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Commit 8b6db3bc authored by Alexander Graf's avatar Alexander Graf Committed by Avi Kivity
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KVM: PPC: Implement correct SID mapping on Book3s_32 



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: default avatarAlexander Graf <agraf@suse.de>
parent ad087376

arch/powerpc/include/asm/kvm_book3s.h

+13 −2
Original line number Diff line number Diff line
@@ -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 */

};

arch/powerpc/kvm/book3s_32_mmu_host.c

+31 −26
Original line number Diff line number Diff line
@@ -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;



	for (i = 0; i < SID_CONTEXTS; i++) {

		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. */

			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;

}

arch/powerpc/kvm/book3s_64_mmu_host.c

+4 −4
Original line number Diff line number Diff line
@@ -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);