intr_info 0x%08x error_code 0x%08x",
-		  __entry->vcpu_id,
-		  kvm_print_exit_reason(__entry->exit_reason, __entry->isa),
-		  __entry->guest_rip, __entry->info1, __entry->info2,
-		  __entry->intr_info, __entry->error_code)
-);
+TRACE_EVENT_KVM_EXIT(kvm_exit);
 
 /*
  * Tracepoint for kvm interrupt injection:
-- 
2.26.0

[PATCH 6/7] KVM: x86: Use common definition for kvm_nested_vmexit tracepoint

[Sean Christopherson]

Use the newly introduced TRACE_EVENT_KVM_EXIT to define the guts of
kvm_nested_vmexit so that it captures and prints the same information as
with kvm_exit.  This has the bonus side effect of fixing the interrupt
info and error code printing for the case where they're invalid, e.g. if
the exit was a failed VM-Entry.  This also sets the stage for retrieving
EXIT_QUALIFICATION and VM_EXIT_INTR_INFO in nested_vmx_reflect_vmexit()
if and only if the VM-Exit is being routed to L1.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/svm/svm.c    |  7 +------
 arch/x86/kvm/trace.h      | 34 +---------------------------------
 arch/x86/kvm/vmx/nested.c |  5 +----
 3 files changed, 3 insertions(+), 43 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 8ab3413094500..133581c5b0dc0 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2950,12 +2950,7 @@ static int handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
 	if (is_guest_mode(vcpu)) {
 		int vmexit;
 
-		trace_kvm_nested_vmexit(vcpu, exit_code,
-					svm->vmcb->control.exit_info_1,
-					svm->vmcb->control.exit_info_2,
-					svm->vmcb->control.exit_int_info,
-					svm->vmcb->control.exit_int_info_err,
-					KVM_ISA_SVM);
+		trace_kvm_nested_vmexit(exit_code, vcpu, KVM_ISA_SVM);
 
 		vmexit = nested_svm_exit_special(svm);
 
diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index 6cb75ba494fcd..e29576985e03a 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -579,39 +579,7 @@ TRACE_EVENT(kvm_nested_intercepts,
 /*
  * Tracepoint for #VMEXIT while nested
  */
-TRACE_EVENT(kvm_nested_vmexit,
-	    TP_PROTO(struct kvm_vcpu *vcpu, __u32 exit_code,
-		     __u64 exit_info1, __u64 exit_info2,
-		     __u32 exit_int_info, __u32 exit_int_info_err, __u32 isa),
-	    TP_ARGS(vcpu, exit_code, exit_info1, exit_info2,
-		    exit_int_info, exit_int_info_err, isa),
-
-	TP_STRUCT__entry(
-		__field(	__u64,		rip			)
-		__field(	__u32,		exit_code		)
-		__field(	__u64,		exit_info1		)
-		__field(	__u64,		exit_info2		)
-		__field(	__u32,		exit_int_info		)
-		__field(	__u32,		exit_int_info_err	)
-		__field(	__u32,		isa			)
-	),
-
-	TP_fast_assign(
-		__entry->rip			= kvm_rip_read(vcpu);
-		__entry->exit_code		= exit_code;
-		__entry->exit_info1		= exit_info1;
-		__entry->exit_info2		= exit_info2;
-		__entry->exit_int_info		= exit_int_info;
-		__entry->exit_int_info_err	= exit_int_info_err;
-		__entry->isa			= isa;
-	),
-	TP_printk("rip: 0x%016llx reason: %s%s%s ext_inf1: 0x%016llx "
-		  "ext_inf2: 0x%016llx ext_int: 0x%08x ext_int_err: 0x%08x",
-		  __entry->rip,
-		  kvm_print_exit_reason(__entry->exit_code, __entry->isa),
-		  __entry->exit_info1, __entry->exit_info2,
-		  __entry->exit_int_info, __entry->exit_int_info_err)
-);
+TRACE_EVENT_KVM_EXIT(kvm_nested_vmexit);
 
 /*
  * Tracepoint for #VMEXIT reinjected to the guest
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index fc70644b916ca..f437d99f4db09 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -5912,10 +5912,7 @@ bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu)
 	exit_intr_info = vmx_get_intr_info(vcpu);
 	exit_qual = vmx_get_exit_qual(vcpu);
 
-	trace_kvm_nested_vmexit(vcpu, exit_reason, exit_qual,
-				vmx->idt_vectoring_info, exit_intr_info,
-				vmcs_read32(VM_EXIT_INTR_ERROR_CODE),
-				KVM_ISA_VMX);
+	trace_kvm_nested_vmexit(exit_reason, vcpu, KVM_ISA_VMX);
 
