| Message ID | 1427814488-28467-11-git-send-email-alex.bennee@linaro.org |
|---|---|
| State | New |
| Headers | show |
Andrew Jones <drjones@redhat.com> writes: > $SUBJECT | sed s/guest_debug debug/guest debug/ ? > > On Tue, Mar 31, 2015 at 04:08:08PM +0100, Alex Bennée wrote: >> This includes trace points for: >> kvm_arch_setup_guest_debug >> kvm_arch_clear_guest_debug >> kvm_handle_guest_debug >> >> I've also added some generic register setting trace events so I can >> watch the register values being built up over time. The local >> dump_dbg_regs() function dumps all the HW BKPT and WPT registers. >> >> I've also added a #define trace_dreg to shorten some lines. >> >> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> >> >> diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c >> index 638c111..7c96288 100644 >> --- a/arch/arm64/kvm/debug.c >> +++ b/arch/arm64/kvm/debug.c >> @@ -25,12 +25,37 @@ >> #include <asm/kvm_host.h> >> #include <asm/kvm_emulate.h> >> >> +#include "trace.h" >> + >> +#define trace_dreg(name, value) trace_kvm_arch_setup_debug_reg32(name, value) > > I don't think this name shortener should be necessary Yeah it was just a quick hack as lower down the trace_ statements kept wrapping and it looked ugly. I guess it would be less of an issue if I shorten the setup/clear names. > >> + >> /* These are the bits of MDSCR_EL1 we may mess with */ >> #define MDSCR_EL1_DEBUG_BITS (DBG_MDSCR_SS | \ >> DBG_MDSCR_KDE | \ >> DBG_MDSCR_MDE) >> >> /** >> + * dump_dbg_regs - simple debug helper >> + * >> + * This provides a simple helper to dump the HW debug registers >> + */ >> +static void dump_dbg_regs(struct kvm_vcpu *vcpu, int nb, int nw) >> +{ >> + int i; >> + >> + for (i = 0; i < nb; i++) { >> + trace_printk("bkpt%d: 0x%08x:0x%llx\n", i, >> + (u32) vcpu_sys_reg(vcpu, DBGBCR0_EL1 + i), >> + vcpu_sys_reg(vcpu, DBGBVR0_EL1 + i)); >> + } >> + for (i = 0; i < nb; i++) { >> + trace_printk("wtpt%d: 0x%08x:0x%llx\n", i, >> + (u32) vcpu_sys_reg(vcpu, DBGWCR0_EL1 + i), >> + vcpu_sys_reg(vcpu, DBGWVR0_EL1 + i)); >> + } >> +} >> + >> +/** >> * kvm_arch_setup_debug - set-up debug related stuff >> * >> * @vcpu: the vcpu pointer >> @@ -52,9 +77,13 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) >> { >> bool trap_debug = false; >> >> + trace_kvm_arch_setup_debug(vcpu->guest_debug); >> + >> vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM | MDCR_EL2_TPMCR); >> vcpu->arch.mdcr_el2 |= (MDCR_EL2_TDRA | MDCR_EL2_TDOSA); >> >> + trace_kvm_arch_setup_debug_reg32("MDCR_EL2", vcpu->arch.mdcr_el2); > > Not using your trace_dreg here? I guess you didn't think it was > necessary either. > >> + >> /* >> * If we are not treating debug registers are dirty we need >> * to trap if the guest starts accessing them. >> @@ -66,6 +95,8 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) >> if (vcpu->guest_debug) { >> vcpu->arch.mdcr_el2 |= MDCR_EL2_TDE; >> >> + trace_dreg("MDCR_EL2", vcpu->arch.mdcr_el2); >> + >> /* Save pstate/mdscr */ >> vcpu_debug_saved_reg(vcpu, pstate_ss_bit) = >> *vcpu_cpsr(vcpu) & DBG_SPSR_SS; >> @@ -73,6 +104,11 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) >> vcpu_debug_saved_reg(vcpu, mdscr_el1) = >> vcpu_sys_reg(vcpu, MDSCR_EL1); >> >> + trace_dreg("Save: