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KVM: PPC: Implement correct SID mapping on Book3s_32

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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@suse.de>
This commit is contained in:
Alexander Graf 2010-08-15 08:04:24 +02:00 committed by Avi Kivity
parent ad0873763a
commit 8b6db3bc96
3 changed files with 48 additions and 32 deletions
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15
arch/powerpc/include/asm/kvm_book3s.h
View file

@ -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 */
};

57
arch/powerpc/kvm/book3s_32_mmu_host.c
View file

@ -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;
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 = CTX_TO_VSID(vcpu3s->context_id + 1) - 1;
vcpu3s->vsid_first = CTX_TO_VSID(vcpu3s->context_id);
/* Remember context id for this combination */
for (j = 0; j < 16; j++)
vcpu3s->vsid_pool[(i * 16) + j] = CTX_TO_VSID(err, j);
}
#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. */
vcpu3s->vsid_max |= 0x00800000;
vcpu3s->vsid_first |= 0x00800000;
#endif
BUG_ON(vcpu3s->vsid_max < vcpu3s->vsid_first);
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;
}

8
arch/powerpc/kvm/book3s_64_mmu_host.c
View file

@ -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);