 	/* If L0 (KVM) wants the exit, it trumps L1's desires. */
 	if (nested_vmx_l0_wants_exit(vcpu, exit_reason))
-- 
2.26.0

[PATCH 7/7] KVM: nVMX: Read EXIT_QUAL and INTR_INFO only when needed for nested exit

[Sean Christopherson]

Read vmcs.EXIT_QUALIFICATION and vmcs.VM_EXIT_INTR_INFO only when the
VM-Exit is being reflected to L1 now that they are no longer passed
directly to the kvm_nested_vmexit tracepoint.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/vmx/nested.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index f437d99f4db09..cc5f0085989c7 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -5909,9 +5909,6 @@ bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu)
 		goto reflect_vmexit;
 	}
 
-	exit_intr_info = vmx_get_intr_info(vcpu);
-	exit_qual = vmx_get_exit_qual(vcpu);
-
 	trace_kvm_nested_vmexit(exit_reason, vcpu, KVM_ISA_VMX);
 
 	/* If L0 (KVM) wants the exit, it trumps L1's desires. */
@@ -5928,12 +5925,14 @@ bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu)
 	 * need to be synthesized by querying the in-kernel LAPIC, but external
 	 * interrupts are never reflected to L1 so it's a non-issue.
 	 */
+	exit_intr_info = vmx_get_intr_info(vcpu);
 	if (is_exception_with_error_code(exit_intr_info)) {
 		struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
 
 		vmcs12->vm_exit_intr_error_code =
 			vmcs_read32(VM_EXIT_INTR_ERROR_CODE);
 	}
+	exit_qual = vmx_get_exit_qual(vcpu);
 
 reflect_vmexit:
 	nested_vmx_vmexit(vcpu, exit_reason, exit_intr_info, exit_qual);
-- 
2.26.0

Re: [PATCH 6/7] KVM: x86: Use common definition for kvm_nested_vmexit tracepoint

[Vitaly Kuznetsov]

Sean Christopherson <sean.j.christopherson@intel.com> writes:

> Use the newly introduced TRACE_EVENT_KVM_EXIT to define the guts of
> kvm_nested_vmexit so that it captures and prints the same information as
> with kvm_exit.  This has the bonus side effect of fixing the interrupt
> info and error code printing for the case where they're invalid, e.g. if
> the exit was a failed VM-Entry.  This also sets the stage for retrieving
> EXIT_QUALIFICATION and VM_EXIT_INTR_INFO in nested_vmx_reflect_vmexit()
> if and only if the VM-Exit is being routed to L1.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
>  arch/x86/kvm/svm/svm.c    |  7 +------
>  arch/x86/kvm/trace.h      | 34 +---------------------------------
>  arch/x86/kvm/vmx/nested.c |  5 +----
>  3 files changed, 3 insertions(+), 43 deletions(-)
>
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index 8ab3413094500..133581c5b0dc0 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -2950,12 +2950,7 @@ static int handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
>  	if (is_guest_mode(vcpu)) {
>  		int vmexit;
>  
> -		trace_kvm_nested_vmexit(vcpu, exit_code,
> -					svm->vmcb->control.exit_info_1,
> -					svm->vmcb->control.exit_info_2,
> -					svm->vmcb->control.exit_int_info,
> -					svm->vmcb->control.exit_int_info_err,
> -					KVM_ISA_SVM);
> +		trace_kvm_nested_vmexit(exit_code, vcpu, KVM_ISA_SVM);
>  
>  		vmexit = nested_svm_exit_special(svm);
>  
> diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
> index 6cb75ba494fcd..e29576985e03a 100644
> --- a/arch/x86/kvm/trace.h
> +++ b/arch/x86/kvm/trace.h
> @@ -579,39 +579,7 @@ TRACE_EVENT(kvm_nested_intercepts,
>  /*
>   * Tracepoint for #VMEXIT while nested
>   */
> -TRACE_EVENT(kvm_nested_vmexit,
> -	    TP_PROTO(struct kvm_vcpu *vcpu, __u32 exit_code,
> -		     __u64 exit_info1, __u64 exit_info2,
> -		     __u32 exit_int_info, __u32 exit_int_info_err, __u32 isa),
> -	    TP_ARGS(vcpu, exit_code, exit_info1, exit_info2,
> -		    exit_int_info, exit_int_info_err, isa),
> -
> -	TP_STRUCT__entry(
> -		__field(	__u64,		rip			)
> -		__field(	__u32,		exit_code		)
> -		__field(	__u64,		exit_info1		)
> -		__field(	__u64,		exit_info2		)
> -		__field(	__u32,		exit_int_info		)
> -		__field(	__u32,		exit_int_info_err	)
> -		__field(	__u32,		isa			)
> -	),
> -
> -	TP_fast_assign(
> -		__entry->rip			= kvm_rip_read(vcpu);
> -		__entry->exit_code		= exit_code;
> -		__entry->exit_info1		= exit_info1;
> -		__entry->exit_info2		= exit_info2;
> -		__entry->exit_int_info		= exit_int_info;
> -		__entry->exit_int_info_err	= exit_int_info_err;
> -		__entry->isa			= isa;
> -	),
> -	TP_printk("rip: 0x%016llx reason: %s%s%s ext_inf1: 0x%016llx "
> -		  "ext_inf2: 0x%016llx ext_int: 0x%08x ext_int_err: 0x%08x",
> -		  __entry->rip,
> -		  kvm_print_exit_reason(__entry->exit_code, __entry->isa),
> -		  __entry->exit_info1, __entry->exit_info2,
> -		  __entry->exit_int_info, __entry->exit_int_info_err)
> -);
> +TRACE_EVENT_KVM_EXIT(kvm_nested_vmexit);
>  
>  /*
>   * Tracepoint for #VMEXIT reinjected to the guest
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index fc70644b916ca..f437d99f4db09 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -5912,10 +5912,7 @@ bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu)
>  	exit_intr_info = vmx_get_intr_info(vcpu);
>  	exit_qual = vmx_get_exit_qual(vcpu);
>  
> -	trace_kvm_nested_vmexit(vcpu, exit_reason, exit_qual,
> -				vmx->idt_vectoring_info, exit_intr_info,
> -				vmcs_read32(VM_EXIT_INTR_ERROR_CODE),
> -				KVM_ISA_VMX);
> +	trace_kvm_nested_vmexit(exit_reason, vcpu, KVM_ISA_VMX);
>  
>  	/* If L0 (KVM) wants the exit, it trumps L1's desires. */
>  	if (nested_vmx_l0_wants_exit(vcpu, exit_reason))