PSTATE.SS", >> + vcpu_debug_saved_reg(vcpu, pstate_ss_bit)); >> + trace_dreg("Save: MDSCR", >> + vcpu_debug_saved_reg(vcpu, mdscr_el1)); >> + >> /* >> * Single Step (ARM ARM D2.12.3 The software step state >> * machine) >> @@ -88,6 +124,8 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) >> *vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS; >> vcpu_sys_reg(vcpu, MDSCR_EL1) &= ~DBG_MDSCR_SS; >> } >> + trace_dreg("SPSR_EL2", *vcpu_cpsr(vcpu)); >> + trace_dreg("MDSCR_EL1", vcpu_sys_reg(vcpu, MDSCR_EL1)); >> >> /* >> * HW Break/Watch points >> @@ -136,6 +174,9 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) >> &host->dbg_wvr, >> sizeof(__u64)*nw); >> >> + if (trace_kvm_arch_setup_debug_reg32_enabled()) >> + dump_dbg_regs(vcpu, nb, nw); >> + >> /* Make sure hyp.S copies them in/out */ >> vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY; >> /* Also track guest changes */ >> @@ -147,15 +188,24 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) >> vcpu->arch.mdcr_el2 &= ~MDCR_EL2_TDE; >> } >> >> + trace_kvm_arch_setup_debug_reg32("MDCR_EL2", vcpu->arch.mdcr_el2); >> + trace_kvm_arch_setup_debug_reg32("MDSCR_EL1", >> + vcpu_sys_reg(vcpu, MDSCR_EL1)); >> + >> + >> /* Trap debug register access? */ >> if (trap_debug) >> vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA; >> else >> vcpu->arch.mdcr_el2 &= ~MDCR_EL2_TDA; >> + >> + trace_kvm_arch_setup_debug_reg32("MDCR_EL2", vcpu->arch.mdcr_el2); >> } >> >> void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) >> { >> + trace_kvm_arch_clear_debug(vcpu->guest_debug); >> + >> if (vcpu->guest_debug) { >> /* Restore pstate/mdscr bits we may have messed with */ >> *vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS; >> @@ -164,6 +214,8 @@ void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) >> vcpu_sys_reg(vcpu, MDSCR_EL1) = >> vcpu_debug_saved_reg(vcpu, mdscr_el1); >> >> + trace_dreg("SPSR_EL2", *vcpu_cpsr(vcpu)); >> + trace_dreg("MDSCR_EL1", vcpu_sys_reg(vcpu, MDSCR_EL1)); >> /* >> * If we were using HW debug we need to restore the >> * values the guest had set them up with >> @@ -188,6 +240,10 @@ void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) >> memcpy(&vcpu_sys_reg(vcpu, DBGWVR0_EL1), >> ®s->dbg_wvr, >> sizeof(__u64)*nw); >> + >> + if (trace_kvm_arch_setup_debug_reg32_enabled()) >> + dump_dbg_regs(vcpu, nb, nw); >> + >> } >> } >> } >> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c >> index 460a1aa..c6cc69a 100644 >> --- a/arch/arm64/kvm/handle_exit.c >> +++ b/arch/arm64/kvm/handle_exit.c >> @@ -97,6 +97,8 @@ static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run) >> { >> u32 hsr = kvm_vcpu_get_hsr(vcpu); >> >> + trace_kvm_handle_guest_debug(*vcpu_pc(vcpu), hsr); >> + >> run->exit_reason = KVM_EXIT_DEBUG; >> run->debug.arch.hsr = hsr; >> >> diff --git a/arch/arm64/kvm/trace.h b/arch/arm64/kvm/trace.h >> index 157416e9..dffdb49 100644 >> --- a/arch/arm64/kvm/trace.h >> +++ b/arch/arm64/kvm/trace.h >> @@ -44,6 +44,72 @@ TRACE_EVENT(kvm_hvc_arm64, >> __entry->vcpu_pc, __entry->r0, __entry->imm) >> ); >> >> +TRACE_EVENT(kvm_handle_guest_debug, >> + TP_PROTO(unsigned