[PATCH] KVM: MMU: Detect oom conditions and propagate error to userspace

Signed-off-by: Avi Kivity <avi@qumranet.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 21 insertions, 11 deletions

diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index e96362aa7947..7761089ef3bc 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -166,19 +166,20 @@ static int is_rmap_pte(u64 pte)
                 == (PT_WRITABLE_MASK | PT_PRESENT_MASK);
 }
 
-static void mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
-                                   size_t objsize, int min)
+static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
+                                  size_t objsize, int min)
 {
         void *obj;
 
         if (cache->nobjs >= min)
-                return;
+                return 0;
         while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
                 obj = kzalloc(objsize, GFP_NOWAIT);
                 if (!obj)
-                        BUG();
+                        return -ENOMEM;
                 cache->objects[cache->nobjs++] = obj;
         }
+        return 0;
 }
 
 static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
@@ -187,12 +188,18 @@ static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
                 kfree(mc->objects[--mc->nobjs]);
 }
 
-static void mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
+static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
 {
-        mmu_topup_memory_cache(&vcpu->mmu_pte_chain_cache,
-                               sizeof(struct kvm_pte_chain), 4);
-        mmu_topup_memory_cache(&vcpu->mmu_rmap_desc_cache,
-                               sizeof(struct kvm_rmap_desc), 1);
+        int r;
+
+        r = mmu_topup_memory_cache(&vcpu->mmu_pte_chain_cache,
+                                   sizeof(struct kvm_pte_chain), 4);
+        if (r)
+                goto out;
+        r = mmu_topup_memory_cache(&vcpu->mmu_rmap_desc_cache,
+                                   sizeof(struct kvm_rmap_desc), 1);
+out:
+        return r;
 }
 
 static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
@@ -824,8 +831,11 @@ static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
 {
         gpa_t addr = gva;
         hpa_t paddr;
+        int r;
 
-        mmu_topup_memory_caches(vcpu);
+        r = mmu_topup_memory_caches(vcpu);
+        if (r)
+                return r;
 
         ASSERT(vcpu);
         ASSERT(VALID_PAGE(vcpu->mmu.root_hpa));
@@ -1052,7 +1062,7 @@ int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
         r = init_kvm_mmu(vcpu);
         if (r < 0)
                 goto out;
-        mmu_topup_memory_caches(vcpu);
+        r = mmu_topup_memory_caches(vcpu);
 out:
         return r;
 }