Merge branch kvm-arm64/aarch32-idreg-trap into kvmarm-master/next

* kvm-arm64/aarch32-idreg-trap:
  : .
  : Add trapping/sanitising infrastructure for AArch32 systen registers,
  : allowing more control over what we actually expose (such as the PMU).
  :
  : Patches courtesy of Oliver and Alexandru.
  : .
  KVM: arm64: Fix new instances of 32bit ESRs
  KVM: arm64: Hide AArch32 PMU registers when not available
  KVM: arm64: Start trapping ID registers for 32 bit guests
  KVM: arm64: Plumb cp10 ID traps through the AArch64 sysreg handler
  KVM: arm64: Wire up CP15 feature registers to their AArch64 equivalents
  KVM: arm64: Don't write to Rt unless sys_reg emulation succeeds
  KVM: arm64: Return a bool from emulate_cp()
Signed-off-by: Marc Zyngier <maz@kernel.org>

arch/arm64/include/asm/kvm_arm.h

@@ -80,11 +80,12 @@
  * FMO:		Override CPSR.F and enable signaling with VF
  * SWIO:	Turn set/way invalidates into set/way clean+invalidate
  * PTW:		Take a stage2 fault if a stage1 walk steps in device memory
+ * TID3:	Trap EL1 reads of group 3 ID registers
  */
 #define HCR_GUEST_FLAGS (HCR_TSC | HCR_TSW | HCR_TWE | HCR_TWI | HCR_VM | \
 			 HCR_BSU_IS | HCR_FB | HCR_TACR | \
 			 HCR_AMO | HCR_SWIO | HCR_TIDCP | HCR_RW | HCR_TLOR | \
-			 HCR_FMO | HCR_IMO | HCR_PTW )
+			 HCR_FMO | HCR_IMO | HCR_PTW | HCR_TID3 )
 #define HCR_VIRT_EXCP_MASK (HCR_VSE | HCR_VI | HCR_VF)
 #define HCR_HOST_NVHE_FLAGS (HCR_RW | HCR_API | HCR_APK | HCR_ATA)
 #define HCR_HOST_NVHE_PROTECTED_FLAGS (HCR_HOST_NVHE_FLAGS | HCR_TSC)

arch/arm64/include/asm/kvm_emulate.h

@@ -87,13 +87,6 @@ static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu)
 
 	if (vcpu_el1_is_32bit(vcpu))
 		vcpu->arch.hcr_el2 &= ~HCR_RW;
-	else
-		/*
-		 * TID3: trap feature register accesses that we virtualise.
-		 * For now this is conditional, since no AArch32 feature regs
-		 * are currently virtualised.
-		 */
-		vcpu->arch.hcr_el2 |= HCR_TID3;
 
 	if (cpus_have_const_cap(ARM64_MISMATCHED_CACHE_TYPE) ||
 	    vcpu_el1_is_32bit(vcpu))

arch/arm64/include/asm/kvm_host.h

@@ -688,6 +688,7 @@ int kvm_handle_cp14_64(struct kvm_vcpu *vcpu);
 int kvm_handle_cp15_32(struct kvm_vcpu *vcpu);
 int kvm_handle_cp15_64(struct kvm_vcpu *vcpu);
 int kvm_handle_sys_reg(struct kvm_vcpu *vcpu);
+int kvm_handle_cp10_id(struct kvm_vcpu *vcpu);
 
 void kvm_reset_sys_regs(struct kvm_vcpu *vcpu);
 

arch/arm64/kvm/handle_exit.c

@@ -194,6 +194,7 @@ static exit_handle_fn arm_exit_handlers[] = {
 	[ESR_ELx_EC_CP15_64]	= kvm_handle_cp15_64,
 	[ESR_ELx_EC_CP14_MR]	= kvm_handle_cp14_32,
 	[ESR_ELx_EC_CP14_LS]	= kvm_handle_cp14_load_store,
+	[ESR_ELx_EC_CP10_ID]	= kvm_handle_cp10_id,
 	[ESR_ELx_EC_CP14_64]	= kvm_handle_cp14_64,
 	[ESR_ELx_EC_HVC32]	= handle_hvc,
 	[ESR_ELx_EC_SMC32]	= handle_smc,

arch/arm64/kvm/sys_regs.c

@@ -2023,20 +2023,22 @@ static const struct sys_reg_desc cp14_64_regs[] = {
 	{ Op1( 0), CRm( 2), .access = trap_raz_wi },
 };
 