long vcpu_pc, u32 hsr), >> + TP_ARGS(vcpu_pc, hsr), >> + >> + TP_STRUCT__entry( >> + __field(unsigned long, vcpu_pc) >> + __field(u32, hsr) >> + ), >> + >> + TP_fast_assign( >> + __entry->vcpu_pc = vcpu_pc; >> + __entry->hsr = hsr; >> + ), >> + >> + TP_printk("debug exception at 0x%08lx (HSR: 0x%08x)", >> + __entry->vcpu_pc, __entry->hsr) >> +); >> + >> + >> +TRACE_EVENT(kvm_arch_setup_debug, >> + TP_PROTO(__u32 guest_debug), >> + TP_ARGS(guest_debug), >> + >> + TP_STRUCT__entry( >> + __field(__u32, guest_debug) >> + ), >> + >> + TP_fast_assign( >> + __entry->guest_debug = guest_debug; >> + ), >> + >> + TP_printk("flags: 0x%08x", __entry->guest_debug) >> +); >> + >> +TRACE_EVENT(kvm_arch_clear_debug, >> + TP_PROTO(__u32 guest_debug), >> + TP_ARGS(guest_debug), >> + >> + TP_STRUCT__entry( >> + __field(__u32, guest_debug) >> + ), >> + >> + TP_fast_assign( >> + __entry->guest_debug = guest_debug; >> + ), >> + >> + TP_printk("flags: 0x%08x", __entry->guest_debug) >> +); >> + >> +TRACE_EVENT(kvm_arch_setup_debug_reg32, >> + TP_PROTO(const char *name, __u32 value), >> + TP_ARGS(name, value), >> + >> + TP_STRUCT__entry( >> + __field(const char *, name) >> + __field(__u32, value) >> + ), >> + >> + TP_fast_assign( >> + __entry->name = name; >> + __entry->value = value; >> + ), >> + >> + TP_printk("%s now 0x%08x", __entry->name, __entry->value) >> +); >> + >> #endif /* _TRACE_ARM64_KVM_H */ >> >> #undef TRACE_INCLUDE_PATH >> -- >> 2.3.4 >> > > This looks like it would be super noisy. I'm sure that's nice for > developing/debugging, but can't we reduce the, now debugged, version > down to just one trace point per unique, and interesting, path? If you > have several variables you want to see, then maybe they can all be > on the same line. Sure - I kept the multiple register references for debugging but your right it can be compressed down now it's working. > > Also, I'm not sure about the necessity of the dump_dbg_regs function, > but I think you should be able to embed it in the trace event code > using __print_array Thanks, I'll look at that. > > drew
On Tue, Mar 31, 2015 at 04:08:08PM +0100, Alex Bennée wrote: > This includes trace points for: > kvm_arch_setup_guest_debug > kvm_arch_clear_guest_debug > kvm_handle_guest_debug > > I've also added some generic register setting trace events so I can > watch the register values being built up over time. The local > dump_dbg_regs() function dumps all the HW BKPT and WPT registers. > > I've also added a #define trace_dreg to shorten some lines. > > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > > diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c > index 638c111..7c96288 100644 > --- a/arch/arm64/kvm/debug.c > +++ b/arch/arm64/kvm/debug.c > @@ -25,12 +25,37 @@ > #include <asm/kvm_host.h> > #include <asm/kvm_emulate.h> > > +#include "trace.h" > + > +#define trace_dreg(name, value) trace_kvm_arch_setup_debug_reg32(name, value) > + > /* These are the bits of MDSCR_EL1 we may mess with */ > #define MDSCR_EL1_DEBUG_BITS (DBG_MDSCR_SS | \ > DBG_MDSCR_KDE | \ > DBG_MDSCR_MDE) > > /** > + * dump_dbg_regs - simple debug helper > + * > + * This provides