Add handlers for all the 32-bit debug registers.

Signed-off-by: Zhichao Huang <redacted>
---
 arch/arm/include/asm/kvm_asm.h  |  12 ++++
 arch/arm/include/asm/kvm_host.h |   3 +
 arch/arm/kernel/asm-offsets.c   |   1 +
 arch/arm/kvm/coproc.c           | 122 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 138 insertions(+)

diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
index 25410b2..ba65e05 100644
--- a/arch/arm/include/asm/kvm_asm.h
+++ b/arch/arm/include/asm/kvm_asm.h

@@ -52,6 +52,18 @@
 #define c10_AMAIR1	30	/* Auxilary Memory Attribute Indirection Reg1 */
 #define NR_CP15_REGS	31	/* Number of regs (incl. invalid) */
 
+/* 0 is reserved as an invalid value. */
+#define cp14_DBGBVR0	1	/* Debug Breakpoint Control Registers (0-15) */
+#define cp14_DBGBVR15	16
+#define cp14_DBGBCR0	17	/* Debug Breakpoint Value Registers (0-15) */
+#define cp14_DBGBCR15	32
+#define cp14_DBGWVR0	33	/* Debug Watchpoint Control Registers (0-15) */
+#define cp14_DBGWVR15	48
+#define cp14_DBGWCR0	49	/* Debug Watchpoint Value Registers (0-15) */
+#define cp14_DBGWCR15	64
+#define cp14_DBGDSCRext	65	/* Debug Status and Control external */
+#define NR_CP14_REGS	66	/* Number of regs (incl. invalid) */
+
 #define ARM_EXCEPTION_RESET	  0
 #define ARM_EXCEPTION_UNDEFINED   1
 #define ARM_EXCEPTION_SOFTWARE    2

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index d71607c..3d16820 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h

@@ -124,6 +124,9 @@ struct kvm_vcpu_arch {
 	struct vgic_cpu vgic_cpu;
 	struct arch_timer_cpu timer_cpu;
 
+	/* System control coprocessor (cp14) */
+	u32 cp14[NR_CP14_REGS];
+
 	/*
 	 * Anything that is not used directly from assembly code goes
 	 * here.

diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c
index 871b826..9158de0 100644
--- a/arch/arm/kernel/asm-offsets.c
+++ b/arch/arm/kernel/asm-offsets.c

@@ -172,6 +172,7 @@ int main(void)
 #ifdef CONFIG_KVM_ARM_HOST
   DEFINE(VCPU_KVM,		offsetof(struct kvm_vcpu, kvm));
   DEFINE(VCPU_MIDR,		offsetof(struct kvm_vcpu, arch.midr));
+  DEFINE(VCPU_CP14,		offsetof(struct kvm_vcpu, arch.cp14));
   DEFINE(VCPU_CP15,		offsetof(struct kvm_vcpu, arch.cp15));
   DEFINE(VCPU_VFP_GUEST,	offsetof(struct kvm_vcpu, arch.vfp_guest));
   DEFINE(VCPU_VFP_HOST,		offsetof(struct kvm_vcpu, arch.host_cpu_context));

diff --git a/arch/arm/kvm/coproc.c b/arch/arm/kvm/coproc.c
index 16d5f69..59b65b7 100644
--- a/arch/arm/kvm/coproc.c
+++ b/arch/arm/kvm/coproc.c

@@ -220,6 +220,47 @@ bool access_vm_reg(struct kvm_vcpu *vcpu,
 	return true;
 }
 
+static bool trap_debug32(struct kvm_vcpu *vcpu,
+			const struct coproc_params *p,
+			const struct coproc_reg *r)
+{
+	if (p->is_write)
+		vcpu->arch.cp14[r->reg] = *vcpu_reg(vcpu, p->Rt1);
+	else
+		*vcpu_reg(vcpu, p->Rt1) = vcpu->arch.cp14[r->reg];
+
+	return true;
+}
+
+/* DBGIDR (RO) Debug ID */
+static bool trap_dbgidr(struct kvm_vcpu *vcpu,
+			const struct coproc_params *p,
+			const struct coproc_reg *r)
+{
+	u32 val;
+
+	if (p->is_write)
+		return ignore_write(vcpu, p);
+
+	ARM_DBG_READ(c0, c0, 0, val);
+	*vcpu_reg(vcpu, p->Rt1) = val;
+
+	return true;
+}
+
+/* DBGDSCRint (RO) Debug Status and Control Register */
+static bool trap_dbgdscr(struct kvm_vcpu *vcpu,
+			const struct coproc_params *p,
+			const struct coproc_reg *r)
+{
+	if (p->is_write)
+		return ignore_write(vcpu, p);
+
+	*vcpu_reg(vcpu, p->Rt1) = vcpu->arch.cp14[r->reg];
+
+	return true;
+}
+
 /*
  * We could trap ID_DFR0 and tell the guest we don't support performance
  * monitoring.  Unfortunately the patch to make the kernel check ID_DFR0 was

@@ -375,7 +416,88 @@ static const struct coproc_reg cp15_regs[] = {
 	{ CRn(15), CRm( 0), Op1( 4), Op2( 0), is32, access_cbar},
 };
 
+#define DBG_BCR_BVR_WCR_WVR(n)					\
+	/* DBGBVRn */						\
+	{ CRn( 0), CRm((n)), Op1( 0), Op2( 4), is32,		\
+	  trap_debug32,	reset_val, (cp14_DBGBVR0 + (n)), 0 },	\
+	/* DBGBCRn */						\
+	{ CRn( 0), CRm((n)), Op1( 0), Op2( 5), is32,		\
+	  trap_debug32,	reset_val, (cp14_DBGBCR0 + (n)), 0 },	\
+	/* DBGWVRn */						\
+	{ CRn( 0), CRm((n)), Op1( 0), Op2( 6), is32,		\
+	  trap_debug32,	reset_val, (cp14_DBGWVR0 + (n)), 0 },	\
+	/* DBGWCRn */						\
+	{ CRn( 0), CRm((n)), Op1( 0), Op2( 7), is32,		\
+	  trap_debug32,	reset_val, (cp14_DBGWCR0 + (n)), 0 }
+
+/* No OS DBGBXVR machanism implemented. */
+#define DBGBXVR(n)						\
+	{ CRn( 1), CRm((n)), Op1( 0), Op2( 1), is32, trap_raz_wi }
+
+/*
+ * Trapped cp14 registers. We generally ignore most of the external
+ * debug, on the principle that they don't really make sense to a
+ * guest. Revisit this one day, whould this principle change.