KVM: PPC: e500: Add support for EPTCFG register

EPTCFG register defined by E.PT is accessed unconditionally by Linux guests
in the presence of MAV 2.0. Emulate it now.

Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

Documentation/virtual/kvm/api.txt

@@ -1807,6 +1807,7 @@ registers, find a list below:
   PPC   | KVM_REG_PPC_TLB1PS	| 32
   PPC   | KVM_REG_PPC_TLB2PS	| 32
   PPC   | KVM_REG_PPC_TLB3PS	| 32
+  PPC   | KVM_REG_PPC_EPTCFG	| 32
 
 ARM registers are mapped using the lower 32 bits.  The upper 16 of that
 is the register group type, or coprocessor number:

arch/powerpc/include/asm/kvm_host.h

@@ -504,6 +504,7 @@ struct kvm_vcpu_arch {
 	u32 tlbcfg[4];
 	u32 tlbps[4];
 	u32 mmucfg;
+	u32 eptcfg;
 	u32 epr;
 	u32 crit_save;
 	struct kvmppc_booke_debug_reg dbg_reg;

arch/powerpc/include/uapi/asm/kvm.h

@@ -469,5 +469,6 @@ struct kvm_get_htab_header {
 #define KVM_REG_PPC_TLB1PS	(KVM_REG_PPC | KVM_REG_SIZE_U32 | 0x98)
 #define KVM_REG_PPC_TLB2PS	(KVM_REG_PPC | KVM_REG_SIZE_U32 | 0x99)
 #define KVM_REG_PPC_TLB3PS	(KVM_REG_PPC | KVM_REG_SIZE_U32 | 0x9a)
+#define KVM_REG_PPC_EPTCFG	(KVM_REG_PPC | KVM_REG_SIZE_U32 | 0x9b)
 
 #endif /* __LINUX_KVM_POWERPC_H */

arch/powerpc/kvm/e500_emulate.c

@@ -317,6 +317,15 @@ int kvmppc_core_emulate_mfspr(struct kvm_vcpu *vcpu, int sprn, ulong *spr_val)
 	case SPRN_MMUCFG:
 		*spr_val = vcpu->arch.mmucfg;
 		break;
+	case SPRN_EPTCFG:
+		if (!has_feature(vcpu, VCPU_FTR_MMU_V2))
+			return EMULATE_FAIL;
+		/*
+		 * Legacy Linux guests access EPTCFG register even if the E.PT
+		 * category is disabled in the VM. Give them a chance to live.
+		 */
+		*spr_val = vcpu->arch.eptcfg;
+		break;
 
 	/* extra exceptions */
 	case SPRN_IVOR32:

arch/powerpc/kvm/e500_mmu.c

@@ -624,6 +624,9 @@ int kvmppc_get_one_reg_e500_tlb(struct kvm_vcpu *vcpu, u64 id,
 	case KVM_REG_PPC_MMUCFG:
 		*val = get_reg_val(id, vcpu->arch.mmucfg);
 		break;
+	case KVM_REG_PPC_EPTCFG:
+		*val = get_reg_val(id, vcpu->arch.eptcfg);
+		break;
 	case KVM_REG_PPC_TLB0CFG:
 	case KVM_REG_PPC_TLB1CFG:
 	case KVM_REG_PPC_TLB2CFG:
@@ -678,6 +681,12 @@ int kvmppc_set_one_reg_e500_tlb(struct kvm_vcpu *vcpu, u64 id,
 			r = -EINVAL;
 		break;
 	}
+	case KVM_REG_PPC_EPTCFG: {
+		u32 reg = set_reg_val(id, *val);
+		if (reg != vcpu->arch.eptcfg)
+			r = -EINVAL;
+		break;
+	}
 	case KVM_REG_PPC_TLB0CFG:
 	case KVM_REG_PPC_TLB1CFG:
 	case KVM_REG_PPC_TLB2CFG:
@@ -875,6 +884,9 @@ static int vcpu_mmu_init(struct kvm_vcpu *vcpu,
 	if (has_feature(vcpu, VCPU_FTR_MMU_V2)) {
 		vcpu->arch.tlbps[0] = mfspr(SPRN_TLB0PS);
 		vcpu->arch.tlbps[1] = mfspr(SPRN_TLB1PS);
+
+		/* Guest mmu emulation currently doesn't handle E.PT */
+		vcpu->arch.eptcfg = 0;
 	}
 
 	return 0;