kvm/ppc/e500: eliminate tlb_refs

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>

2 files changed, 30 insertions, 69 deletions

diff --git a/arch/powerpc/kvm/e500.h b/arch/powerpc/kvm/e500.h
index 41cefd43655f..33db48a8ce24 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 8e72b2124f63..1c6a9d729df4 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]);
 }