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arm/arm64: KVM: Improve kvm_exit tracepoint

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The ARM architecture only saves the exit class to the HSR (ESR_EL2 for
arm64) on synchronous exceptions, not on asynchronous exceptions like an
IRQ.  However, we only report the exception class on kvm_exit, which is
confusing because an IRQ looks like it exited at some PC with the same
reason as the previous exit.  Add a lookup table for the exception index
and prepend the kvm_exit tracepoint text with the exception type to
clarify this situation.

Also resolve the exception class (EC) to a human-friendly text version
so the trace output becomes immediately usable for debugging this code.

Cc: Wei Huang <wei@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
This commit is contained in:
Christoffer Dall 2015-08-30 15:55:22 +02:00
parent 952105ab52
commit b5905dc12e
4 changed files with 44 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
arch/arm/include/asm/kvm_arm.h
View File

@ -218,4 +218,24 @@
#define HSR_DABT_CM (1U << 8)
#define HSR_DABT_EA (1U << 9)
#define kvm_arm_exception_type \
{0, "RESET" }, \
{1, "UNDEFINED" }, \
{2, "SOFTWARE" }, \
{3, "PREF_ABORT" }, \
{4, "DATA_ABORT" }, \
{5, "IRQ" }, \
{6, "FIQ" }, \
{7, "HVC" }
#define HSRECN(x) { HSR_EC_##x, #x }
#define kvm_arm_exception_class \
HSRECN(UNKNOWN), HSRECN(WFI), HSRECN(CP15_32), HSRECN(CP15_64), \
HSRECN(CP14_MR), HSRECN(CP14_LS), HSRECN(CP_0_13), HSRECN(CP10_ID), \
HSRECN(JAZELLE), HSRECN(BXJ), HSRECN(CP14_64), HSRECN(SVC_HYP), \
HSRECN(HVC), HSRECN(SMC), HSRECN(IABT), HSRECN(IABT_HYP), \
HSRECN(DABT), HSRECN(DABT_HYP)
#endif /* __ARM_KVM_ARM_H__ */

2
arch/arm/kvm/arm.c
View File

@ -635,7 +635,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
* guest time.
*/
kvm_guest_exit();
trace_kvm_exit(kvm_vcpu_trap_get_class(vcpu), *vcpu_pc(vcpu));
trace_kvm_exit(ret, kvm_vcpu_trap_get_class(vcpu), *vcpu_pc(vcpu));
/*
* We must sync the timer state before the vgic state so that

10
arch/arm/kvm/trace.h
View File

@ -25,21 +25,25 @@ TRACE_EVENT(kvm_entry,
);
TRACE_EVENT(kvm_exit,
TP_PROTO(unsigned int exit_reason, unsigned long vcpu_pc),
TP_ARGS(exit_reason, vcpu_pc),
TP_PROTO(int idx, unsigned int exit_reason, unsigned long vcpu_pc),
TP_ARGS(idx, exit_reason, vcpu_pc),
TP_STRUCT__entry(
__field( int, idx )
__field( unsigned int, exit_reason )
__field( unsigned long, vcpu_pc )
),
TP_fast_assign(
__entry->idx = idx;
__entry->exit_reason = exit_reason;
__entry->vcpu_pc = vcpu_pc;
),
TP_printk("HSR_EC: 0x%04x, PC: 0x%08lx",
TP_printk("%s: HSR_EC: 0x%04x (%s), PC: 0x%08lx",
__print_symbolic(__entry->idx, kvm_arm_exception_type),
__entry->exit_reason,
__print_symbolic(__entry->exit_reason, kvm_arm_exception_class),
__entry->vcpu_pc)
);

16
arch/arm64/include/asm/kvm_arm.h
View File

@ -200,4 +200,20 @@
/* Hyp Prefetch Fault Address Register (HPFAR/HDFAR) */
#define HPFAR_MASK (~UL(0xf))
#define kvm_arm_exception_type \
{0, "IRQ" }, \
{1, "TRAP" }
#define ECN(x) { ESR_ELx_EC_##x, #x }
#define kvm_arm_exception_class \
ECN(UNKNOWN), ECN(WFx), ECN(CP15_32), ECN(CP15_64), ECN(CP14_MR), \
ECN(CP14_LS), ECN(FP_ASIMD), ECN(CP10_ID), ECN(CP14_64), ECN(SVC64), \
ECN(HVC64), ECN(SMC64), ECN(SYS64), ECN(IMP_DEF), ECN(IABT_LOW), \
ECN(IABT_CUR), ECN(PC_ALIGN), ECN(DABT_LOW), ECN(DABT_CUR), \
ECN(SP_ALIGN), ECN(FP_EXC32), ECN(FP_EXC64), ECN(SERROR), \
ECN(BREAKPT_LOW), ECN(BREAKPT_CUR), ECN(SOFTSTP_LOW), \
ECN(SOFTSTP_CUR), ECN(WATCHPT_LOW), ECN(WATCHPT_CUR), \
ECN(BKPT32), ECN(VECTOR32), ECN(BRK64)
#endif /* __ARM64_KVM_ARM_H__ */