KVM: PPC: Magic Page Book3s support

We need to override EA as well as PA lookups for the magic page. When the guest
tells us to project it, the magic page overrides any guest mappings.

In order to reflect that, we need to hook into all the MMU layers of KVM to
force map the magic page if necessary.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 29 insertions, 1 deletions

diff --git a/arch/powerpc/kvm/book3s_64_mmu.c b/arch/powerpc/kvm/book3s_64_mmu.c
index 58aa8409dae0..d7889ef3211e 100644
--- a/arch/powerpc/kvm/book3s_64_mmu.c
+++ b/arch/powerpc/kvm/book3s_64_mmu.c
@@ -163,6 +163,22 @@ static int kvmppc_mmu_book3s_64_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
         bool found = false;
         bool perm_err = false;
         int second = 0;
+        ulong mp_ea = vcpu->arch.magic_page_ea;
+
+        /* Magic page override */
+        if (unlikely(mp_ea) &&
+            unlikely((eaddr & ~0xfffULL) == (mp_ea & ~0xfffULL)) &&
+            !(vcpu->arch.shared->msr & MSR_PR)) {
+                gpte->eaddr = eaddr;
+                gpte->vpage = kvmppc_mmu_book3s_64_ea_to_vp(vcpu, eaddr, data);
+                gpte->raddr = vcpu->arch.magic_page_pa | (gpte->raddr & 0xfff);
+                gpte->raddr &= KVM_PAM;
+                gpte->may_execute = true;
+                gpte->may_read = true;
+                gpte->may_write = true;
+
+                return 0;
+        }
 
         slbe = kvmppc_mmu_book3s_64_find_slbe(vcpu_book3s, eaddr);
         if (!slbe)
@@ -445,6 +461,7 @@ static int kvmppc_mmu_book3s_64_esid_to_vsid(struct kvm_vcpu *vcpu, ulong esid,
         ulong ea = esid << SID_SHIFT;
         struct kvmppc_slb *slb;
         u64 gvsid = esid;
+        ulong mp_ea = vcpu->arch.magic_page_ea;
 
         if (vcpu->arch.shared->msr & (MSR_DR|MSR_IR)) {
                 slb = kvmppc_mmu_book3s_64_find_slbe(to_book3s(vcpu), ea);
@@ -464,7 +481,7 @@ static int kvmppc_mmu_book3s_64_esid_to_vsid(struct kvm_vcpu *vcpu, ulong esid,
                 break;
         case MSR_DR|MSR_IR:
                 if (!slb)
-                        return -ENOENT;
+                        goto no_slb;
 
                 *vsid = gvsid;
                 break;
@@ -477,6 +494,17 @@ static int kvmppc_mmu_book3s_64_esid_to_vsid(struct kvm_vcpu *vcpu, ulong esid,
                 *vsid |= VSID_PR;
 
         return 0;
+
+no_slb:
+        /* Catch magic page case */
+        if (unlikely(mp_ea) &&
+            unlikely(esid == (mp_ea >> SID_SHIFT)) &&
+            !(vcpu->arch.shared->msr & MSR_PR)) {
+                *vsid = VSID_REAL | esid;
+                return 0;
+        }
+
+        return -EINVAL;
 }
 
 static bool kvmppc_mmu_book3s_64_is_dcbz32(struct kvm_vcpu *vcpu)