KVM: PPC: Book3S PR: Use SLB entry 0

We didn't make use of SLB entry 0 because ... of no good reason. SLB entry 0
will always be used by the Linux linear SLB entry, so the fact that slbia
does not invalidate it doesn't matter as we overwrite SLB 0 on exit anyway.

Just enable use of SLB entry 0 for our shadow SLB code.

Signed-off-by: Alexander Graf <agraf@suse.de>

2 files changed, 6 insertions, 8 deletions

diff --git a/arch/powerpc/kvm/book3s_64_mmu_host.c b/arch/powerpc/kvm/book3s_64_mmu_host.c
index e2efb85c65a3..0ac98392f363 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_host.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_host.c
@@ -271,11 +271,8 @@ static int kvmppc_mmu_next_segment(struct kvm_vcpu *vcpu, ulong esid)
         int found_inval = -1;
         int r;
 
-        if (!svcpu->slb_max)
-                svcpu->slb_max = 1;
-
         /* Are we overwriting? */
-        for (i = 1; i < svcpu->slb_max; i++) {
+        for (i = 0; i < svcpu->slb_max; i++) {
                 if (!(svcpu->slb[i].esid & SLB_ESID_V))
                         found_inval = i;
                 else if ((svcpu->slb[i].esid & ESID_MASK) == esid) {
@@ -285,7 +282,7 @@ static int kvmppc_mmu_next_segment(struct kvm_vcpu *vcpu, ulong esid)
         }
 
         /* Found a spare entry that was invalidated before */
-        if (found_inval > 0) {
+        if (found_inval >= 0) {
                 r = found_inval;
                 goto out;
         }
@@ -359,7 +356,7 @@ void kvmppc_mmu_flush_segment(struct kvm_vcpu *vcpu, ulong ea, ulong seg_size)
         ulong seg_mask = -seg_size;
         int i;
 
-        for (i = 1; i < svcpu->slb_max; i++) {
+        for (i = 0; i < svcpu->slb_max; i++) {
                 if ((svcpu->slb[i].esid & SLB_ESID_V) &&
                     (svcpu->slb[i].esid & seg_mask) == ea) {
                         /* Invalidate this entry */
@@ -373,7 +370,7 @@ void kvmppc_mmu_flush_segment(struct kvm_vcpu *vcpu, ulong ea, ulong seg_size)
 void kvmppc_mmu_flush_segments(struct kvm_vcpu *vcpu)
 {
         struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
-        svcpu->slb_max = 1;
+        svcpu->slb_max = 0;
         svcpu->slb[0].esid = 0;
         svcpu_put(svcpu);
 }
diff --git a/arch/powerpc/kvm/book3s_64_slb.S b/arch/powerpc/kvm/book3s_64_slb.S
index 596140e5c889..84c52c6b5837 100644
--- a/arch/powerpc/kvm/book3s_64_slb.S
+++ b/arch/powerpc/kvm/book3s_64_slb.S
@@ -138,7 +138,8 @@ slb_do_enter:
 
         /* Restore bolted entries from the shadow and fix it along the way */
 
-        /* We don't store anything in entry 0, so we don't need to take care of it */
+        li      r0, r0
+        slbmte  r0, r0
         slbia
         isync