linux/arch/mips/kvm/trace.h
James Hogan b3cffac04e KVM: MIPS: Fix trace event to save PC directly
Currently the guest exit trace event saves the VCPU pointer to the
structure, and the guest PC is retrieved by dereferencing it when the
event is printed rather than directly from the trace record. This isn't
safe as the printing may occur long afterwards, after the PC has changed
and potentially after the VCPU has been freed. Usually this results in
the same (wrong) PC being printed for multiple trace events. It also
isn't portable as userland has no way to access the VCPU data structure
when interpreting the trace record itself.

Lets save the actual PC in the structure so that the correct value is
accessible later.

Fixes: 669e846e6c ("KVM/MIPS32: MIPS arch specific APIs for KVM")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: <stable@vger.kernel.org> # v3.10+
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2015-03-02 19:17:52 -03:00

45 lines
1.1 KiB
C

/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved.
* Authors: Sanjay Lal <sanjayl@kymasys.com>
*/
#if !defined(_TRACE_KVM_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_KVM_H
#include <linux/tracepoint.h>
#undef TRACE_SYSTEM
#define TRACE_SYSTEM kvm
#define TRACE_INCLUDE_PATH .
#define TRACE_INCLUDE_FILE trace
/* Tracepoints for VM eists */
extern char *kvm_mips_exit_types_str[MAX_KVM_MIPS_EXIT_TYPES];
TRACE_EVENT(kvm_exit,
TP_PROTO(struct kvm_vcpu *vcpu, unsigned int reason),
TP_ARGS(vcpu, reason),
TP_STRUCT__entry(
__field(unsigned long, pc)
__field(unsigned int, reason)
),
TP_fast_assign(
__entry->pc = vcpu->arch.pc;
__entry->reason = reason;
),
TP_printk("[%s]PC: 0x%08lx",
kvm_mips_exit_types_str[__entry->reason],
__entry->pc)
);
#endif /* _TRACE_KVM_H */
/* This part must be outside protection */
#include <trace/define_trace.h>