+#define CP15_PMU_SYS_REG(_map, _Op1, _CRn, _CRm, _Op2)			\
+	AA32(_map),							\
+	Op1(_Op1), CRn(_CRn), CRm(_CRm), Op2(_Op2),			\
+	.visibility = pmu_visibility
+
 /* Macro to expand the PMEVCNTRn register */
 #define PMU_PMEVCNTR(n)							\
-	/* PMEVCNTRn */							\
-	{ Op1(0), CRn(0b1110),						\
-	  CRm((0b1000 | (((n) >> 3) & 0x3))), Op2(((n) & 0x7)),		\
-	  access_pmu_evcntr }
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 0b1110,				\
+	  (0b1000 | (((n) >> 3) & 0x3)), ((n) & 0x7)),			\
+	  .access = access_pmu_evcntr }
 
 /* Macro to expand the PMEVTYPERn register */
 #define PMU_PMEVTYPER(n)						\
-	/* PMEVTYPERn */						\
-	{ Op1(0), CRn(0b1110),						\
-	  CRm((0b1100 | (((n) >> 3) & 0x3))), Op2(((n) & 0x7)),		\
-	  access_pmu_evtyper }
-
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 0b1110,				\
+	  (0b1100 | (((n) >> 3) & 0x3)), ((n) & 0x7)),			\
+	  .access = access_pmu_evtyper }
 /*
  * Trapped cp15 registers. TTBR0/TTBR1 get a double encoding,
  * depending on the way they are accessed (as a 32bit or a 64bit
@@ -2076,25 +2078,25 @@ static const struct sys_reg_desc cp15_regs[] = {
 	{ Op1( 0), CRn( 7), CRm(14), Op2( 2), access_dcsw },
 
 	/* PMU */
-	{ Op1( 0), CRn( 9), CRm(12), Op2( 0), access_pmcr },
-	{ Op1( 0), CRn( 9), CRm(12), Op2( 1), access_pmcnten },
-	{ Op1( 0), CRn( 9), CRm(12), Op2( 2), access_pmcnten },
-	{ Op1( 0), CRn( 9), CRm(12), Op2( 3), access_pmovs },
-	{ Op1( 0), CRn( 9), CRm(12), Op2( 4), access_pmswinc },
-	{ Op1( 0), CRn( 9), CRm(12), Op2( 5), access_pmselr },
-	{ AA32(LO), Op1( 0), CRn( 9), CRm(12), Op2( 6), access_pmceid },
-	{ AA32(LO), Op1( 0), CRn( 9), CRm(12), Op2( 7), access_pmceid },
-	{ Op1( 0), CRn( 9), CRm(13), Op2( 0), access_pmu_evcntr },
-	{ Op1( 0), CRn( 9), CRm(13), Op2( 1), access_pmu_evtyper },
-	{ Op1( 0), CRn( 9), CRm(13), Op2( 2), access_pmu_evcntr },
-	{ Op1( 0), CRn( 9), CRm(14), Op2( 0), access_pmuserenr },
-	{ Op1( 0), CRn( 9), CRm(14), Op2( 1), access_pminten },
-	{ Op1( 0), CRn( 9), CRm(14), Op2( 2), access_pminten },
-	{ Op1( 0), CRn( 9), CRm(14), Op2( 3), access_pmovs },
-	{ AA32(HI), Op1( 0), CRn( 9), CRm(14), Op2( 4), access_pmceid },
-	{ AA32(HI), Op1( 0), CRn( 9), CRm(14), Op2( 5), access_pmceid },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 12, 0), .access = access_pmcr },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 12, 1), .access = access_pmcnten },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 12, 2), .access = access_pmcnten },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 12, 3), .access = access_pmovs },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 12, 4), .access = access_pmswinc },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 12, 5), .access = access_pmselr },
+	{ CP15_PMU_SYS_REG(LO,     0, 9, 12, 6), .access = access_pmceid },
+	{ CP15_PMU_SYS_REG(LO,     0, 9, 12, 7), .access = access_pmceid },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 13, 0), .access = access_pmu_evcntr },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 13, 1), .access = access_pmu_evtyper },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 13, 2), .access = access_pmu_evcntr },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 14, 0), .access = access_pmuserenr },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 14, 1), .access = access_pminten },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 14, 2), .access = access_pminten },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 14, 3), .access = access_pmovs },
+	{ CP15_PMU_SYS_REG(HI,     0, 9, 14, 4), .access = access_pmceid },
+	{ CP15_PMU_SYS_REG(HI,     0, 9, 14, 5), .access = access_pmceid },
 	/* PMMIR */
-	{ Op1( 0), CRn( 9), CRm(14), Op2( 6), trap_raz_wi },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 14, 6), .access = trap_raz_wi },
 
