Up until now we were doing segment mappings wrong on Book3s_32. For Book3s_64
we were using a trick where we know that a single mmu_context gives us 16 bits
of context ids.
The mm system on Book3s_32 instead uses a clever algorithm to distribute VSIDs
across the available range, so a context id really only gives us 16 available
VSIDs.
To keep at least a few guest processes in the SID shadow, let's map a number of
contexts that we can use as VSID pool. This makes the code be actually correct
and shouldn't hurt performance too much.
Signed-off-by: Alexander Graf <agraf@xxxxxxx>
---
arch/powerpc/include/asm/kvm_book3s.h | 15 +++++++-
arch/powerpc/kvm/book3s_32_mmu_host.c | 57 ++++++++++++++++++---------------
arch/powerpc/kvm/book3s_64_mmu_host.c | 8 ++--
3 files changed, 48 insertions(+), 32 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index be8aac2..d62e703 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -60,6 +60,13 @@ struct kvmppc_sid_map {
#define SID_MAP_NUM (1 << SID_MAP_BITS)
#define SID_MAP_MASK (SID_MAP_NUM - 1)
+#ifdef CONFIG_PPC_BOOK3S_64
+#define SID_CONTEXTS 1
+#else
+#define SID_CONTEXTS 128
+#define VSID_POOL_SIZE (SID_CONTEXTS * 16)
+#endif
+
struct kvmppc_vcpu_book3s {
struct kvm_vcpu vcpu;
struct kvmppc_book3s_shadow_vcpu *shadow_vcpu;
@@ -78,10 +85,14 @@ struct kvmppc_vcpu_book3s {
u64 sdr1;
u64 hior;
u64 msr_mask;
- u64 vsid_first;
u64 vsid_next;
+#ifdef CONFIG_PPC_BOOK3S_32
+ u32 vsid_pool[VSID_POOL_SIZE];
+#else
+ u64 vsid_first;
u64 vsid_max;
- int context_id;
+#endif
+ int context_id[SID_CONTEXTS];
ulong prog_flags; /* flags to inject when giving a 700 trap */
};
diff --git a/arch/powerpc/kvm/book3s_32_mmu_host.c b/arch/powerpc/kvm/book3s_32_mmu_host.c
index 57dddeb..9fecbfb 100644
--- a/arch/powerpc/kvm/book3s_32_mmu_host.c
+++ b/arch/powerpc/kvm/book3s_32_mmu_host.c
@@ -275,18 +275,15 @@ static struct kvmppc_sid_map *create_sid_map(struct kvm_vcpu *vcpu, u64 gvsid)
backwards_map = !backwards_map;
/* Uh-oh ... out of mappings. Let's flush! */
- if (vcpu_book3s->vsid_next >= vcpu_book3s->vsid_max) {
- vcpu_book3s->vsid_next = vcpu_book3s->vsid_first;
+ if (vcpu_book3s->vsid_next >= VSID_POOL_SIZE) {
+ vcpu_book3s->vsid_next = 0;
memset(vcpu_book3s->sid_map, 0,
sizeof(struct kvmppc_sid_map) * SID_MAP_NUM);
kvmppc_mmu_pte_flush(vcpu, 0, 0);
kvmppc_mmu_flush_segments(vcpu);
}
- map->host_vsid = vcpu_book3s->vsid_next;
-
- /* Would have to be 111 to be completely aligned with the rest of
- Linux, but that is just way too little space! */
- vcpu_book3s->vsid_next+=1;
+ map->host_vsid = vcpu_book3s->vsid_pool[vcpu_book3s->vsid_next];
+ vcpu_book3s->vsid_next++;
map->guest_vsid = gvsid;
map->valid = true;
@@ -333,40 +330,38 @@ void kvmppc_mmu_flush_segments(struct kvm_vcpu *vcpu)
void kvmppc_mmu_destroy(struct kvm_vcpu *vcpu)
{
+ int i;
+
kvmppc_mmu_hpte_destroy(vcpu);
