[PATCH v3 12/12] KVM: arm64: add trace points for guest_debug debug

[Alex BennÃe]

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 and also a
trace point to dump the array of hardware registers.

Signed-off-by: Alex BennÃe <alex.bennee@xxxxxxxxxx>

---
v3
  - add trace event for debug access.
  - remove short trace #define, rename trace events
  - use __print_array with fixed array instead of own func
  - rationalise trace points (only one per register changed)
  - add vcpu ptr to the debug_setup trace
  - remove :: in prints

diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c
index dc8bca8..08e1b83 100644
--- a/arch/arm64/kvm/debug.c
+++ b/arch/arm64/kvm/debug.c
@@ -24,6 +24,8 @@
 #include <asm/kvm_arm.h>
 #include <asm/kvm_emulate.h>
 
+#include "trace.h"
+
 /* These are the bits of MDSCR_EL1 we may manipulate */
 #define MDSCR_EL1_DEBUG_MASK	(DBG_MDSCR_SS | \
 				DBG_MDSCR_KDE | \
@@ -44,6 +46,11 @@ static void save_guest_debug_regs(struct kvm_vcpu *vcpu)
 {
 	vcpu->arch.guest_debug_state.pstate = *vcpu_cpsr(vcpu);
 	vcpu->arch.guest_debug_state.mdscr_el1 = vcpu_sys_reg(vcpu, MDSCR_EL1);
+
+	trace_kvm_arm_set_dreg32("Saved PSTATE",
+				vcpu->arch.guest_debug_state.pstate);
+	trace_kvm_arm_set_dreg32("Saved MDSCR_EL1",
+				vcpu->arch.guest_debug_state.mdscr_el1);
 }
 
 static void restore_guest_debug_regs(struct kvm_vcpu *vcpu)
@@ -51,6 +58,10 @@ static void restore_guest_debug_regs(struct kvm_vcpu *vcpu)
 	*vcpu_cpsr(vcpu) |=
 		(vcpu->arch.guest_debug_state.pstate & SPSR_DEBUG_MASK);
 	vcpu_sys_reg(vcpu, MDSCR_EL1) = vcpu->arch.guest_debug_state.mdscr_el1;
+
+	trace_kvm_arm_set_dreg32("Restored PSTATE", *vcpu_cpsr(vcpu));
+	trace_kvm_arm_set_dreg32("Restored MDSCR_EL1",
+				vcpu_sys_reg(vcpu, MDSCR_EL1));
 }
 
 /**
@@ -92,6 +103,8 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
 {
 	bool trap_debug = !(vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY);
 
+	trace_kvm_arm_setup_debug(vcpu, vcpu->guest_debug);
+
 	vcpu->arch.mdcr_el2 = __this_cpu_read(mdcr_el2) & MDCR_EL2_HPMN_MASK;
 	vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM |
 				MDCR_EL2_TPMCR |
@@ -121,6 +134,8 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
 			vcpu_sys_reg(vcpu, MDSCR_EL1) &= ~DBG_MDSCR_SS;
 		}
 
+		trace_kvm_arm_set_dreg32("SPSR_EL2", *vcpu_cpsr(vcpu));
+
 		/*
 		 * HW Break/Watch points
 		 *
@@ -138,6 +153,14 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
 			vcpu->arch.debug_ptr = &vcpu->arch.external_debug_state;
 			vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
 			trap_debug = true;
+
+			trace_kvm_arm_set_regset("BKPTS", get_num_brps(),
+						&vcpu->arch.debug_ptr->dbg_bcr[0],
+						&vcpu->arch.debug_ptr->dbg_bvr[0]);
+
+			trace_kvm_arm_set_regset("WAPTS", get_num_wrps(),
+						&vcpu->arch.debug_ptr->dbg_wcr[0],
+						&vcpu->arch.debug_ptr->dbg_wvr[0]);
 		}
 
 	} else {
@@ -155,10 +178,15 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
 		vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA;
 	else
 		vcpu->arch.mdcr_el2 &= ~MDCR_EL2_TDA;
+
+	trace_kvm_arm_set_dreg32("MDCR_EL2", vcpu->arch.mdcr_el2);
+	trace_kvm_arm_set_dreg32("MDSCR_EL1", vcpu_sys_reg(vcpu, MDSCR_EL1));
 }
 
 void kvm_arm_clear_debug(struct kvm_vcpu *vcpu)
 {
+	trace_kvm_arm_clear_debug(vcpu->guest_debug);
+
 	if (vcpu->guest_debug) {
 		restore_guest_debug_regs(vcpu);
 
