[PATCH 6/7] kvm/ppc/e500: eliminate tlb_refs

Alexander Graf
2013-03-22T14:26:02Z

From: Scott Wood <scottwood@freescale.com>

Commit 523f0e5421c12610527c620b983b443f329e3a32 ("KVM: PPC: E500:
Explicitly mark shadow maps invalid") began using E500_TLB_VALID
for guest TLB1 entries, and skipping invalidations if it's not set.

However, when E500_TLB_VALID was set for such entries, it was on a
fake local ref, and so the invalidations never happen. gtlb_privs
is documented as being only for guest TLB0, though we already violate
that with E500_TLB_BITMAP.

Now that we have MMU notifiers, and thus don't need to actually
retain a reference to the mapped pages, get rid of tlb_refs, and
use gtlb_privs for E500_TLB_VALID in TLB1.

Since we can have more than one host TLB entry for a given tlbe_ref,
be careful not to clear existing flags that are relevant to other
host TLB entries when preparing a new host TLB entry.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
arch/powerpc/kvm/e500.h | 24 ++++--------
arch/powerpc/kvm/e500_mmu_host.c | 75 +++++++++++---------------------------
2 files changed, 30 insertions(+), 69 deletions(-)

diff --git a/arch/powerpc/kvm/e500.h b/arch/powerpc/kvm/e500.h
index 41cefd4..33db48a 100644
--- a/arch/powerpc/kvm/e500.h
+++ b/arch/powerpc/kvm/e500.h
@@ -26,17 +26,20 @@
#define E500_PID_NUM 3
#define E500_TLB_NUM 2

-#define E500_TLB_VALID 1
-#define E500_TLB_BITMAP 2
+/* entry is mapped somewhere in host TLB */
+#define E500_TLB_VALID (1 << 0)
+/* TLB1 entry is mapped by host TLB1, tracked by bitmaps */
+#define E500_TLB_BITMAP (1 << 1)
+/* TLB1 entry is mapped by host TLB0 */
#define E500_TLB_TLB0 (1 << 2)

struct tlbe_ref {
- pfn_t pfn;
- unsigned int flags; /* E500_TLB_* */
+ pfn_t pfn; /* valid only for TLB0, except briefly */
+ unsigned int flags; /* E500_TLB_* */
};

struct tlbe_priv {
- struct tlbe_ref ref; /* TLB0 only -- TLB1 uses tlb_refs */
+ struct tlbe_ref ref;
};

#ifdef CONFIG_KVM_E500V2
@@ -63,17 +66,6 @@ struct kvmppc_vcpu_e500 {

unsigned int gtlb_nv[E500_TLB_NUM];

- /*
- * information associated with each host TLB entry --
- * TLB1 only for now. If/when guest TLB1 entries can be
- * mapped with host TLB0, this will be used for that too.
- *
- * We don't want to use this for guest TLB0 because then we'd
- * have the overhead of doing the translation again even if
- * the entry is still in the guest TLB (e.g. we swapped out
- * and back, and our host TLB entries got evicted).
- */
- struct tlbe_ref *tlb_refs[E500_TLB_NUM];
unsigned int host_tlb1_nv;

u32 svr;
diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c
index 8e72b21..1c6a9d7 100644
--- a/arch/powerpc/kvm/e500_mmu_host.c
+++ b/arch/powerpc/kvm/e500_mmu_host.c
@@ -193,8 +193,11 @@ void inval_gtlbe_on_host(struct kvmppc_vcpu_e500 *vcpu_e500, int tlbsel,
struct tlbe_ref *ref = &vcpu_e500->gtlb_priv[tlbsel][esel].ref;

/* Don't bother with unmapped entries */
- if (!(ref->flags & E500_TLB_VALID))
- return;
+ if (!(ref->flags & E500_TLB_VALID)) {
+ WARN(ref->flags & (E500_TLB_BITMAP | E500_TLB_TLB0),
+ "%s: flags %x\n", __func__, ref->flags);
+ WARN_ON(tlbsel = 1 && vcpu_e500->g2h_tlb1_map[esel]);
+ }

if (tlbsel = 1 && ref->flags & E500_TLB_BITMAP) {
u64 tmp = vcpu_e500->g2h_tlb1_map[esel];
@@ -248,7 +251,7 @@ static inline void kvmppc_e500_ref_setup(struct tlbe_ref *ref,
pfn_t pfn)
{
ref->pfn = pfn;
- ref->flags = E500_TLB_VALID;
+ ref->flags |= E500_TLB_VALID;

if (tlbe_is_writable(gtlbe))
kvm_set_pfn_dirty(pfn);
@@ -257,6 +260,7 @@ static inline void kvmppc_e500_ref_setup(struct tlbe_ref *ref,
static inline void kvmppc_e500_ref_release(struct tlbe_ref *ref)
{
if (ref->flags & E500_TLB_VALID) {
+ /* FIXME: don't log bogus pfn for TLB1 */
trace_kvm_booke206_ref_release(ref->pfn, ref->flags);
ref->flags = 0;
}
@@ -274,36 +278,23 @@ static void clear_tlb1_bitmap(struct kvmppc_vcpu_e500 *vcpu_e500)

static void clear_tlb_privs(struct kvmppc_vcpu_e500 *vcpu_e500)
{
- int tlbsel = 0;
- int i;
-
- for (i = 0; i < vcpu_e500->gtlb_params[tlbsel].entries; i++) {
- struct tlbe_ref *ref - &vcpu_e500->gtlb_priv[tlbsel][i].ref;
- kvmppc_e500_ref_release(ref);
- }
-}
-
-static void clear_tlb_refs(struct kvmppc_vcpu_e500 *vcpu_e500)
-{
- int stlbsel = 1;
+ int tlbsel;
int i;