 	/* PRRR/MAIR0 */
 	{ AA32(LO), Op1( 0), CRn(10), CRm( 2), Op2( 0), access_vm_reg, NULL, MAIR_EL1 },
@@ -2179,7 +2181,7 @@ static const struct sys_reg_desc cp15_regs[] = {
 	PMU_PMEVTYPER(29),
 	PMU_PMEVTYPER(30),
 	/* PMCCFILTR */
-	{ Op1(0), CRn(14), CRm(15), Op2(7), access_pmu_evtyper },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 14, 15, 7), .access = access_pmu_evtyper },
 
 	{ Op1(1), CRn( 0), CRm( 0), Op2(0), access_ccsidr },
 	{ Op1(1), CRn( 0), CRm( 0), Op2(1), access_clidr },
@@ -2188,7 +2190,7 @@ static const struct sys_reg_desc cp15_regs[] = {
 
 static const struct sys_reg_desc cp15_64_regs[] = {
 	{ Op1( 0), CRn( 0), CRm( 2), Op2( 0), access_vm_reg, NULL, TTBR0_EL1 },
-	{ Op1( 0), CRn( 0), CRm( 9), Op2( 0), access_pmu_evcntr },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 0, 9, 0), .access = access_pmu_evcntr },
 	{ Op1( 0), CRn( 0), CRm(12), Op2( 0), access_gic_sgi }, /* ICC_SGI1R */
 	{ Op1( 1), CRn( 0), CRm( 2), Op2( 0), access_vm_reg, NULL, TTBR1_EL1 },
 	{ Op1( 1), CRn( 0), CRm(12), Op2( 0), access_gic_sgi }, /* ICC_ASGI1R */
@@ -2255,9 +2257,9 @@ static void perform_access(struct kvm_vcpu *vcpu,
  * @table: array of trap descriptors
  * @num: size of the trap descriptor array
  *
- * Return 0 if the access has been handled, and -1 if not.
+ * Return true if the access has been handled, false if not.
  */
-static int emulate_cp(struct kvm_vcpu *vcpu,
+static bool emulate_cp(struct kvm_vcpu *vcpu,
 		       struct sys_reg_params *params,
 		       const struct sys_reg_desc *table,
 		       size_t num)
@@ -2265,17 +2267,17 @@ static int emulate_cp(struct kvm_vcpu *vcpu,
 	const struct sys_reg_desc *r;
 
 	if (!table)
-		return -1;	/* Not handled */
+		return false;	/* Not handled */
 
 	r = find_reg(params, table, num);
 
 	if (r) {
 		perform_access(vcpu, params, r);
-		return 0;
+		return true;
 	}
 
 	/* Not handled */
-	return -1;
+	return false;
 }
 
 static void unhandled_cp_access(struct kvm_vcpu *vcpu,
@@ -2313,7 +2315,7 @@ static int kvm_handle_cp_64(struct kvm_vcpu *vcpu,
 			    size_t nr_global)
 {
 	struct sys_reg_params params;
-	u32 esr = kvm_vcpu_get_esr(vcpu);
+	u64 esr = kvm_vcpu_get_esr(vcpu);
 	int Rt = kvm_vcpu_sys_get_rt(vcpu);
 	int Rt2 = (esr >> 10) & 0x1f;
 