With so many lines removed I'm almost in love with the patch! However,
when testing on SVM (unrelated?) my trace log looks a bit ugly:

           <...>-315119 [010]  3733.092646: kvm_nested_vmexit:    CAN'T FIND FIELD "rip"<CANT FIND FIELD exit_code>vcpu 0 reason npf rip 0x400433 info1 0x0000000200000006 info2 0x0000000000641000 intr_info 0x00000000 error_code 0x00000000
           <...>-315119 [010]  3733.092655: kvm_nested_vmexit:    CAN'T FIND FIELD "rip"<CANT FIND FIELD exit_code>vcpu 0 reason npf rip 0x400433 info1 0x0000000100000014 info2 0x0000000000400000 intr_info 0x00000000 error_code 0x00000000

...

but after staring at this for some time I still don't see where this
comes from :-( ... but reverting this commit helps:

 qemu-system-x86-9928  [022]   379.260656: kvm_nested_vmexit:    rip 400433 reason EXIT_NPF info1 200000006 info2 641000 int_info 0 int_info_err 0
 qemu-system-x86-9928  [022]   379.260666: kvm_nested_vmexit:    rip 400433 reason EXIT_NPF info1 100000014 info2 400000 int_info 0 int_info_err 0

-- 
Vitaly

Re: [PATCH 6/7] KVM: x86: Use common definition for kvm_nested_vmexit tracepoint

[Sean Christopherson]

