On Thu, Jan 08, 2015 at 01:33:35PM -0600, Wei Huang wrote:
> On 01/07/2015 02:27 PM, Wei Huang wrote:
> > arm64 uses its own copy of exit handler (arm64/kvm/handle_exit.c).
> > Currently this file doesn't hook up with any trace points. As a result
> > users might not see certain events (e.g. HVC & WFI) while using ftrace
> > with arm64 KVM. This patch fixes this issue by adding a new trace file
> > for arm64 and linking new trace points with related functions.
> >
> > Signed-off-by: Wei Huang <wei@xxxxxxxxxx>
> > ---
> > arch/arm64/include/asm/kvm_arm.h | 2 ++
> > arch/arm64/include/asm/kvm_emulate.h | 5 ++++
> > arch/arm64/kvm/handle_exit.c | 8 ++++++
> > arch/arm64/kvm/trace.h | 52 ++++++++++++++++++++++++++++++++++++
> > 4 files changed, 67 insertions(+)
> > create mode 100644 arch/arm64/kvm/trace.h
> >
> > diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
> > index 7fd3e27..e3e2350 100644
> > --- a/arch/arm64/include/asm/kvm_arm.h
> > +++ b/arch/arm64/include/asm/kvm_arm.h
> > @@ -256,4 +256,6 @@
> >
> > #define ESR_EL2_EC_WFI_ISS_WFE (1 << 0)
> >
> > +#define ESR_EL2_HVC_IMM_MASK ((1UL << 16) - 1)
> > +
> > #endif /* __ARM64_KVM_ARM_H__ */
> > diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
> > index 8127e45..a6fa2d2 100644
> > --- a/arch/arm64/include/asm/kvm_emulate.h
> > +++ b/arch/arm64/include/asm/kvm_emulate.h
> > @@ -126,6 +126,11 @@ static inline phys_addr_t kvm_vcpu_get_fault_ipa(const struct kvm_vcpu *vcpu)
> > return ((phys_addr_t)vcpu->arch.fault.hpfar_el2 & HPFAR_MASK) << 8;
> > }
> >
> > +static inline u32 kvm_vcpu_hvc_get_imm(const struct kvm_vcpu *vcpu)
> > +{
> > + return kvm_vcpu_get_hsr(vcpu) & ESR_EL2_HVC_IMM_MASK;
> > +}
> > +
> > static inline bool kvm_vcpu_dabt_isvalid(const struct kvm_vcpu *vcpu)
> > {
> > return !!(kvm_vcpu_get_hsr(vcpu) & ESR_EL2_ISV);
> > diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> > index 34b8bd0..4fdb907 100644
> > --- a/arch/arm64/kvm/handle_exit.c
> > +++ b/arch/arm64/kvm/handle_exit.c
> > @@ -26,12 +26,18 @@
> > #include <asm/kvm_mmu.h>
> > #include <asm/kvm_psci.h>
> >
> > +#define CREATE_TRACE_POINTS
> > +#include "trace.h"
> > +
> > typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
> >
> > static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
> > {
> > int ret;
> >
> > + trace_kvm_hvc_arm64(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
> > + kvm_vcpu_hvc_get_imm(vcpu));
> > +
> > ret = kvm_psci_call(vcpu);
> > if (ret < 0) {
> > kvm_inject_undefined(vcpu);
> > @@ -61,6 +67,8 @@ static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
> > */
> > static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
> > {
> > + trace_kvm_wfi_arm64(*vcpu_pc(vcpu));
> > +
> > if (kvm_vcpu_get_hsr(vcpu) & ESR_EL2_EC_WFI_ISS_WFE)
> > kvm_vcpu_on_spin(vcpu);
> > else
> > diff --git a/arch/arm64/kvm/trace.h b/arch/arm64/kvm/trace.h
> > new file mode 100644
> > index 0000000..96c7de0
> > --- /dev/null
> > +++ b/arch/arm64/kvm/trace.h
> > @@ -0,0 +1,52 @@
> > +#if !defined(_TRACE_ARM64_KVM_H) || defined(TRACE_HEADER_MULTI_READ)
> > +#define _TRACE_ARM64_KVM_H
> > +
> > +#include <linux/tracepoint.h>
> > +
> > +#undef TRACE_SYSTEM
> > +#define TRACE_SYSTEM kvm
> > +
> > +TRACE_EVENT(kvm_wfi_arm64,
> > + TP_PROTO(unsigned long vcpu_pc),
> > + TP_ARGS(vcpu_pc),
> > +
> > + TP_STRUCT__entry(
> > + __field(unsigned long, vcpu_pc)
> > + ),
> > +
> > + TP_fast_assign(
> > + __entry->vcpu_pc = vcpu_pc;
> > + ),
> > +
> > + TP_printk("guest executed wfxx at: 0x%08lx", __entry->vcpu_pc)
>
> I realized that there is a typo in TP_printk. "guest executed wfxx" is
> supposed to be "guest executed wfi". Sorry. That is a debug string
> accidentally left behind. Please correct it (or I can send another patch
> if requested).
>
it really should all be _wfx, not wfi, and we should identify if it's a
wfi or wfe we're seeing, now when we're at it. (It could be good for
counting stats too).
>
> > +);
> > +
> > +TRACE_EVENT(kvm_hvc_arm64,
> > + TP_PROTO(unsigned long vcpu_pc, unsigned long r0, unsigned long imm),
> > + TP_ARGS(vcpu_pc, r0, imm),
> > +
> > + TP_STRUCT__entry(
> > + __field(unsigned long, vcpu_pc)
> > + __field(unsigned long, r0)
> > + __field(unsigned long, imm)
> > + ),
> > +
> > + TP_fast_assign(
> > + __entry->vcpu_pc = vcpu_pc;
> > + __entry->r0 = r0;
> > + __entry->imm = imm;
> > + ),
> > +
> > + TP_printk("HVC at 0x%08lx (r0: 0x%08lx, imm: 0x%lx)",
> > + __entry->vcpu_pc, __entry->r0, __entry->imm)
> > +);
> > +
> > +#endif /* _TRACE_ARM64_KVM_H */
> > +
> > +#undef TRACE_INCLUDE_PATH
> > +#define TRACE_INCLUDE_PATH .
> > +#undef TRACE_INCLUDE_FILE
> > +#define TRACE_INCLUDE_FILE trace
> > +
> > +/* This part must be outside protection */
> > +#include <trace/define_trace.h>
> >
This looks like it's going to conflict with Mark Rutland's series:
http://www.spinics.net/lists/arm-kernel/msg388934.html
But it should be relatively easy to fixup the conflicts.
-Christoffer
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