KVM: PPC: Improve split mode

When in split mode, instruction relocation and data relocation are not equal.

So far we implemented this mode by reserving a special pseudo-VSID for the
two cases and flushing all PTEs when going into split mode, which is slow.

Unfortunately 32bit Linux and Mac OS X use split mode extensively. So to not
slow down things too much, I came up with a different idea: Mark the split
mode with a bit in the VSID and then treat it like any other segment.

This means we can just flush the shadow segment cache, but keep the PTEs
intact. I verified that this works with ppc32 Linux and Mac OS X 10.4
guests and does speed them up.

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

4 files changed, 46 insertions, 39 deletions

diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index 5d3bd0cc4116..6f74d93725a0 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -100,11 +100,10 @@ struct kvmppc_vcpu_book3s {
 #define CONTEXT_GUEST           1
 #define CONTEXT_GUEST_END       2
 
-#define VSID_REAL_DR    0x7ffffffffff00000ULL
-#define VSID_REAL_IR    0x7fffffffffe00000ULL
-#define VSID_SPLIT_MASK 0x7fffffffffe00000ULL
-#define VSID_REAL       0x7fffffffffc00000ULL
-#define VSID_BAT        0x7fffffffffb00000ULL
+#define VSID_REAL       0x1fffffffffc00000ULL
+#define VSID_BAT        0x1fffffffffb00000ULL
+#define VSID_REAL_DR    0x2000000000000000ULL
+#define VSID_REAL_IR    0x4000000000000000ULL
 #define VSID_PR         0x8000000000000000ULL
 
 extern void kvmppc_mmu_pte_flush(struct kvm_vcpu *vcpu, ulong ea, ulong ea_mask);
diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
index f66de7e518f7..397701d39ae7 100644
--- a/arch/powerpc/kvm/book3s.c
+++ b/arch/powerpc/kvm/book3s.c
@@ -148,16 +148,8 @@ void kvmppc_set_msr(struct kvm_vcpu *vcpu, u64 msr)
                 }
         }
 
-        if (((vcpu->arch.msr & (MSR_IR|MSR_DR)) != (old_msr & (MSR_IR|MSR_DR))) ||
-            (vcpu->arch.msr & MSR_PR) != (old_msr & MSR_PR)) {
-                bool dr = (vcpu->arch.msr & MSR_DR) ? true : false;
-                bool ir = (vcpu->arch.msr & MSR_IR) ? true : false;
-
-                /* Flush split mode PTEs */
-                if (dr != ir)
-                        kvmppc_mmu_pte_vflush(vcpu, VSID_SPLIT_MASK,
-                                              VSID_SPLIT_MASK);
-
+        if ((vcpu->arch.msr & (MSR_PR|MSR_IR|MSR_DR)) !=
+                   (old_msr & (MSR_PR|MSR_IR|MSR_DR))) {
                 kvmppc_mmu_flush_segments(vcpu);
                 kvmppc_mmu_map_segment(vcpu, kvmppc_get_pc(vcpu));
         }
@@ -535,6 +527,7 @@ int kvmppc_handle_pagefault(struct kvm_run *run, struct kvm_vcpu *vcpu,
         bool is_mmio = false;
         bool dr = (vcpu->arch.msr & MSR_DR) ? true : false;
         bool ir = (vcpu->arch.msr & MSR_IR) ? true : false;
+        u64 vsid;
 
         relocated = data ? dr : ir;
 
@@ -552,13 +545,20 @@ int kvmppc_handle_pagefault(struct kvm_run *run, struct kvm_vcpu *vcpu,
 
         switch (vcpu->arch.msr & (MSR_DR|MSR_IR)) {
         case 0:
-                pte.vpage |= VSID_REAL;
+                pte.vpage |= ((u64)VSID_REAL << (SID_SHIFT - 12));
                 break;
         case MSR_DR:
-                pte.vpage |= VSID_REAL_DR;
-                break;
         case MSR_IR:
-                pte.vpage |= VSID_REAL_IR;
+                vcpu->arch.mmu.esid_to_vsid(vcpu, eaddr >> SID_SHIFT, &vsid);
+
+                if ((vcpu->arch.msr & (MSR_DR|MSR_IR)) == MSR_DR)
+                        pte.vpage |= ((u64)VSID_REAL_DR << (SID_SHIFT - 12));
+                else
+                        pte.vpage |= ((u64)VSID_REAL_IR << (SID_SHIFT - 12));
+                pte.vpage |= vsid;
+
+                if (vsid == -1)
+                        page_found = -EINVAL;
                 break;
         }
 