On Mon, Jul 20, 2020 at 06:52:15PM +0200, Vitaly Kuznetsov wrote:
> Sean Christopherson <sean.j.christopherson@intel.com> writes:
> > +TRACE_EVENT_KVM_EXIT(kvm_nested_vmexit);
> >  
> >  /*
> >   * Tracepoint for #VMEXIT reinjected to the guest
> > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> > index fc70644b916ca..f437d99f4db09 100644
> > --- a/arch/x86/kvm/vmx/nested.c
> > +++ b/arch/x86/kvm/vmx/nested.c
> > @@ -5912,10 +5912,7 @@ bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu)
> >  	exit_intr_info = vmx_get_intr_info(vcpu);
> >  	exit_qual = vmx_get_exit_qual(vcpu);
> >  
> > -	trace_kvm_nested_vmexit(vcpu, exit_reason, exit_qual,
> > -				vmx->idt_vectoring_info, exit_intr_info,
> > -				vmcs_read32(VM_EXIT_INTR_ERROR_CODE),
> > -				KVM_ISA_VMX);
> > +	trace_kvm_nested_vmexit(exit_reason, vcpu, KVM_ISA_VMX);
> >  
> >  	/* If L0 (KVM) wants the exit, it trumps L1's desires. */
> >  	if (nested_vmx_l0_wants_exit(vcpu, exit_reason))
> 
> With so many lines removed I'm almost in love with the patch! However,
> when testing on SVM (unrelated?) my trace log looks a bit ugly:
> 
>            <...>-315119 [010]  3733.092646: kvm_nested_vmexit:    CAN'T FIND FIELD "rip"<CANT FIND FIELD exit_code>vcpu 0 reason npf rip 0x400433 info1 0x0000000200000006 info2 0x0000000000641000 intr_info 0x00000000 error_code 0x00000000
>            <...>-315119 [010]  3733.092655: kvm_nested_vmexit:    CAN'T FIND FIELD "rip"<CANT FIND FIELD exit_code>vcpu 0 reason npf rip 0x400433 info1 0x0000000100000014 info2 0x0000000000400000 intr_info 0x00000000 error_code 0x00000000
> 
> ...
> 
> but after staring at this for some time I still don't see where this
> comes from :-( ... but reverting this commit helps:

The CAN'T FIND FIELD blurb comes from tools/lib/traceevent/event-parse.c.

I assume you are using tooling of some form to generate the trace, i.e. the
issue doesn't show up in /sys/kernel/debug/tracing/trace.  If that's the
case, this is more or less ABI breakage :-(
 
>  qemu-system-x86-9928  [022]   379.260656: kvm_nested_vmexit:    rip 400433 reason EXIT_NPF info1 200000006 info2 641000 int_info 0 int_info_err 0
>  qemu-system-x86-9928  [022]   379.260666: kvm_nested_vmexit:    rip 400433 reason EXIT_NPF info1 100000014 info2 400000 int_info 0 int_info_err 0
> 
> -- 
> Vitaly
> 

Re: [PATCH 6/7] KVM: x86: Use common definition for kvm_nested_vmexit tracepoint

[Vitaly Kuznetsov]

Sean Christopherson <sean.j.christopherson@intel.com> writes:

> On Mon, Jul 20, 2020 at 06:52:15PM +0200, Vitaly Kuznetsov wrote:
>> Sean Christopherson <sean.j.christopherson@intel.com> writes:
>> > +TRACE_EVENT_KVM_EXIT(kvm_nested_vmexit);
>> >  
>> >  /*
>> >   * Tracepoint for #VMEXIT reinjected to the guest
>> > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
>> > index fc70644b916ca..f437d99f4db09 100644
>> > --- a/arch/x86/kvm/vmx/nested.c
>> > +++ b/arch/x86/kvm/vmx/nested.c
>> > @@ -5912,10 +5912,7 @@ bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu)
>> >  	exit_intr_info = vmx_get_intr_info(vcpu);
>> >  	exit_qual = vmx_get_exit_qual(vcpu);
>> >  
>> > -	trace_kvm_nested_vmexit(vcpu, exit_reason, exit_qual,
>> > -				vmx->idt_vectoring_info, exit_intr_info,
>> > -				vmcs_read32(VM_EXIT_INTR_ERROR_CODE),
>> > -				KVM_ISA_VMX);
>> > +	trace_kvm_nested_vmexit(exit_reason, vcpu, KVM_ISA_VMX);
>> >  
>> >  	/* If L0 (KVM) wants the exit, it trumps L1's desires. */
>> >  	if (nested_vmx_l0_wants_exit(vcpu, exit_reason))
>> 
>> With so many lines removed I'm almost in love with the patch! However,
>> when testing on SVM (unrelated?) my trace log looks a bit ugly:
>> 
>>            <...>-315119 [010]  3733.092646: kvm_nested_vmexit:    CAN'T FIND FIELD "rip"<CANT FIND FIELD exit_code>vcpu 0 reason npf rip 0x400433 info1 0x0000000200000006 info2 0x0000000000641000 intr_info 0x00000000 error_code 0x00000000
>>            <...>-315119 [010]  3733.092655: kvm_nested_vmexit:    CAN'T FIND FIELD "rip"<CANT FIND FIELD exit_code>vcpu 0 reason npf rip 0x400433 info1 0x0000000100000014 info2 0x0000000000400000 intr_info 0x00000000 error_code 0x00000000
>> 
>> ...
>> 
>> but after staring at this for some time I still don't see where this
>> comes from :-( ... but reverting this commit helps:
>
> The CAN'T FIND FIELD blurb comes from tools/lib/traceevent/event-parse.c.
>
> I assume you are using tooling of some form to generate the trace, i.e. the
> issue doesn't show up in /sys/kernel/debug/tracing/trace.  If that's the
> case, this is more or less ABI breakage :-(
>  