a simple helper to dump the HW debug registers > + */ > +static void dump_dbg_regs(struct kvm_vcpu *vcpu, int nb, int nw) > +{ > + int i; > + > + for (i = 0; i < nb; i++) { > + trace_printk("bkpt%d: 0x%08x:0x%llx\n", i, > + (u32) vcpu_sys_reg(vcpu, DBGBCR0_EL1 + i), > + vcpu_sys_reg(vcpu, DBGBVR0_EL1 + i)); > + } > + for (i = 0; i < nb; i++) { > + trace_printk("wtpt%d: 0x%08x:0x%llx\n", i, > + (u32) vcpu_sys_reg(vcpu, DBGWCR0_EL1 + i), > + vcpu_sys_reg(vcpu, DBGWVR0_EL1 + i)); > + } > +} > + > +/** > * kvm_arch_setup_debug - set-up debug related stuff > * > * @vcpu: the vcpu pointer > @@ -52,9 +77,13 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) > { > bool trap_debug = false; > > + trace_kvm_arch_setup_debug(vcpu->guest_debug); > + > vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM | MDCR_EL2_TPMCR); > vcpu->arch.mdcr_el2 |= (MDCR_EL2_TDRA | MDCR_EL2_TDOSA); > > + trace_kvm_arch_setup_debug_reg32("MDCR_EL2", vcpu->arch.mdcr_el2); > + > /* > * If we are not treating debug registers are dirty we need > * to trap if the guest starts accessing them. > @@ -66,6 +95,8 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) > if (vcpu->guest_debug) { > vcpu->arch.mdcr_el2 |= MDCR_EL2_TDE; > > + trace_dreg("MDCR_EL2", vcpu->arch.mdcr_el2); > + > /* Save pstate/mdscr */ > vcpu_debug_saved_reg(vcpu, pstate_ss_bit) = > *vcpu_cpsr(vcpu) & DBG_SPSR_SS; > @@ -73,6 +104,11 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) > vcpu_debug_saved_reg(vcpu, mdscr_el1) = > vcpu_sys_reg(vcpu, MDSCR_EL1); > > + trace_dreg("Save: PSTATE.SS", > + vcpu_debug_saved_reg(vcpu, pstate_ss_bit)); > + trace_dreg("Save: MDSCR", > + vcpu_debug_saved_reg(vcpu, mdscr_el1)); > + > /* > * Single Step (ARM ARM D2.12.3 The software step state > * machine) > @@ -88,6 +124,8 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) > *vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS; > vcpu_sys_reg(vcpu, MDSCR_EL1) &= ~DBG_MDSCR_SS; > } > + trace_dreg("SPSR_EL2", *vcpu_cpsr(vcpu)); > + trace_dreg("MDSCR_EL1", vcpu_sys_reg(vcpu, MDSCR_EL1)); > > /* > * HW Break/Watch points > @@ -136,6 +174,9 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) > &host->dbg_wvr, > sizeof(__u64)*nw); > > + if (trace_kvm_arch_setup_debug_reg32_enabled()) > + dump_dbg_regs(vcpu, nb, nw); > + > /* Make sure hyp.S copies them in/out */ > vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY; > /* Also track guest changes */ > @@ -147,15 +188,24 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) > vcpu->arch.mdcr_el2 &= ~MDCR_EL2_TDE; > } > > + trace_kvm_arch_setup_debug_reg32("MDCR_EL2", vcpu->arch.mdcr_el2); > + trace_kvm_arch_setup_debug_reg32("MDSCR_EL1", > + vcpu_sys_reg(vcpu, MDSCR_EL1)); > + > + > /* Trap debug register access? */ > if (trap_debug) > vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA; > else > vcpu->arch.mdcr_el2 &= ~MDCR_EL2_TDA; > + > + trace_kvm_arch_setup_debug_reg32("MDCR_EL2", vcpu->arch.mdcr_el2); > } > > void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) > { > + trace_kvm_arch_clear_debug(vcpu->guest_debug); > + > if (vcpu->guest_debug) { > /* Restore pstate/mdscr bits we may have messed with */ > *vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS; > @@ -164,6 +214,8 @@ void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) > vcpu_sys_reg(vcpu, MDSCR_EL1) = > vcpu_debug_saved_reg(vcpu, mdscr_el1); > > + trace_dreg("SPSR_EL2", *vcpu_cpsr(vcpu)); > + trace_dreg("MDSCR_EL1", vcpu_sys_reg(vcpu, MDSCR_EL1)); > /* > * If we were using HW debug we need to restore the > * values the guest had set them up with > @@ -188,6 +240,10 @@ void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) > memcpy(&vcpu_sys_reg(vcpu, DBGWVR0_EL1), > ®s->dbg_wvr, > sizeof(__u64)*nw); > + > + if (trace_kvm_arch_setup_debug_reg32_enabled()) > + dump_dbg_regs(vcpu, nb, nw); > + > } > } > } > diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c > index 460a1aa..c6cc69a 100644 > --- a/arch/arm64/kvm/handle_exit.c > +++ b/arch/arm64/kvm/handle_exit.c > @@ -97,6 +97,8 @@ static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run) > { > u32 hsr = kvm_vcpu_get_hsr(vcpu); > > + trace_kvm_handle_guest_debug(*vcpu_pc(vcpu), hsr); > + > run->exit_reason = KVM_EXIT_DEBUG; > run->debug.arch.hsr = hsr; > > diff --git a/arch/arm64/kvm/trace.h b/arch/arm64/kvm/trace.h > index 157416e9..dffdb49 100644 > --- a/arch/arm64/kvm/trace.h > +++ b/arch/arm64/kvm/trace.h > @@ -44,6 +44,72 @@ TRACE_EVENT(kvm_hvc_arm64, > __entry->vcpu_pc, __entry->r0, __entry->imm) > ); > > +TRACE_EVENT(kvm_handle_guest_debug, > + TP_PROTO(unsigned long vcpu_pc, u32 hsr), > + TP_ARGS(vcpu_pc, hsr), > + > + TP_STRUCT__entry( > + __field(unsigned long, vcpu_pc) > + __field(u32, hsr) > + ), > + > + TP_fast_assign( > + __entry->vcpu_pc = vcpu_pc; > + __entry->hsr = hsr; > + ), > + > + TP_printk("debug exception at 0x%08lx (HSR: 0x%08x)", > + __entry->vcpu_pc, __entry->hsr) > +); > + > + > +TRACE_EVENT(kvm_arch_setup_debug, > + TP_PROTO(__u32 guest_debug), > + TP_ARGS(guest_debug), > + > + TP_STRUCT__entry( > + __field(__u32, guest_debug) > + ), > + > + TP_fast_assign( > + __entry->guest_debug = guest_debug; > + ), > + > + TP_printk("flags: 0x%08x", __entry->guest_debug) > +); > + > +TRACE_EVENT(kvm_arch_clear_debug, > + TP_PROTO(__u32 guest_debug), > + TP_ARGS(guest_debug), > + > + TP_STRUCT__entry( > + __field(__u32, guest_debug) > + ), > + > + TP_fast_assign( > + __entry->guest_debug = guest_debug; > + ), > + > + TP_printk("flags: 0x%08x", __entry->guest_debug) > +); > + > +TRACE_EVENT(kvm_arch_setup_debug_reg32, > + TP_PROTO(const char *name, __u32 value), > + TP_ARGS(name, value), > + > + TP_STRUCT__entry( > + __field(const char *, name) > + __field(__u32, value) > + ), > + > + TP_fast_assign( > + __entry->name = name; > + __entry->value = value; > + ), > + > + TP_printk("%s now 0x%08x", __entry->name, __entry->value) > +); > + > #endif /* _TRACE_ARM64_KVM_H */ > > #undef TRACE_INCLUDE_PATH > -- > 2.3.4 > I would guess that as far as merging any of this upstream keeping the kvm_arch_set_debug() and kvm_handle_guest_debug() are worth keeping, but only if the kvm_arch_set_debug() is only called when the guest is actually being debugged from userspace. Thanks, -Christoffer -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c index 638c111..7c96288 100644 --- a/arch/arm64/kvm/debug.c +++ b/arch/arm64/kvm/debug.c @@ -25,12 +25,37 @@ #include <asm/kvm_host.h> #include <asm/kvm_emulate.h> +#include "trace.h" + +#define trace_dreg(name, value) trace_kvm_arch_setup_debug_reg32(name, value) + /* These are the bits of MDSCR_EL1 we may mess with */ #define MDSCR_EL1_DEBUG_BITS (DBG_MDSCR_SS | \ DBG_MDSCR_KDE | \ DBG_MDSCR_MDE) /** + * dump_dbg_regs - simple debug helper + * + * This provides a simple helper to dump the HW debug registers + */ +static void dump_dbg_regs(struct kvm_vcpu *vcpu, int nb, int nw) +{ + int i; + + for (i = 0; i < nb; i++) { + trace_printk("bkpt%d: 0x%08x:0x%llx\n", i, + (u32) vcpu_sys_reg(vcpu, DBGBCR0_EL1 + i), + vcpu_sys_reg(vcpu, DBGBVR0_EL1 + i)); + } + for (i = 0; i < nb; i++) { + trace_printk("wtpt%d: 0x%08x:0x%llx\n", i, + (u32) vcpu_sys_reg(vcpu, DBGWCR0_EL1 + i), + vcpu_sys_reg(vcpu, DBGWVR0_EL1 + i)); + } +} + +/** * kvm_arch_setup_debug - set-up debug related stuff * * @vcpu: the vcpu pointer @@ -52,9 +77,13 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) { bool trap_debug = false; + trace_kvm_arch_setup_debug(vcpu->guest_debug); + vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM | MDCR_EL2_TPMCR); vcpu->arch.mdcr_el2 |= (MDCR_EL2_TDRA | MDCR_EL2_TDOSA); + trace_kvm_arch_setup_debug_reg32("MDCR_EL2", vcpu->arch.mdcr_el2); + /* * If we are not treating debug registers are dirty we need * to trap if the guest starts accessing them. @@ -66,6 +95,8 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) if (vcpu->guest_debug) { vcpu->arch.mdcr_el2 |= MDCR_EL2_TDE; + trace_dreg("MDCR_EL2", vcpu->arch.mdcr_el2); + /* Save pstate/mdscr */ vcpu_debug_saved_reg(vcpu, pstate_ss_bit) = *vcpu_cpsr(vcpu) & DBG_SPSR_SS; @@ -73,6 +104,11 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) vcpu_debug_saved_reg(vcpu, mdscr_el1) = vcpu_sys_reg(vcpu, MDSCR_EL1); + trace_dreg("Save: PSTATE.SS", + vcpu_debug_saved_reg(vcpu, pstate_ss_bit)); + trace_dreg("Save: MDSCR", + vcpu_debug_saved_reg(vcpu, mdscr_el1)); + /* * Single Step (ARM ARM D2.12.3 The software step state * machine) @@ -88,6 +124,8 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) *vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS; vcpu_sys_reg(vcpu, MDSCR_EL1) &= ~DBG_MDSCR_SS; } + trace_dreg("SPSR_EL2", *vcpu_cpsr(vcpu)); + trace_dreg("MDSCR_EL1", vcpu_sys_reg(vcpu, MDSCR_EL1)); /* * HW Break/Watch points @@ -136,6 +174,9 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) &host->dbg_wvr, sizeof(__u64)*nw); + if (trace_kvm_arch_setup_debug_reg32_enabled()) + dump_dbg_regs(vcpu, nb, nw); + /* Make sure hyp.S copies them in/out */ vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY; /* Also track guest changes */ @@ -147,15 +188,24 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) vcpu->arch.mdcr_el2 &= ~MDCR_EL2_TDE; } + trace_kvm_arch_setup_debug_reg32("MDCR_EL2", vcpu->arch.mdcr_el2); + trace_kvm_arch_setup_debug_reg32("MDSCR_EL1", + vcpu_sys_reg(vcpu, MDSCR_EL1)); + + /* Trap debug register access? */ if (trap_debug) vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA; else vcpu->arch.mdcr_el2 &= ~MDCR_EL2_TDA; + + trace_kvm_arch_setup_debug_reg32("MDCR_EL2", vcpu->arch.mdcr_el2); } void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) { + trace_kvm_arch_clear_debug(vcpu->guest_debug); + if (vcpu->guest_debug) { /* Restore pstate/mdscr bits we may have messed with */ *vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS; @@ -164,6 +214,8 @@ void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) vcpu_sys_reg(vcpu, MDSCR_EL1) = vcpu_debug_saved_reg(vcpu, mdscr_el1); + trace_dreg("SPSR_EL2", *vcpu_cpsr(vcpu)); + trace_dreg("MDSCR_EL1", vcpu_sys_reg(vcpu, MDSCR_EL1)); /* * If we were using HW debug we need to restore the * values the guest had set them up with @@ -188,6 +240,10 @@ void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) memcpy(&vcpu_sys_reg(vcpu, DBGWVR0_EL1), ®s->dbg_wvr, sizeof(__u64)*nw); + + if (trace_kvm_arch_setup_debug_reg32_enabled()) + dump_dbg_regs(vcpu, nb, nw); + } } } diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index 460a1aa..c6cc69a 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -97,6 +97,8 @@ static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run) { u32 hsr = kvm_vcpu_get_hsr(vcpu); + trace_kvm_handle_guest_debug(*vcpu_pc(vcpu), hsr); + run->exit_reason = KVM_EXIT_DEBUG; run->debug.arch.hsr = hsr; diff --git a/arch/arm64/kvm/trace.h b/arch/arm64/kvm/trace.h index 157416e9..dffdb49 100644 --- a/arch/arm64/kvm/trace.h +++ b/arch/arm64/kvm/trace.h @@ -44,6 +44,72 @@ TRACE_EVENT(kvm_hvc_arm64, __entry->vcpu_pc, __entry->r0, __entry->imm) ); +TRACE_EVENT(kvm_handle_guest_debug, + TP_PROTO(unsigned long vcpu_pc, u32 hsr), + TP_ARGS(vcpu_pc, hsr), + + TP_STRUCT__entry( + __field(unsigned long, vcpu_pc) + __field(u32, hsr) + ), + + TP_fast_assign( + __entry->vcpu_pc = vcpu_pc; + __entry->hsr = hsr; + ), + + TP_printk("debug exception at 0x%08lx (HSR: 0x%08x)", + __entry->vcpu_pc, __entry->hsr) +); + + +TRACE_EVENT(kvm_arch_setup_debug, + TP_PROTO(__u32 guest_debug), + TP_ARGS(guest_debug), + + TP_STRUCT__entry( + __field(__u32, guest_debug) + ), + + TP_fast_assign( + __entry->guest_debug = guest_debug; + ), + + TP_printk("flags: 0x%08x", __entry->guest_debug) +); + +TRACE_EVENT(kvm_arch_clear_debug, + TP_PROTO(__u32 guest_debug), + TP_ARGS(guest_debug), + + TP_STRUCT__entry( + __field(__u32, guest_debug) + ), + + TP_fast_assign( + __entry->guest_debug = guest_debug; + ), + + TP_printk("flags: 0x%08x", __entry->guest_debug) +); + +TRACE_EVENT(kvm_arch_setup_debug_reg32, + TP_PROTO(const char *name, __u32 value), + TP_ARGS(name, value), + + TP_STRUCT__entry( + __field(const char *, name) + __field(__u32, value) + ), + + TP_fast_assign( + __entry->name = name; + __entry->value = value; + ), + + TP_printk("%s now 0x%08x", __entry->name, __entry->value) +); + #endif /* _TRACE_ARM64_KVM_H */ #undef TRACE_INCLUDE_PATH
This includes trace points for: kvm_arch_setup_guest_debug kvm_arch_clear_guest_debug kvm_handle_guest_debug I've also added some generic register setting trace events so I can watch the register values being built up over time. The local dump_dbg_regs() function dumps all the HW BKPT and WPT registers. I've also added a #define trace_dreg to shorten some lines. Signed-off-by: Alex Bennée <alex.bennee@linaro.org>