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@xxxxxxxxxx> 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 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html