On Wed, Jul 01, 2015 at 03:09:35PM +0800, zichao wrote:

On June 30, 2015 3:43:34 AM GMT+08:00, Christoffer Dall [off-list ref] wrote:

quoted

On Mon, Jun 22, 2015 at 06:41:27PM +0800, Zhichao Huang wrote:

quoted

As we're about to trap a bunch of CP14 registers, let's rework
the CP15 handling so it can be generalized and work with multiple
tables.

Signed-off-by: Zhichao Huang <redacted>
---
 arch/arm/kvm/coproc.c          | 176

++++++++++++++++++++++++++---------------

quoted

 arch/arm/kvm/interrupts_head.S |   2 +-
 2 files changed, 112 insertions(+), 66 deletions(-)

diff --git a/arch/arm/kvm/coproc.c b/arch/arm/kvm/coproc.c
index 9d283d9..d23395b 100644
--- a/arch/arm/kvm/coproc.c
+++ b/arch/arm/kvm/coproc.c

@@ -375,6 +375,9 @@ static const struct coproc_reg cp15_regs[] = {
 	{ CRn(15), CRm( 0), Op1( 4), Op2( 0), is32, access_cbar},
 };
 
+static const struct coproc_reg cp14_regs[] = {
+};
+
 /* Target specific emulation tables */
 static struct kvm_coproc_target_table

*target_tables[KVM_ARM_NUM_TARGETS];

quoted

@@ -424,47 +427,75 @@ static const struct coproc_reg *find_reg(const

struct coproc_params *params,

quoted

 	return NULL;
 }
 
-static int emulate_cp15(struct kvm_vcpu *vcpu,
-			const struct coproc_params *params)
+/*
+ * emulate_cp --  tries to match a cp14/cp15 access in a handling

table,

quoted

+ *                and call the corresponding trap handler.
+ *
+ * @params: pointer to the descriptor of the access
+ * @table: array of trap descriptors
+ * @num: size of the trap descriptor array
+ *
+ * Return 0 if the access has been handled, and -1 if not.
+ */
+static int emulate_cp(struct kvm_vcpu *vcpu,
+			const struct coproc_params *params,
+			const struct coproc_reg *table,
+			size_t num)
 {
-	size_t num;
-	const struct coproc_reg *table, *r;
-
-	trace_kvm_emulate_cp15_imp(params->Op1, params->Rt1, params->CRn,
-				   params->CRm, params->Op2, params->is_write);
+	const struct coproc_reg *r;
 
-	table = get_target_table(vcpu->arch.target, &num);
+	if (!table)
+		return -1;	/* Not handled */
 
-	/* Search target-specific then generic table. */
 	r = find_reg(params, table, num);
-	if (!r)
-		r = find_reg(params, cp15_regs, ARRAY_SIZE(cp15_regs));
 
-	if (likely(r)) {
+	if (r) {
 		/* If we don't have an accessor, we should never get here! */
 		BUG_ON(!r->access);
 
 		if (likely(r->access(vcpu, params, r))) {
 			/* Skip instruction, since it was emulated */
 			kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
-			return 1;
 		}
-		/* If access function fails, it should complain. */
-	} else {
-		kvm_err("Unsupported guest CP15 access at: %08lx\n",
-			*vcpu_pc(vcpu));
-		print_cp_instr(params);
+
+		/* Handled */
+		return 0;
 	}
+
+	/* Not handled */
+	return -1;
+}
+
+static void unhandled_cp_access(struct kvm_vcpu *vcpu,
+				const struct coproc_params *params)
+{
+	u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
+	int cp;
+
+	switch (hsr_ec) {
+	case HSR_EC_CP15_32:
+	case HSR_EC_CP15_64:
+		cp = 15;
+		break;
+	case HSR_EC_CP14_MR:
+	case HSR_EC_CP14_64:
+		cp = 14;
+		break;
+	default:
+		WARN_ON((cp = -1));
+	}
+
+	kvm_err("Unsupported guest CP%d access at: %08lx\n",
+		cp, *vcpu_pc(vcpu));
+	print_cp_instr(params);
 	kvm_inject_undefined(vcpu);
-	return 1;
 }
 
