KVM: MMU: Fix oopses with SLUB
The kvm mmu uses page->private on shadow page tables; so does slub, and
an oops result. Fix by allocating regular pages for shadows instead of
using slub.
Tested-by: S.Çağlar Onur <caglar@pardus.org.tr>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index 48d28f1..d99d2fe 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -154,7 +154,6 @@
static struct kmem_cache *pte_chain_cache;
static struct kmem_cache *rmap_desc_cache;
-static struct kmem_cache *mmu_page_cache;
static struct kmem_cache *mmu_page_header_cache;
static int is_write_protection(struct kvm_vcpu *vcpu)
@@ -225,6 +224,29 @@
kfree(mc->objects[--mc->nobjs]);
}
+static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
+ int min, gfp_t gfp_flags)
+{
+ struct page *page;
+
+ if (cache->nobjs >= min)
+ return 0;
+ while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
+ page = alloc_page(gfp_flags);
+ if (!page)
+ return -ENOMEM;
+ set_page_private(page, 0);
+ cache->objects[cache->nobjs++] = page_address(page);
+ }
+ return 0;
+}
+
+static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
+{
+ while (mc->nobjs)
+ __free_page(mc->objects[--mc->nobjs]);
+}
+
static int __mmu_topup_memory_caches(struct kvm_vcpu *vcpu, gfp_t gfp_flags)
{
int r;
@@ -237,8 +259,7 @@
rmap_desc_cache, 1, gfp_flags);
if (r)
goto out;
- r = mmu_topup_memory_cache(&vcpu->mmu_page_cache,
- mmu_page_cache, 4, gfp_flags);
+ r = mmu_topup_memory_cache_page(&vcpu->mmu_page_cache, 4, gfp_flags);
if (r)
goto out;
r = mmu_topup_memory_cache(&vcpu->mmu_page_header_cache,
@@ -266,7 +287,7 @@
{
mmu_free_memory_cache(&vcpu->mmu_pte_chain_cache);
mmu_free_memory_cache(&vcpu->mmu_rmap_desc_cache);
- mmu_free_memory_cache(&vcpu->mmu_page_cache);
+ mmu_free_memory_cache_page(&vcpu->mmu_page_cache);
mmu_free_memory_cache(&vcpu->mmu_page_header_cache);
}
@@ -458,7 +479,7 @@
{
ASSERT(is_empty_shadow_page(page_head->spt));
list_del(&page_head->link);
- kfree(page_head->spt);
+ __free_page(virt_to_page(page_head->spt));
kfree(page_head);
++kvm->n_free_mmu_pages;
}
@@ -1301,8 +1322,6 @@
kmem_cache_destroy(pte_chain_cache);
if (rmap_desc_cache)
kmem_cache_destroy(rmap_desc_cache);
- if (mmu_page_cache)
- kmem_cache_destroy(mmu_page_cache);
if (mmu_page_header_cache)
kmem_cache_destroy(mmu_page_header_cache);
}
@@ -1320,12 +1339,6 @@
if (!rmap_desc_cache)
goto nomem;
- mmu_page_cache = kmem_cache_create("kvm_mmu_page",
- PAGE_SIZE,
- PAGE_SIZE, 0, NULL);
- if (!mmu_page_cache)
- goto nomem;
-
mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
sizeof(struct kvm_mmu_page),
0, 0, NULL);