- kvmppc_e500_tlbil_all(vcpu_e500);
-
- for (i = 0; i < host_tlb_params[stlbsel].entries; i++) {
- struct tlbe_ref *ref - &vcpu_e500->tlb_refs[stlbsel][i];
- kvmppc_e500_ref_release(ref);
+ for (tlbsel = 0; tlbsel <= 1; tlbsel++) {
+ for (i = 0; i < vcpu_e500->gtlb_params[tlbsel].entries; i++) {
+ struct tlbe_ref *ref + &vcpu_e500->gtlb_priv[tlbsel][i].ref;
+ kvmppc_e500_ref_release(ref);
+ }
}
-
- clear_tlb_privs(vcpu_e500);
}

void kvmppc_core_flush_tlb(struct kvm_vcpu *vcpu)
{
struct kvmppc_vcpu_e500 *vcpu_e500 = to_e500(vcpu);
- clear_tlb_refs(vcpu_e500);
+ kvmppc_e500_tlbil_all(vcpu_e500);
+ clear_tlb_privs(vcpu_e500);
clear_tlb1_bitmap(vcpu_e500);
}

@@ -458,8 +449,6 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
gvaddr &= ~((tsize_pages << PAGE_SHIFT) - 1);
}

- /* Drop old ref and setup new one. */
- kvmppc_e500_ref_release(ref);
kvmppc_e500_ref_setup(ref, gtlbe, pfn);

kvmppc_e500_setup_stlbe(&vcpu_e500->vcpu, gtlbe, tsize,
@@ -512,10 +501,10 @@ static int kvmppc_e500_tlb1_map_tlb1(struct kvmppc_vcpu_e500 *vcpu_e500,
vcpu_e500->g2h_tlb1_map[idx] &= ~(1ULL << sesel);
}

- vcpu_e500->tlb_refs[1][sesel] = *ref;
vcpu_e500->gtlb_priv[1][esel].ref.flags |= E500_TLB_BITMAP;
vcpu_e500->g2h_tlb1_map[esel] |= (u64)1 << sesel;
vcpu_e500->h2g_tlb1_rmap[sesel] = esel + 1;
+ WARN_ON(!(ref->flags & E500_TLB_VALID));

return sesel;
}
@@ -527,13 +516,12 @@ static int kvmppc_e500_tlb1_map(struct kvmppc_vcpu_e500 *vcpu_e500,
u64 gvaddr, gfn_t gfn, struct kvm_book3e_206_tlb_entry *gtlbe,
struct kvm_book3e_206_tlb_entry *stlbe, int esel)
{
- struct tlbe_ref ref;
+ struct tlbe_ref *ref = &vcpu_e500->gtlb_priv[1][esel].ref;
int sesel;
int r;

- ref.flags = 0;
r = kvmppc_e500_shadow_map(vcpu_e500, gvaddr, gfn, gtlbe, 1, stlbe,
- &ref);
+ ref);
if (r)
return r;

@@ -545,7 +533,7 @@ static int kvmppc_e500_tlb1_map(struct kvmppc_vcpu_e500 *vcpu_e500,
}

/* Otherwise map into TLB1 */
- sesel = kvmppc_e500_tlb1_map_tlb1(vcpu_e500, &ref, esel);
+ sesel = kvmppc_e500_tlb1_map_tlb1(vcpu_e500, ref, esel);
write_stlbe(vcpu_e500, gtlbe, stlbe, 1, sesel);

return 0;
@@ -566,7 +554,7 @@ void kvmppc_mmu_map(struct kvm_vcpu *vcpu, u64 eaddr, gpa_t gpaddr,
case 0:
priv = &vcpu_e500->gtlb_priv[tlbsel][esel];

- /* Triggers after clear_tlb_refs or on initial mapping */
+ /* Triggers after clear_tlb_privs or on initial mapping */
if (!(priv->ref.flags & E500_TLB_VALID)) {
kvmppc_e500_tlb0_map(vcpu_e500, esel, &stlbe);
} else {
@@ -666,35 +654,16 @@ int e500_mmu_host_init(struct kvmppc_vcpu_e500 *vcpu_e500)
host_tlb_params[0].entries / host_tlb_params[0].ways;
host_tlb_params[1].sets = 1;

- vcpu_e500->tlb_refs[0] - kzalloc(sizeof(struct tlbe_ref) * host_tlb_params[0].entries,
- GFP_KERNEL);
- if (!vcpu_e500->tlb_refs[0])
- goto err;
-
- vcpu_e500->tlb_refs[1] - kzalloc(sizeof(struct tlbe_ref) * host_tlb_params[1].entries,
- GFP_KERNEL);
- if (!vcpu_e500->tlb_refs[1])
- goto err;
-
vcpu_e500->h2g_tlb1_rmap = kzalloc(sizeof(unsigned int) *
host_tlb_params[1].entries,
GFP_KERNEL);
if (!vcpu_e500->h2g_tlb1_rmap)
- goto err;
+ return -EINVAL;

return 0;
-
-err:
- kfree(vcpu_e500->tlb_refs[0]);
- kfree(vcpu_e500->tlb_refs[1]);
- return -EINVAL;
}

void e500_mmu_host_uninit(struct kvmppc_vcpu_e500 *vcpu_e500)
{
kfree(vcpu_e500->h2g_tlb1_rmap);
- kfree(vcpu_e500->tlb_refs[0]);
- kfree(vcpu_e500->tlb_refs[1]);
}
--
1.6.0.2