-/**
- * kvm_handle_cp15_64 -- handles a mrrc/mcrr trap on a guest CP15

access

quoted

- * @vcpu: The VCPU pointer
- * @run:  The kvm_run struct
- */
-int kvm_handle_cp15_64(struct kvm_vcpu *vcpu, struct kvm_run *run)
+int kvm_handle_cp_64(struct kvm_vcpu *vcpu,
+			const struct coproc_reg *global,
+			size_t nr_global,
+			const struct coproc_reg *target_specific,
+			size_t nr_specific)
 {
 	struct coproc_params params;
 

@@ -478,7 +509,13 @@ int kvm_handle_cp15_64(struct kvm_vcpu *vcpu,

struct kvm_run *run)

quoted

 	params.Rt2 = (kvm_vcpu_get_hsr(vcpu) >> 10) & 0xf;
 	params.CRm = 0;
 
-	return emulate_cp15(vcpu, &params);
+	if (!emulate_cp(vcpu, &params, target_specific, nr_specific))
+		return 1;
+	if (!emulate_cp(vcpu, &params, global, nr_global))
+		return 1;
+
+	unhandled_cp_access(vcpu, &params);
+	return 1;
 }
 
 static void reset_coproc_regs(struct kvm_vcpu *vcpu,

@@ -491,12 +528,11 @@ static void reset_coproc_regs(struct kvm_vcpu

*vcpu,

quoted

 			table[i].reset(vcpu, &table[i]);
 }
 
-/**
- * kvm_handle_cp15_32 -- handles a mrc/mcr trap on a guest CP15

access

quoted

- * @vcpu: The VCPU pointer
- * @run:  The kvm_run struct
- */
-int kvm_handle_cp15_32(struct kvm_vcpu *vcpu, struct kvm_run *run)
+int kvm_handle_cp_32(struct kvm_vcpu *vcpu,
+			const struct coproc_reg *global,
+			size_t nr_global,
+			const struct coproc_reg *target_specific,
+			size_t nr_specific)
 {
 	struct coproc_params params;
 

@@ -510,33 +546,57 @@ int kvm_handle_cp15_32(struct kvm_vcpu *vcpu,

struct kvm_run *run)

quoted

 	params.Op2 = (kvm_vcpu_get_hsr(vcpu) >> 17) & 0x7;
 	params.Rt2 = 0;
 
-	return emulate_cp15(vcpu, &params);
+	if (!emulate_cp(vcpu, &params, target_specific, nr_specific))
+		return 1;
+	if (!emulate_cp(vcpu, &params, global, nr_global))
+		return 1;
+
+	unhandled_cp_access(vcpu, &params);
+	return 1;
 }
 
 /**
- * kvm_handle_cp14_64 -- handles a mrrc/mcrr trap on a guest CP14

access

quoted

+ * kvm_handle_cp15_64 -- handles a mrrc/mcrr trap on a guest CP15

access

quoted

  * @vcpu: The VCPU pointer
  * @run:  The kvm_run struct
  */
-int kvm_handle_cp14_64(struct kvm_vcpu *vcpu, struct kvm_run *run)
+int kvm_handle_cp15_64(struct kvm_vcpu *vcpu, struct kvm_run *run)
 {
-	struct coproc_params params;
+	const struct coproc_reg *target_specific;
+	size_t num;
 
-	params.CRn = (kvm_vcpu_get_hsr(vcpu) >> 1) & 0xf;
-	params.Rt1 = (kvm_vcpu_get_hsr(vcpu) >> 5) & 0xf;
-	params.is_write = ((kvm_vcpu_get_hsr(vcpu) & 1) == 0);
-	params.is_64bit = true;
+	target_specific = get_target_table(vcpu->arch.target, &num);
+	return kvm_handle_cp_64(vcpu,
+				cp15_regs, ARRAY_SIZE(cp15_regs),
+				target_specific, num);
+}
 
