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>

5 files changed, 24 insertions, 0 deletions

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index f045377ae5a0..a1f2200e43d0 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/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:
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 3b6cee3e33a8..8a48e686a755 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/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;
diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
index 4dd36c399842..41d59d8bdfe8 100644
--- a/arch/powerpc/include/uapi/asm/kvm.h
+++ b/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 */
diff --git a/arch/powerpc/kvm/e500_emulate.c b/arch/powerpc/kvm/e500_emulate.c
index 12b8de2f91ed..b10a01243abd 100644
--- a/arch/powerpc/kvm/e500_emulate.c
+++ b/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:
diff --git a/arch/powerpc/kvm/e500_mmu.c b/arch/powerpc/kvm/e500_mmu.c
index a863dc1791eb..1c1c5cb78495 100644
--- a/arch/powerpc/kvm/e500_mmu.c
+++ b/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;