@@ -169,6 +197,14 @@ void kvm_arm_clear_debug(struct kvm_vcpu *vcpu)
 		if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
 			vcpu->arch.debug_ptr = (struct kvm_guest_debug_arch *)
 				&vcpu_sys_reg(vcpu, DBGBCR0_EL1);
+
+			trace_kvm_arm_set_regset("BKPTS", get_num_brps(),
+						&vcpu->arch.debug_ptr->dbg_bcr[0],
+						&vcpu->arch.debug_ptr->dbg_bvr[0]);
+
+			trace_kvm_arm_set_regset("WAPTS", get_num_wrps(),
+						&vcpu->arch.debug_ptr->dbg_wcr[0],
+						&vcpu->arch.debug_ptr->dbg_wvr[0]);
 		}
 	}
 }
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index 68a0759..c93b95e 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -99,6 +99,8 @@ static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run)
 	u32 hsr = kvm_vcpu_get_hsr(vcpu);
 	int ret = 0;
 
+	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/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 95f422f..ec803ad 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -38,6 +38,8 @@
 
 #include "sys_regs.h"
 
+#include "trace.h"
+
 /*
  * All of this file is extremly similar to the ARM coproc.c, but the
  * types are different. My gut feeling is that it should be pretty
@@ -227,6 +229,9 @@ static bool trap_debug_regs(struct kvm_vcpu *vcpu,
 			    const struct sys_reg_params *p,
 			    const struct sys_reg_desc *r)
 {
+	trace_trap_debug_regs(r->reg, p->is_write,
+			p->is_write?*vcpu_reg(vcpu, p->Rt):0);
+
 	if (vcpu->guest_debug && shadow_debug_reg(vcpu, p, r))
 		return true;
 
diff --git a/arch/arm64/kvm/trace.h b/arch/arm64/kvm/trace.h
index 157416e9..62e6b76 100644
--- a/arch/arm64/kvm/trace.h
+++ b/arch/arm64/kvm/trace.h
@@ -44,6 +44,113 @@ 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_arm_setup_debug,
+	TP_PROTO(struct kvm_vcpu *vcpu, __u32 guest_debug),
+	TP_ARGS(vcpu, guest_debug),
+
+	TP_STRUCT__entry(
+		__field(struct kvm_vcpu *, vcpu)
+		__field(__u32, guest_debug)
+	),
+
+	TP_fast_assign(
+		__entry->vcpu = vcpu;
+		__entry->guest_debug = guest_debug;
+	),
+
+	TP_printk("vcpu: %p, flags: 0x%08x", __entry->vcpu, __entry->guest_debug)
+);
+
+TRACE_EVENT(kvm_arm_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_arm_set_dreg32,
+	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: 0x%08x", __entry->name, __entry->value)
+);
+
+TRACE_EVENT(kvm_arm_set_regset,
+	TP_PROTO(const char *type, int len, __u64 *control, __u64 *value),
+	TP_ARGS(type, len, control, value),
+	TP_STRUCT__entry(
+		__field(const char *, name)
+		__field(int, len)
+		__array(u64, ctrls, 16)
+		__array(u64, values, 16)
+	),
+	TP_fast_assign(
+		__entry->name = type;
+		__entry->len = len;
+		memcpy(__entry->ctrls, control, len << 3);
+		memcpy(__entry->values, value, len << 3);
+	),
+	TP_printk("%d %s CTRL:%s VALUE:%s", __entry->len, __entry->name,
+		__print_array(__entry->ctrls, __entry->len, sizeof(__u64)),
+		__print_array(__entry->values, __entry->len, sizeof(__u64)))
+);
+
+TRACE_EVENT(trap_debug_regs,
+	TP_PROTO(int reg, bool is_write, u64 write_value),
+	TP_ARGS(reg, is_write, write_value),
+
+	TP_STRUCT__entry(
+		__field(int, reg)
+		__field(bool, is_write)
+		__field(u64, write_value)
+	),
+
+	TP_fast_assign(
+		__entry->reg = reg;
+		__entry->is_write = is_write;
+		__entry->write_value = write_value;
+	),
+
+	TP_printk("%s reg %d (0x%08llx)", __entry->is_write?"write to":"read from", __entry->reg, __entry->write_value)
+);
+
 #endif /* _TRACE_ARM64_KVM_H */
 
 #undef TRACE_INCLUDE_PATH
-- 
2.3.5

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