@@ -2339,7 +2341,7 @@ static int kvm_handle_cp_64(struct kvm_vcpu *vcpu,
 	 * potential register operation in the case of a read and return
 	 * with success.
 	 */
-	if (!emulate_cp(vcpu, &params, global, nr_global)) {
+	if (emulate_cp(vcpu, &params, global, nr_global)) {
 		/* Split up the value between registers for the read side */
 		if (!params.is_write) {
 			vcpu_set_reg(vcpu, Rt, lower_32_bits(params.regval));
@@ -2353,34 +2355,144 @@ static int kvm_handle_cp_64(struct kvm_vcpu *vcpu,
 	return 1;
 }
 
+static bool emulate_sys_reg(struct kvm_vcpu *vcpu, struct sys_reg_params *params);
+
+/*
+ * The CP10 ID registers are architecturally mapped to AArch64 feature
+ * registers. Abuse that fact so we can rely on the AArch64 handler for accesses
+ * from AArch32.
+ */
+static bool kvm_esr_cp10_id_to_sys64(u64 esr, struct sys_reg_params *params)
+{
+	u8 reg_id = (esr >> 10) & 0xf;
+	bool valid;
+
+	params->is_write = ((esr & 1) == 0);
+	params->Op0 = 3;
+	params->Op1 = 0;
+	params->CRn = 0;
+	params->CRm = 3;
+
+	/* CP10 ID registers are read-only */
+	valid = !params->is_write;
+
+	switch (reg_id) {
+	/* MVFR0 */
+	case 0b0111:
+		params->Op2 = 0;
+		break;
+	/* MVFR1 */
+	case 0b0110:
+		params->Op2 = 1;
+		break;
+	/* MVFR2 */
+	case 0b0101:
+		params->Op2 = 2;
+		break;
+	default:
+		valid = false;
+	}
+
+	if (valid)
+		return true;
+
+	kvm_pr_unimpl("Unhandled cp10 register %s: %u\n",
+		      params->is_write ? "write" : "read", reg_id);
+	return false;
+}
+
+/**
+ * kvm_handle_cp10_id() - Handles a VMRS trap on guest access to a 'Media and
+ *			  VFP Register' from AArch32.
+ * @vcpu: The vCPU pointer
+ *
+ * MVFR{0-2} are architecturally mapped to the AArch64 MVFR{0-2}_EL1 registers.
+ * Work out the correct AArch64 system register encoding and reroute to the
+ * AArch64 system register emulation.
+ */
+int kvm_handle_cp10_id(struct kvm_vcpu *vcpu)
+{
+	int Rt = kvm_vcpu_sys_get_rt(vcpu);
+	u64 esr = kvm_vcpu_get_esr(vcpu);
+	struct sys_reg_params params;
+
+	/* UNDEF on any unhandled register access */
+	if (!kvm_esr_cp10_id_to_sys64(esr, &params)) {
+		kvm_inject_undefined(vcpu);
+		return 1;
+	}
+
+	if (emulate_sys_reg(vcpu, &params))
+		vcpu_set_reg(vcpu, Rt, params.regval);
+
+	return 1;
+}
+
+/**
+ * kvm_emulate_cp15_id_reg() - Handles an MRC trap on a guest CP15 access where
+ *			       CRn=0, which corresponds to the AArch32 feature
+ *			       registers.
+ * @vcpu: the vCPU pointer
+ * @params: the system register access parameters.
+ *
+ * Our cp15 system register tables do not enumerate the AArch32 feature
+ * registers. Conveniently, our AArch64 table does, and the AArch32 system
+ * register encoding can be trivially remapped into the AArch64 for the feature
+ * registers: Append op0=3, leaving op1, CRn, CRm, and op2 the same.
+ *
+ * According to DDI0487G.b G7.3.1, paragraph "Behavior of VMSAv8-32 32-bit
+ * System registers with (coproc=0b1111, CRn==c0)", read accesses from this
+ * range are either UNKNOWN or RES0. Rerouting remains architectural as we
+ * treat undefined registers in this range as RAZ.
+ */
+static int kvm_emulate_cp15_id_reg(struct kvm_vcpu *vcpu,
+				   struct sys_reg_params *params)
+{
+	int Rt = kvm_vcpu_sys_get_rt(vcpu);
+
+	/* Treat impossible writes to RO registers as UNDEFINED */
+	if (params->is_write) {
+		unhandled_cp_access(vcpu, params);
+		return 1;
+	}
+
+	params->Op0 = 3;
+
+	/*
+	 * All registers where CRm > 3 are known to be UNKNOWN/RAZ from AArch32.
+	 * Avoid conflicting with future expansion of AArch64 feature registers
+	 * and simply treat them as RAZ here.
+	 */
+	if (params->CRm > 3)
+		params->regval = 0;
+	else if (!emulate_sys_reg(vcpu, params))
+		return 1;
+
+	vcpu_set_reg(vcpu, Rt, params->regval);
+	return 1;
+}
+
 /**
  * kvm_handle_cp_32 -- handles a mrc/mcr trap on a guest CP14/CP15 access
  * @vcpu: The VCPU pointer
  * @run:  The kvm_run struct
  */
 static int kvm_handle_cp_32(struct kvm_vcpu *vcpu,
+			    struct sys_reg_params *params,
 			    const struct sys_reg_desc *global,
 			    size_t nr_global)
 {
-	struct sys_reg_params params;
-	u32 esr = kvm_vcpu_get_esr(vcpu);
 	int Rt  = kvm_vcpu_sys_get_rt(vcpu);
 