Right you are,

the tool is called 'trace-cmd record -e kvm ...' / 'trace-cmd report'
but I always thought it's not any different from looking at
/sys/kernel/debug/tracing/trace directly. Apparently I was wrong. 'cat
/sys/kernel/debug/tracing/trace' seems to be OK, e.g.:

 qemu-system-x86-20263 [006] .... 75982.292657: kvm_nested_vmexit: vcpu 0 reason hypercall rip 0x40122f info1 0x0000000000000000 info2 0x0000000000000000 intr_info 0x00000000 error_code 0x00000000

-- 
Vitaly

Re: [PATCH 6/7] KVM: x86: Use common definition for kvm_nested_vmexit tracepoint

[Sean Christopherson]

+Steve

Background: KVM has two tracepoints that effectively trace the same thing
(VM-Exit vs. nested VM-Exit), but use completely different formatting and
nomenclature for each of the existing tracepoints.  I want to add a common
macro to create the tracepoints so that they capture the exact same info
and report it with the exact same format.  But that means breaking the
"ABI" for one of the tracepoints, e.g. trace-cmd barfs on the rename of
exit_code to exit_reason.

Was there ever a verdict on whether or not tracepoints are considered ABI
and thus must retain backwards compatibility?

If not, what's the proper way to upstream changes to trace-cmd?

Thanks!

On Tue, Jul 21, 2020 at 03:59:06PM +0200, Vitaly Kuznetsov wrote:
> Sean Christopherson <sean.j.christopherson@intel.com> writes:
> >> Sean Christopherson <sean.j.christopherson@intel.com> writes:
> >> With so many lines removed I'm almost in love with the patch! However,
> >> when testing on SVM (unrelated?) my trace log looks a bit ugly:
> >> 
> >>            <...>-315119 [010]  3733.092646: kvm_nested_vmexit:    CAN'T FIND FIELD "rip"<CANT FIND FIELD exit_code>vcpu 0 reason npf rip 0x400433 info1 0x0000000200000006 info2 0x0000000000641000 intr_info 0x00000000 error_code 0x00000000
> >>            <...>-315119 [010]  3733.092655: kvm_nested_vmexit:    CAN'T FIND FIELD "rip"<CANT FIND FIELD exit_code>vcpu 0 reason npf rip 0x400433 info1 0x0000000100000014 info2 0x0000000000400000 intr_info 0x00000000 error_code 0x00000000
> >> 
> >> ...
> >> 
> >> but after staring at this for some time I still don't see where this
> >> comes from :-( ... but reverting this commit helps:
> >
> > The CAN'T FIND FIELD blurb comes from tools/lib/traceevent/event-parse.c.
> >
> > I assume you are using tooling of some form to generate the trace, i.e. the
> > issue doesn't show up in /sys/kernel/debug/tracing/trace.  If that's the
> > case, this is more or less ABI breakage :-(
> >  
> 
> Right you are,
> 
> the tool is called 'trace-cmd record -e kvm ...' / 'trace-cmd report'
> but I always thought it's not any different from looking at
> /sys/kernel/debug/tracing/trace directly. Apparently I was wrong. 'cat
> /sys/kernel/debug/tracing/trace' seems to be OK, e.g.:
> 
>  qemu-system-x86-20263 [006] .... 75982.292657: kvm_nested_vmexit: vcpu 0 reason hypercall rip 0x40122f info1 0x0000000000000000 info2 0x0000000000000000 intr_info 0x00000000 error_code 0x00000000
> 
> -- 
> Vitaly
> 

Re: [PATCH 6/7] KVM: x86: Use common definition for kvm_nested_vmexit tracepoint

[Steven Rostedt]

On Tue, 21 Jul 2020 12:31:30 -0700
Sean Christopherson <sean.j.christopherson@intel.com> wrote:

> +Steve
> 
> Background: KVM has two tracepoints that effectively trace the same thing
> (VM-Exit vs. nested VM-Exit), but use completely different formatting and
> nomenclature for each of the existing tracepoints.  I want to add a common
> macro to create the tracepoints so that they capture the exact same info
> and report it with the exact same format.  But that means breaking the
> "ABI" for one of the tracepoints, e.g. trace-cmd barfs on the rename of
> exit_code to exit_reason.