diff --git a/arch/powerpc/kvm/book3s_32_mmu.c b/arch/powerpc/kvm/book3s_32_mmu.c
index 33186b745c90..0b10503c8a4a 100644
--- a/arch/powerpc/kvm/book3s_32_mmu.c
+++ b/arch/powerpc/kvm/book3s_32_mmu.c
@@ -330,30 +330,35 @@ static void kvmppc_mmu_book3s_32_tlbie(struct kvm_vcpu *vcpu, ulong ea, bool lar
 static int kvmppc_mmu_book3s_32_esid_to_vsid(struct kvm_vcpu *vcpu, ulong esid,
                                              u64 *vsid)
 {
+        ulong ea = esid << SID_SHIFT;
+        struct kvmppc_sr *sr;
+        u64 gvsid = esid;
+
+        if (vcpu->arch.msr & (MSR_DR|MSR_IR)) {
+                sr = find_sr(to_book3s(vcpu), ea);
+                if (sr->valid)
+                        gvsid = sr->vsid;
+        }
+
         /* In case we only have one of MSR_IR or MSR_DR set, let's put
            that in the real-mode context (and hope RM doesn't access
            high memory) */
         switch (vcpu->arch.msr & (MSR_DR|MSR_IR)) {
         case 0:
-                *vsid = (VSID_REAL >> 16) | esid;
+                *vsid = VSID_REAL | esid;
                 break;
         case MSR_IR:
-                *vsid = (VSID_REAL_IR >> 16) | esid;
+                *vsid = VSID_REAL_IR | gvsid;
                 break;
         case MSR_DR:
-                *vsid = (VSID_REAL_DR >> 16) | esid;
+                *vsid = VSID_REAL_DR | gvsid;
                 break;
         case MSR_DR|MSR_IR:
-        {
-                ulong ea = esid << SID_SHIFT;
-                struct kvmppc_sr *sr = find_sr(to_book3s(vcpu), ea);
-
                 if (!sr->valid)
                         return -1;
 
                 *vsid = sr->vsid;
                 break;
-        }
         default:
                 BUG();
         }
diff --git a/arch/powerpc/kvm/book3s_64_mmu.c b/arch/powerpc/kvm/book3s_64_mmu.c
index a9241e90a68b..612de6e4d74b 100644
--- a/arch/powerpc/kvm/book3s_64_mmu.c
+++ b/arch/powerpc/kvm/book3s_64_mmu.c
@@ -442,29 +442,32 @@ static void kvmppc_mmu_book3s_64_tlbie(struct kvm_vcpu *vcpu, ulong va,
 static int kvmppc_mmu_book3s_64_esid_to_vsid(struct kvm_vcpu *vcpu, ulong esid,
                                              u64 *vsid)
 {
+        ulong ea = esid << SID_SHIFT;
+        struct kvmppc_slb *slb;
+        u64 gvsid = esid;
+
+        if (vcpu->arch.msr & (MSR_DR|MSR_IR)) {
+                slb = kvmppc_mmu_book3s_64_find_slbe(to_book3s(vcpu), ea);
+                if (slb)
+                        gvsid = slb->vsid;
+        }
+
         switch (vcpu->arch.msr & (MSR_DR|MSR_IR)) {
         case 0:
-                *vsid = (VSID_REAL >> 16) | esid;
+                *vsid = VSID_REAL | esid;
                 break;
         case MSR_IR:
-                *vsid = (VSID_REAL_IR >> 16) | esid;
+                *vsid = VSID_REAL_IR | gvsid;
                 break;
         case MSR_DR:
-                *vsid = (VSID_REAL_DR >> 16) | esid;
+                *vsid = VSID_REAL_DR | gvsid;
                 break;
         case MSR_DR|MSR_IR:
-        {
-                ulong ea;
-                struct kvmppc_slb *slb;
-                ea = esid << SID_SHIFT;
-                slb = kvmppc_mmu_book3s_64_find_slbe(to_book3s(vcpu), ea);
-                if (slb)
-                        *vsid = slb->vsid;
-                else
+                if (!slb)
                         return -ENOENT;
 
+                *vsid = gvsid;
                 break;
-        }
         default:
                 BUG();
                 break;