KVM: MMU: Fix rare oops on guest context switch
A guest context switch to an uncached cr3 can require allocation of
shadow pages, but we only recycle shadow pages in kvm_mmu_page_fault().
Move shadow page recycling to mmu_topup_memory_caches(), which is called
from both the page fault handler and from guest cr3 reload.
Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index 3ac9cbc..336be86 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -619,7 +619,7 @@
void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
const u8 *old, const u8 *new, int bytes);
int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva);
-void kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu);
+void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu);
int kvm_mmu_load(struct kvm_vcpu *vcpu);
void kvm_mmu_unload(struct kvm_vcpu *vcpu);
@@ -628,11 +628,15 @@
static inline int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
u32 error_code)
{
- if (unlikely(vcpu->kvm->n_free_mmu_pages < KVM_MIN_FREE_MMU_PAGES))
- kvm_mmu_free_some_pages(vcpu);
return vcpu->mmu.page_fault(vcpu, gva, error_code);
}
+static inline void kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
+{
+ if (unlikely(vcpu->kvm->n_free_mmu_pages < KVM_MIN_FREE_MMU_PAGES))
+ __kvm_mmu_free_some_pages(vcpu);
+}
+
static inline int kvm_mmu_reload(struct kvm_vcpu *vcpu)
{
if (likely(vcpu->mmu.root_hpa != INVALID_PAGE))