KVM: arm64: add trace points for guest_debug debug

This includes trace points for:
  kvm_arch_setup_guest_debug
  kvm_arch_clear_guest_debug

I've also added some generic register setting trace events and also a
trace point to dump the array of hardware registers.

Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

1 files changed, 35 insertions, 1 deletions

diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c
index 4a99e54d7f3d..47e5f0feaee8 100644
--- a/arch/arm64/kvm/debug.c
+++ b/arch/arm64/kvm/debug.c
@@ -18,12 +18,15 @@
  */
 
 #include <linux/kvm_host.h>
+#include <linux/hw_breakpoint.h>
 
 #include <asm/debug-monitors.h>
 #include <asm/kvm_asm.h>
 #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 | \
@@ -44,11 +47,17 @@ static DEFINE_PER_CPU(u32, mdcr_el2);
 static void save_guest_debug_regs(struct kvm_vcpu *vcpu)
 {
 	vcpu->arch.guest_debug_preserved.mdscr_el1 = vcpu_sys_reg(vcpu, MDSCR_EL1);
+
+	trace_kvm_arm_set_dreg32("Saved MDSCR_EL1",
+				vcpu->arch.guest_debug_preserved.mdscr_el1);
 }
 
 static void restore_guest_debug_regs(struct kvm_vcpu *vcpu)
 {
 	vcpu_sys_reg(vcpu, MDSCR_EL1) = vcpu->arch.guest_debug_preserved.mdscr_el1;
+
+	trace_kvm_arm_set_dreg32("Restored MDSCR_EL1",
+				vcpu_sys_reg(vcpu, MDSCR_EL1));
 }
 
 /**
@@ -99,6 +108,8 @@ 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 |
@@ -140,6 +151,8 @@ 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 Breakpoints and watchpoints
 		 *
@@ -156,6 +169,14 @@ 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]);
 		}
 	}
 
@@ -165,10 +186,15 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
 	/* Trap debug register access */
 	if (trap_debug)
 		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);
 
@@ -176,8 +202,16 @@ void kvm_arm_clear_debug(struct kvm_vcpu *vcpu)
 		 * If we were using HW debug we need to restore the
 		 * debug_ptr to the guest debug state.
 		 */
-		if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW)
+		if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW) {
 			kvm_arm_reset_debug_ptr(vcpu);
 
+			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]);
+		}
 	}
 }