[PULL 40/41] KVM: PPC: Book3S PR: Use SLB entry 0

Alexander Graf
2014-05-30T12:43:08Z

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>
---
arch/powerpc/kvm/book3s_64_mmu_host.c | 11 ++++-------
arch/powerpc/kvm/book3s_64_slb.S | 3 ++-
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 e2efb85..0ac9839 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 596140e..84c52c6 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

--
1.8.1.4