-	params.Op1 = (kvm_vcpu_get_hsr(vcpu) >> 16) & 0xf;
-	params.Op2 = 0;
-	params.Rt2 = (kvm_vcpu_get_hsr(vcpu) >> 10) & 0xf;
-	params.CRm = 0;
+/**
+ * kvm_handle_cp15_32 -- handles a mrc/mcr trap on a guest CP15

access

quoted

+ * @vcpu: The VCPU pointer
+ * @run:  The kvm_run struct
+ */
+int kvm_handle_cp15_32(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+	const struct coproc_reg *target_specific;
+	size_t num;
 
-	(void)trap_raz_wi(vcpu, &params, NULL);
+	target_specific = get_target_table(vcpu->arch.target, &num);
+	return kvm_handle_cp_32(vcpu,
+				cp15_regs, ARRAY_SIZE(cp15_regs),
+				target_specific, num);
+}
 
-	/* handled */
-	kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
-	return 1;
+/**
+ * kvm_handle_cp14_64 -- handles a mrrc/mcrr trap on a guest CP14

access

quoted

+ * @vcpu: The VCPU pointer
+ * @run:  The kvm_run struct
+ */
+int kvm_handle_cp14_64(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+	return kvm_handle_cp_64(vcpu,
+				cp14_regs, ARRAY_SIZE(cp14_regs),
+				NULL, 0);
 }
 
 /**

@@ -546,23 +606,9 @@ int kvm_handle_cp14_64(struct kvm_vcpu *vcpu,

struct kvm_run *run)

quoted

  */
 int kvm_handle_cp14_32(struct kvm_vcpu *vcpu, struct kvm_run *run)
 {
-	struct coproc_params params;
-
-	params.CRm = (kvm_vcpu_get_hsr(vcpu) >> 1) & 0xf;
-	params.Rt1 = (kvm_vcpu_get_hsr(vcpu) >> 5) & 0xf;
-	params.is_write = ((kvm_vcpu_get_hsr(vcpu) & 1) == 0);
-	params.is_64bit = false;
-
-	params.CRn = (kvm_vcpu_get_hsr(vcpu) >> 10) & 0xf;
-	params.Op1 = (kvm_vcpu_get_hsr(vcpu) >> 14) & 0x7;
-	params.Op2 = (kvm_vcpu_get_hsr(vcpu) >> 17) & 0x7;
-	params.Rt2 = 0;
-
-	(void)trap_raz_wi(vcpu, &params, NULL);
-
-	/* handled */
-	kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
-	return 1;
+	return kvm_handle_cp_32(vcpu,
+				cp14_regs, ARRAY_SIZE(cp14_regs),
+				NULL, 0);
 }
 

/******************************************************************************

quoted

diff --git a/arch/arm/kvm/interrupts_head.S

b/arch/arm/kvm/interrupts_head.S

quoted

index f85c447..a20b9ad 100644

--- a/arch/arm/kvm/interrupts_head.S
+++ b/arch/arm/kvm/interrupts_head.S

@@ -618,7 +618,7 @@ ARM_BE8(rev	r6, r6  )
  * (hardware reset value is 0) */
 .macro set_hdcr operation
 	mrc	p15, 4, r2, c1, c1, 1
-	ldr	r3, =(HDCR_TPM|HDCR_TPMCR|HDCR_TDRA|HDCR_TDOSA|HDCR_TDA)
+	ldr	r3, =(HDCR_TPM|HDCR_TPMCR)

why do we stop trapping accesses here?

Because we didn't finish our trap handlers yet, if we keep the trapping enable here, the vm would not run normally as we use unhandled_cp_access in the trap handlers instead of trap_raz_wi.

I enable trapping until everything is ok, in the last patch [11/11].

ok, I see.  Feels a bit quirky, but ok.

-Christoffer