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 <[email protected]> > > 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 [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
