KVM: PPC: E500: Propagate errors when shadow mapping

When shadow mapping a page, mapping this page can fail. In that case we
don't have a shadow map.

Take this case into account, otherwise we might end up writing bogus TLB
entries into the host TLB.

While at it, also move the write_stlbe() calls into the respective TLBn
handlers.

Signed-off-by: Alexander Graf <agraf@suse.de>

diff --git a/arch/powerpc/kvm/e500_tlb.c b/arch/powerpc/kvm/e500_tlb.c
index 8efb2acee2bfc8b09b6775a10bbd097428334b27..3777167e5f3125a7d70a7243d2d15f14d29274f3 100644 (file)
--- a/arch/powerpc/kvm/e500_tlb.c
+++ b/arch/powerpc/kvm/e500_tlb.c
@@ -432,7 +432,7 @@ static inline void kvmppc_e500_setup_stlbe(
 #endif
 }
 
-static inline void kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
+static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
        u64 gvaddr, gfn_t gfn, struct kvm_book3e_206_tlb_entry *gtlbe,
        int tlbsel, struct kvm_book3e_206_tlb_entry *stlbe,
        struct tlbe_ref *ref)
@@ -551,7 +551,7 @@ static inline void kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
                if (is_error_noslot_pfn(pfn)) {
                        printk(KERN_ERR "Couldn't get real page for gfn %lx!\n",
                                        (long)gfn);
-                       return;
+                       return -EINVAL;
                }
 
                /* Align guest and physical address to page map boundaries */
@@ -571,22 +571,33 @@ static inline void kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
 
        /* Drop refcount on page, so that mmu notifiers can clear it */
        kvm_release_pfn_clean(pfn);
+
+       return 0;
 }
 
 /* XXX only map the one-one case, for now use TLB0 */
-static void kvmppc_e500_tlb0_map(struct kvmppc_vcpu_e500 *vcpu_e500,
-                                int esel,
-                                struct kvm_book3e_206_tlb_entry *stlbe)
+static int kvmppc_e500_tlb0_map(struct kvmppc_vcpu_e500 *vcpu_e500,
+                               int esel,
+                               struct kvm_book3e_206_tlb_entry *stlbe)
 {
        struct kvm_book3e_206_tlb_entry *gtlbe;
        struct tlbe_ref *ref;
+       int stlbsel = 0;
+       int sesel = 0;
+       int r;
 
        gtlbe = get_entry(vcpu_e500, 0, esel);
        ref = &vcpu_e500->gtlb_priv[0][esel].ref;
 
-       kvmppc_e500_shadow_map(vcpu_e500, get_tlb_eaddr(gtlbe),
+       r = kvmppc_e500_shadow_map(vcpu_e500, get_tlb_eaddr(gtlbe),
                        get_tlb_raddr(gtlbe) >> PAGE_SHIFT,
                        gtlbe, 0, stlbe, ref);
+       if (r)
+               return r;
+
+       write_stlbe(vcpu_e500, gtlbe, stlbe, stlbsel, sesel);
+
+       return 0;
 }
 
 /* Caller must ensure that the specified guest TLB entry is safe to insert into
@@ -597,25 +608,32 @@ static int kvmppc_e500_tlb1_map(struct kvmppc_vcpu_e500 *vcpu_e500,
                struct kvm_book3e_206_tlb_entry *stlbe, int esel)
 {
        struct tlbe_ref *ref;
-       unsigned int victim;
+       unsigned int sesel;
+       int r;
+       int stlbsel = 1;
 
-       victim = vcpu_e500->host_tlb1_nv++;
+       sesel = vcpu_e500->host_tlb1_nv++;
 
        if (unlikely(vcpu_e500->host_tlb1_nv >= tlb1_max_shadow_size()))
                vcpu_e500->host_tlb1_nv = 0;
 
-       ref = &vcpu_e500->tlb_refs[1][victim];
-       kvmppc_e500_shadow_map(vcpu_e500, gvaddr, gfn, gtlbe, 1, stlbe, ref);
+       ref = &vcpu_e500->tlb_refs[1][sesel];
+       r = kvmppc_e500_shadow_map(vcpu_e500, gvaddr, gfn, gtlbe, 1, stlbe,
+                                  ref);
+       if (r)
+               return r;
 
-       vcpu_e500->g2h_tlb1_map[esel] |= (u64)1 << victim;
+       vcpu_e500->g2h_tlb1_map[esel] |= (u64)1 << sesel;
        vcpu_e500->gtlb_priv[1][esel].ref.flags |= E500_TLB_BITMAP;
-       if (vcpu_e500->h2g_tlb1_rmap[victim]) {
-               unsigned int idx = vcpu_e500->h2g_tlb1_rmap[victim];
-               vcpu_e500->g2h_tlb1_map[idx] &= ~(1ULL << victim);
+       if (vcpu_e500->h2g_tlb1_rmap[sesel]) {
+               unsigned int idx = vcpu_e500->h2g_tlb1_rmap[sesel];
+               vcpu_e500->g2h_tlb1_map[idx] &= ~(1ULL << sesel);
        }
-       vcpu_e500->h2g_tlb1_rmap[victim] = esel;
+       vcpu_e500->h2g_tlb1_rmap[sesel] = esel;
 
-       return victim;
+       write_stlbe(vcpu_e500, gtlbe, stlbe, stlbsel, sesel);
+
+       return 0;
 }
 
 static void kvmppc_recalc_tlb1map_range(struct kvmppc_vcpu_e500 *vcpu_e500)
@@ -1034,30 +1052,27 @@ void kvmppc_mmu_map(struct kvm_vcpu *vcpu, u64 eaddr, gpa_t gpaddr,
        struct kvm_book3e_206_tlb_entry *gtlbe, stlbe;
        int tlbsel = tlbsel_of(index);
        int esel = esel_of(index);
-       int stlbsel, sesel;
 
        gtlbe = get_entry(vcpu_e500, tlbsel, esel);
 
        switch (tlbsel) {
        case 0:
-               stlbsel = 0;
-               sesel = 0; /* unused */
                priv = &vcpu_e500->gtlb_priv[tlbsel][esel];
 
-               /* Only triggers after clear_tlb_refs */
-               if (unlikely(!(priv->ref.flags & E500_TLB_VALID)))
+               /* Triggers after clear_tlb_refs or on initial mapping */
+               if (!(priv->ref.flags & E500_TLB_VALID)) {
                        kvmppc_e500_tlb0_map(vcpu_e500, esel, &stlbe);
-               else
+               } else {
                        kvmppc_e500_setup_stlbe(vcpu, gtlbe, BOOK3E_PAGESZ_4K,
                                                &priv->ref, eaddr, &stlbe);
+                       write_stlbe(vcpu_e500, gtlbe, &stlbe, 0, 0);
+               }
                break;
 
        case 1: {
                gfn_t gfn = gpaddr >> PAGE_SHIFT;
-
-               stlbsel = 1;
-               sesel = kvmppc_e500_tlb1_map(vcpu_e500, eaddr, gfn,
-                                            gtlbe, &stlbe, esel);
+               kvmppc_e500_tlb1_map(vcpu_e500, eaddr, gfn, gtlbe, &stlbe,
+                                    esel);
                break;
        }
 
@@ -1065,8 +1080,6 @@ void kvmppc_mmu_map(struct kvm_vcpu *vcpu, u64 eaddr, gpa_t gpaddr,
                BUG();
                break;
        }
-
-       write_stlbe(vcpu_e500, gtlbe, &stlbe, stlbsel, sesel);
 }
 
 /************* MMU Notifiers *************/