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/mmu.c b/drivers/kvm/mmu.c
index 1a87ba9..23965aa 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -273,12 +273,14 @@
int r;
r = __mmu_topup_memory_caches(vcpu, GFP_NOWAIT);
+ kvm_mmu_free_some_pages(vcpu);
if (r < 0) {
spin_unlock(&vcpu->kvm->lock);
kvm_arch_ops->vcpu_put(vcpu);
r = __mmu_topup_memory_caches(vcpu, GFP_KERNEL);
kvm_arch_ops->vcpu_load(vcpu);
spin_lock(&vcpu->kvm->lock);
+ kvm_mmu_free_some_pages(vcpu);
}
return r;
}
@@ -1208,7 +1210,7 @@
return kvm_mmu_unprotect_page(vcpu, gpa >> PAGE_SHIFT);
}
-void kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
+void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
{
while (vcpu->kvm->n_free_mmu_pages < KVM_REFILL_PAGES) {
struct kvm_mmu_page *page;
@@ -1218,7 +1220,6 @@
kvm_mmu_zap_page(vcpu->kvm, page);
}
}
-EXPORT_SYMBOL_GPL(kvm_mmu_free_some_pages);
static void free_mmu_pages(struct kvm_vcpu *vcpu)
{