preempt_disable();
- __destroy_context(to_book3s(vcpu)->context_id);
+ for (i = 0; i < SID_CONTEXTS; i++)
+ __destroy_context(to_book3s(vcpu)->context_id[i]);
preempt_enable();
}
/* From mm/mmu_context_hash32.c */
-#define CTX_TO_VSID(ctx) (((ctx) * (897 * 16)) & 0xffffff)
+#define CTX_TO_VSID(c, id) ((((c) * (897 * 16)) + (id * 0x111)) & 0xffffff)
int kvmppc_mmu_init(struct kvm_vcpu *vcpu)
{
struct kvmppc_vcpu_book3s *vcpu3s = to_book3s(vcpu);
int err;
ulong sdr1;
+ int i;
+ int j;
- err = __init_new_context();
- if (err < 0)
- return -1;
- vcpu3s->context_id = err;
-
- vcpu3s->vsid_max = CTX_TO_VSID(vcpu3s->context_id + 1) - 1;
- vcpu3s->vsid_first = CTX_TO_VSID(vcpu3s->context_id);
-
-#if 0 /* XXX still doesn't guarantee uniqueness */
- /* We could collide with the Linux vsid space because the vsid
- * wraps around at 24 bits. We're safe if we do our own space
- * though, so let's always set the highest bit. */
+ for (i = 0; i < SID_CONTEXTS; i++) {
+ err = __init_new_context();
+ if (err < 0)
+ goto init_fail;
+ vcpu3s->context_id[i] = err;
- vcpu3s->vsid_max |= 0x00800000;
- vcpu3s->vsid_first |= 0x00800000;
-#endif
- BUG_ON(vcpu3s->vsid_max < vcpu3s->vsid_first);
+ /* Remember context id for this combination */
+ for (j = 0; j < 16; j++)
+ vcpu3s->vsid_pool[(i * 16) + j] = CTX_TO_VSID(err, j);
+ }
- vcpu3s->vsid_next = vcpu3s->vsid_first;
+ vcpu3s->vsid_next = 0;
/* Remember where the HTAB is */
asm ( "mfsdr1 %0" : "=r"(sdr1) );
@@ -376,4 +371,14 @@ int kvmppc_mmu_init(struct kvm_vcpu *vcpu)
kvmppc_mmu_hpte_init(vcpu);
return 0;
+
+init_fail:
+ for (j = 0; j < i; j++) {
+ if (!vcpu3s->context_id[j])
+ continue;
+
+ __destroy_context(to_book3s(vcpu)->context_id[j]);
+ }
+
+ return -1;
}
diff --git a/arch/powerpc/kvm/book3s_64_mmu_host.c b/arch/powerpc/kvm/book3s_64_mmu_host.c
index 4040c8d..fa2f084 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_host.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_host.c
@@ -286,7 +286,7 @@ void kvmppc_mmu_flush_segments(struct kvm_vcpu *vcpu)
void kvmppc_mmu_destroy(struct kvm_vcpu *vcpu)
{
kvmppc_mmu_hpte_destroy(vcpu);
- __destroy_context(to_book3s(vcpu)->context_id);
+ __destroy_context(to_book3s(vcpu)->context_id[0]);
}
int kvmppc_mmu_init(struct kvm_vcpu *vcpu)
@@ -297,10 +297,10 @@ int kvmppc_mmu_init(struct kvm_vcpu *vcpu)
err = __init_new_context();
if (err < 0)
return -1;
- vcpu3s->context_id = err;
+ vcpu3s->context_id[0] = err;
- vcpu3s->vsid_max = ((vcpu3s->context_id + 1) << USER_ESID_BITS) - 1;
- vcpu3s->vsid_first = vcpu3s->context_id << USER_ESID_BITS;
+ vcpu3s->vsid_max = ((vcpu3s->context_id[0] + 1) << USER_ESID_BITS) - 1;
+ vcpu3s->vsid_first = vcpu3s->context_id[0] << USER_ESID_BITS;
vcpu3s->vsid_next = vcpu3s->vsid_first;
kvmppc_mmu_hpte_init(vcpu);
--
1.6.0.2
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