Commit e7adda28 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: x86: Add requested index to the CPUID tracepoint 



Output the requested index when tracing CPUID emulation; it's basically
mandatory for leafs where the index is meaningful, and is helpful for
verifying KVM correctness even when the index isn't meaningful, e.g. the
trace for a Linux guest's hypervisor_cpuid_base() probing appears to
be broken (returns all zeroes) at first glance, but is correct because
the index is non-zero, i.e. the output values correspond to a random
index in the maximum basic leaf.

Suggested-by: default avatarXiaoyao Li <xiaoyao.li@intel.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent d55c9d40

arch/x86/kvm/cpuid.c

+1 −1
Original line number Diff line number Diff line
@@ -1026,7 +1026,7 @@ bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, 
			}

		}

	}

	trace_kvm_cpuid(orig_function, *eax, *ebx, *ecx, *edx, exact);

	trace_kvm_cpuid(orig_function, index, *eax, *ebx, *ecx, *edx, exact);

	return exact;

}

EXPORT_SYMBOL_GPL(kvm_cpuid);

arch/x86/kvm/trace.h

+8 −5
Original line number Diff line number Diff line
@@ -151,12 +151,14 @@ TRACE_EVENT(kvm_fast_mmio, 
 * Tracepoint for cpuid.

 */

TRACE_EVENT(kvm_cpuid,

	TP_PROTO(unsigned int function, unsigned long rax, unsigned long rbx,

		 unsigned long rcx, unsigned long rdx, bool found),

	TP_ARGS(function, rax, rbx, rcx, rdx, found),

	TP_PROTO(unsigned int function, unsigned int index, unsigned long rax,

		 unsigned long rbx, unsigned long rcx, unsigned long rdx,

		 bool found),

	TP_ARGS(function, index, rax, rbx, rcx, rdx, found),



	TP_STRUCT__entry(

		__field(	unsigned int,	function	)

		__field(	unsigned int,	index		)

		__field(	unsigned long,	rax		)

		__field(	unsigned long,	rbx		)

		__field(	unsigned long,	rcx		)
@@ -166,6 +168,7 @@ TRACE_EVENT(kvm_cpuid, 


	TP_fast_assign(

		__entry->function	= function;

		__entry->index		= index;

		__entry->rax		= rax;

		__entry->rbx		= rbx;

		__entry->rcx		= rcx;
@@ -173,8 +176,8 @@ TRACE_EVENT(kvm_cpuid, 
		__entry->found		= found;

	),



	TP_printk("func %x rax %lx rbx %lx rcx %lx rdx %lx, cpuid entry %s",

		  __entry->function, __entry->rax,

	TP_printk("func %x idx %x rax %lx rbx %lx rcx %lx rdx %lx, cpuid entry %s",

		  __entry->function, __entry->index, __entry->rax,

		  __entry->rbx, __entry->rcx, __entry->rdx,

		  __entry->found ? "found" : "not found")

);

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