-	params.CRm = (esr >> 1) & 0xf;
-	params.regval = vcpu_get_reg(vcpu, Rt);
-	params.is_write = ((esr & 1) == 0);
-	params.CRn = (esr >> 10) & 0xf;
-	params.Op0 = 0;
-	params.Op1 = (esr >> 14) & 0x7;
-	params.Op2 = (esr >> 17) & 0x7;
+	params->regval = vcpu_get_reg(vcpu, Rt);
 
-	if (!emulate_cp(vcpu, &params, global, nr_global)) {
-		if (!params.is_write)
-			vcpu_set_reg(vcpu, Rt, params.regval);
+	if (emulate_cp(vcpu, params, global, nr_global)) {
+		if (!params->is_write)
+			vcpu_set_reg(vcpu, Rt, params->regval);
 		return 1;
 	}
 
-	unhandled_cp_access(vcpu, &params);
+	unhandled_cp_access(vcpu, params);
 	return 1;
 }
 
@@ -2391,7 +2503,20 @@ int kvm_handle_cp15_64(struct kvm_vcpu *vcpu)
 
 int kvm_handle_cp15_32(struct kvm_vcpu *vcpu)
 {
-	return kvm_handle_cp_32(vcpu, cp15_regs, ARRAY_SIZE(cp15_regs));
+	struct sys_reg_params params;
+
+	params = esr_cp1x_32_to_params(kvm_vcpu_get_esr(vcpu));
+
+	/*
+	 * Certain AArch32 ID registers are handled by rerouting to the AArch64
+	 * system register table. Registers in the ID range where CRm=0 are
+	 * excluded from this scheme as they do not trivially map into AArch64
+	 * system register encodings.
+	 */
+	if (params.Op1 == 0 && params.CRn == 0 && params.CRm)
+		return kvm_emulate_cp15_id_reg(vcpu, &params);
+
+	return kvm_handle_cp_32(vcpu, &params, cp15_regs, ARRAY_SIZE(cp15_regs));
 }
 
