KVM: MMU: Make gfn_to_page() always safe
In case the page is not present in the guest memory map, return a dummy
page the guest can scribble on.
This simplifies error checking in its users.
Signed-off-by: Izik Eidus <izike@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index bbf5eb4..2ad14fb 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -850,23 +850,17 @@
__set_bit(slot, &page_head->slot_bitmap);
}
-hpa_t safe_gpa_to_hpa(struct kvm *kvm, gpa_t gpa)
-{
- hpa_t hpa = gpa_to_hpa(kvm, gpa);
-
- return is_error_hpa(hpa) ? bad_page_address | (gpa & ~PAGE_MASK): hpa;
-}
-
hpa_t gpa_to_hpa(struct kvm *kvm, gpa_t gpa)
{
struct page *page;
+ hpa_t hpa;
ASSERT((gpa & HPA_ERR_MASK) == 0);
page = gfn_to_page(kvm, gpa >> PAGE_SHIFT);
- if (!page)
- return gpa | HPA_ERR_MASK;
- return ((hpa_t)page_to_pfn(page) << PAGE_SHIFT)
- | (gpa & (PAGE_SIZE-1));
+ hpa = ((hpa_t)page_to_pfn(page) << PAGE_SHIFT) | (gpa & (PAGE_SIZE-1));
+ if (is_error_page(page))
+ return hpa | HPA_ERR_MASK;
+ return hpa;
}
hpa_t gva_to_hpa(struct kvm_vcpu *vcpu, gva_t gva)