KVM: Fix vcpu freeing for guest smp
A vcpu can pin up to four mmu shadow pages, which means the freeing
loop will never terminate. Fix by first unpinning shadow pages on
all vcpus, then freeing shadow pages.
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 3c3231d..3ff8ee5 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -381,6 +381,16 @@
}
}
+static void kvm_unload_vcpu_mmu(struct kvm_vcpu *vcpu)
+{
+ if (!vcpu->vmcs)
+ return;
+
+ vcpu_load(vcpu);
+ kvm_mmu_unload(vcpu);
+ vcpu_put(vcpu);
+}
+
static void kvm_free_vcpu(struct kvm_vcpu *vcpu)
{
if (!vcpu->vmcs)
@@ -401,6 +411,11 @@
{
unsigned int i;
+ /*
+ * Unpin any mmu pages first.
+ */
+ for (i = 0; i < KVM_MAX_VCPUS; ++i)
+ kvm_unload_vcpu_mmu(&kvm->vcpus[i]);
for (i = 0; i < KVM_MAX_VCPUS; ++i)
kvm_free_vcpu(&kvm->vcpus[i]);
}
diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index 5915d7a..d4de988 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -838,11 +838,12 @@
int i;
struct kvm_mmu_page *page;
+ if (!VALID_PAGE(vcpu->mmu.root_hpa))
+ return;
#ifdef CONFIG_X86_64
if (vcpu->mmu.shadow_root_level == PT64_ROOT_LEVEL) {
hpa_t root = vcpu->mmu.root_hpa;
- ASSERT(VALID_PAGE(root));
page = page_header(root);
--page->root_count;
vcpu->mmu.root_hpa = INVALID_PAGE;
@@ -853,7 +854,6 @@
hpa_t root = vcpu->mmu.pae_root[i];
if (root) {
- ASSERT(VALID_PAGE(root));
root &= PT64_BASE_ADDR_MASK;
page = page_header(root);
--page->root_count;