[PATCH] KVM: MMU: oom handling
When beginning to process a page fault, make sure we have enough shadow pages
available to service the fault. If not, free some pages.
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>
diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index d788866..e4a20a4 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -310,6 +310,7 @@
list_del(&page_head->link);
page_head->page_hpa = page_hpa;
list_add(&page_head->link, &vcpu->free_pages);
+ ++vcpu->kvm->n_free_mmu_pages;
}
static int is_empty_shadow_page(hpa_t page_hpa)
@@ -344,6 +345,7 @@
page->global = 1;
page->multimapped = 0;
page->parent_pte = parent_pte;
+ --vcpu->kvm->n_free_mmu_pages;
return page;
}
@@ -544,8 +546,7 @@
}
kvm_mmu_page_unlink_children(vcpu, page);
hlist_del(&page->hash_link);
- list_del(&page->link);
- list_add(&page->link, &vcpu->free_pages);
+ kvm_mmu_free_page(vcpu, page->page_hpa);
}
static int kvm_mmu_unprotect_page(struct kvm_vcpu *vcpu, gfn_t gfn)
@@ -743,18 +744,6 @@
vcpu->mmu.root_hpa = __pa(vcpu->mmu.pae_root);
}
-static void nonpaging_flush(struct kvm_vcpu *vcpu)
-{
- hpa_t root = vcpu->mmu.root_hpa;
-
- ++kvm_stat.tlb_flush;
- pgprintk("nonpaging_flush\n");
- mmu_free_roots(vcpu);
- mmu_alloc_roots(vcpu);
- kvm_arch_ops->set_cr3(vcpu, root);
- kvm_arch_ops->tlb_flush(vcpu);
-}
-
static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr)
{
return vaddr;
@@ -763,28 +752,19 @@
static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
u32 error_code)
{
- int ret;
gpa_t addr = gva;
+ hpa_t paddr;
ASSERT(vcpu);
ASSERT(VALID_PAGE(vcpu->mmu.root_hpa));
- for (;;) {
- hpa_t paddr;
- paddr = gpa_to_hpa(vcpu , addr & PT64_BASE_ADDR_MASK);
+ paddr = gpa_to_hpa(vcpu , addr & PT64_BASE_ADDR_MASK);
- if (is_error_hpa(paddr))
- return 1;
+ if (is_error_hpa(paddr))
+ return 1;
- ret = nonpaging_map(vcpu, addr & PAGE_MASK, paddr);
- if (ret) {
- nonpaging_flush(vcpu);
- continue;
- }
- break;
- }
- return ret;
+ return nonpaging_map(vcpu, addr & PAGE_MASK, paddr);
}
static void nonpaging_inval_page(struct kvm_vcpu *vcpu, gva_t addr)
@@ -1093,6 +1073,18 @@
return kvm_mmu_unprotect_page(vcpu, gpa >> PAGE_SHIFT);
}
+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;
+
+ page = container_of(vcpu->kvm->active_mmu_pages.prev,
+ struct kvm_mmu_page, link);
+ kvm_mmu_zap_page(vcpu, page);
+ }
+}
+EXPORT_SYMBOL_GPL(kvm_mmu_free_some_pages);
+
static void free_mmu_pages(struct kvm_vcpu *vcpu)
{
while (!list_empty(&vcpu->free_pages)) {
@@ -1124,6 +1116,7 @@
page_header->page_hpa = (hpa_t)page_to_pfn(page) << PAGE_SHIFT;
memset(__va(page_header->page_hpa), 0, PAGE_SIZE);
list_add(&page_header->link, &vcpu->free_pages);
+ ++vcpu->kvm->n_free_mmu_pages;
}
/*