Feel free to update it.

> 
> Was there ever a verdict on whether or not tracepoints are considered ABI
> and thus must retain backwards compatibility?
> 
> If not, what's the proper way to upstream changes to trace-cmd?
> 

There's a kvm plugin in the libtraceevent code.

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/lib/traceevent/plugins/plugin_kvm.c

This overrides how the events are read. In the callback handler
(e.g. kvm_nested_vmexit_handle()), you can test if "rip" is there or
not. If it is not, you can do something different. For example:

	struct tep_format_field *field;

	field = tep_find_any_field(event, "rip");
	if (field) {
		tep_print_num_field(s, "rip %llx ", event, "rip", record, 1)
		[..]
	} else {
		/* do something new */
	}

You can test if fields exist and have the plugins do different things
depending on the format of an event. This is what I do in case an event
changes in the future.

-- Steve

Re: [PATCH 6/7] KVM: x86: Use common definition for kvm_nested_vmexit tracepoint

[Sean Christopherson]

On Tue, Jul 21, 2020 at 03:59:06PM +0200, Vitaly Kuznetsov wrote:
> Sean Christopherson <sean.j.christopherson@intel.com> writes:
> 
> > On Mon, Jul 20, 2020 at 06:52:15PM +0200, Vitaly Kuznetsov wrote:
> >> Sean Christopherson <sean.j.christopherson@intel.com> writes:
> >> > +TRACE_EVENT_KVM_EXIT(kvm_nested_vmexit);
> >> >  
> >> >  /*
> >> >   * Tracepoint for #VMEXIT reinjected to the guest
> >> > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> >> > index fc70644b916ca..f437d99f4db09 100644
> >> > --- a/arch/x86/kvm/vmx/nested.c
> >> > +++ b/arch/x86/kvm/vmx/nested.c
> >> > @@ -5912,10 +5912,7 @@ bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu)
> >> >  	exit_intr_info = vmx_get_intr_info(vcpu);
> >> >  	exit_qual = vmx_get_exit_qual(vcpu);
> >> >  
> >> > -	trace_kvm_nested_vmexit(vcpu, exit_reason, exit_qual,
> >> > -				vmx->idt_vectoring_info, exit_intr_info,
> >> > -				vmcs_read32(VM_EXIT_INTR_ERROR_CODE),
> >> > -				KVM_ISA_VMX);
> >> > +	trace_kvm_nested_vmexit(exit_reason, vcpu, KVM_ISA_VMX);
> >> >  
> >> >  	/* If L0 (KVM) wants the exit, it trumps L1's desires. */
> >> >  	if (nested_vmx_l0_wants_exit(vcpu, exit_reason))
> >> 
> >> With so many lines removed I'm almost in love with the patch! However,
> >> when testing on SVM (unrelated?) my trace log looks a bit ugly:
> >> 
> >>            <...>-315119 [010]  3733.092646: kvm_nested_vmexit:    CAN'T FIND FIELD "rip"<CANT FIND FIELD exit_code>vcpu 0 reason npf rip 0x400433 info1 0x0000000200000006 info2 0x0000000000641000 intr_info 0x00000000 error_code 0x00000000
> >>            <...>-315119 [010]  3733.092655: kvm_nested_vmexit:    CAN'T FIND FIELD "rip"<CANT FIND FIELD exit_code>vcpu 0 reason npf rip 0x400433 info1 0x0000000100000014 info2 0x0000000000400000 intr_info 0x00000000 error_code 0x00000000
> >> 
> >> ...
> >> 
> >> but after staring at this for some time I still don't see where this
> >> comes from :-( ... but reverting this commit helps:
> >
> > The CAN'T FIND FIELD blurb comes from tools/lib/traceevent/event-parse.c.
> >
> > I assume you are using tooling of some form to generate the trace, i.e. the
> > issue doesn't show up in /sys/kernel/debug/tracing/trace.  If that's the
> > case, this is more or less ABI breakage :-(
> >  
> 
> Right you are,
> 
> the tool is called 'trace-cmd record -e kvm ...' / 'trace-cmd report'

Paolo, any thoughts on how to proceed with this series?  E.g. merge KVM
first and fix trace-cmd second?  Something else?