 int kvm_handle_cp14_64(struct kvm_vcpu *vcpu)
@@ -2401,7 +2526,11 @@ int kvm_handle_cp14_64(struct kvm_vcpu *vcpu)
 
 int kvm_handle_cp14_32(struct kvm_vcpu *vcpu)
 {
-	return kvm_handle_cp_32(vcpu, cp14_regs, ARRAY_SIZE(cp14_regs));
+	struct sys_reg_params params;
+
+	params = esr_cp1x_32_to_params(kvm_vcpu_get_esr(vcpu));
+
+	return kvm_handle_cp_32(vcpu, &params, cp14_regs, ARRAY_SIZE(cp14_regs));
 }
 
 static bool is_imp_def_sys_reg(struct sys_reg_params *params)
@@ -2410,7 +2539,14 @@ static bool is_imp_def_sys_reg(struct sys_reg_params *params)
 	return params->Op0 == 3 && (params->CRn & 0b1011) == 0b1011;
 }
 
-static int emulate_sys_reg(struct kvm_vcpu *vcpu,
+/**
+ * emulate_sys_reg - Emulate a guest access to an AArch64 system register
+ * @vcpu: The VCPU pointer
+ * @params: Decoded system register parameters
+ *
+ * Return: true if the system register access was successful, false otherwise.
+ */
+static bool emulate_sys_reg(struct kvm_vcpu *vcpu,
 			   struct sys_reg_params *params)
 {
 	const struct sys_reg_desc *r;
@@ -2419,7 +2555,10 @@ static int emulate_sys_reg(struct kvm_vcpu *vcpu,
 
 	if (likely(r)) {
 		perform_access(vcpu, params, r);
-	} else if (is_imp_def_sys_reg(params)) {
+		return true;
+	}
+
+	if (is_imp_def_sys_reg(params)) {
 		kvm_inject_undefined(vcpu);
 	} else {
 		print_sys_reg_msg(params,
@@ -2427,7 +2566,7 @@ static int emulate_sys_reg(struct kvm_vcpu *vcpu,
 				  *vcpu_pc(vcpu), *vcpu_cpsr(vcpu));
 		kvm_inject_undefined(vcpu);
 	}
-	return 1;
+	return false;
 }
 
 /**
@@ -2455,18 +2594,18 @@ int kvm_handle_sys_reg(struct kvm_vcpu *vcpu)
 	struct sys_reg_params params;
 	unsigned long esr = kvm_vcpu_get_esr(vcpu);
 	int Rt = kvm_vcpu_sys_get_rt(vcpu);
-	int ret;
 
 	trace_kvm_handle_sys_reg(esr);
 
 	params = esr_sys64_to_params(esr);
 	params.regval = vcpu_get_reg(vcpu, Rt);
 
-	ret = emulate_sys_reg(vcpu, &params);
+	if (!emulate_sys_reg(vcpu, &params))
+		return 1;
 
 	if (!params.is_write)
 		vcpu_set_reg(vcpu, Rt, params.regval);
-	return ret;
+	return 1;
 }
 
 /******************************************************************************

arch/arm64/kvm/sys_regs.h

@@ -35,12 +35,19 @@ struct sys_reg_params {
 				  .Op2 = ((esr) >> 17) & 0x7,                  \
 				  .is_write = !((esr) & 1) })
 
+#define esr_cp1x_32_to_params(esr)						\
+	((struct sys_reg_params){ .Op1 = ((esr) >> 14) & 0x7,			\
+				  .CRn = ((esr) >> 10) & 0xf,			\
+				  .CRm = ((esr) >> 1) & 0xf,			\
+				  .Op2 = ((esr) >> 17) & 0x7,			\
+				  .is_write = !((esr) & 1) })
+
 struct sys_reg_desc {
 	/* Sysreg string for debug */
 	const char *name;
 
 	enum {
-		AA32_ZEROHIGH,
+		AA32_DIRECT,
 		AA32_LO,
 		AA32_HI,
 	} aarch32_map;