[PATCH 3/11] KVM: Fix gva_to_gpa()

Avi Kivity
2007-01-30T14:39:00Z

gva_to_gpa() needs to be updated to the new walk_addr() calling convention,
otherwise it may oops under some circumstances.

Use the opportunity to remove all the code duplication in gva_to_gpa(), which
essentially repeats the calculations in walk_addr().

Signed-off-by: Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>

Index: linux-2.6/drivers/kvm/paging_tmpl.h
===================================================================
--- linux-2.6.orig/drivers/kvm/paging_tmpl.h
+++ linux-2.6/drivers/kvm/paging_tmpl.h
@@ -443,31 +443,17 @@ static int FNAME(page_fault)(struct kvm_
static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t vaddr)
{
struct guest_walker walker;
- pt_element_t guest_pte;
- gpa_t gpa;
+ gpa_t gpa = UNMAPPED_GVA;
+ int r;

- FNAME(walk_addr)(&walker, vcpu, vaddr, 0, 0, 0);
- guest_pte = *walker.ptep;
- FNAME(release_walker)(&walker);
-
- if (!is_present_pte(guest_pte))
- return UNMAPPED_GVA;
-
- if (walker.level == PT_DIRECTORY_LEVEL) {
- ASSERT((guest_pte & PT_PAGE_SIZE_MASK));
- ASSERT(PTTYPE == 64 || is_pse(vcpu));
+ r = FNAME(walk_addr)(&walker, vcpu, vaddr, 0, 0, 0);

- gpa = (guest_pte & PT_DIR_BASE_ADDR_MASK) | (vaddr &
- (PT_LEVEL_MASK(PT_PAGE_TABLE_LEVEL) | ~PAGE_MASK));
-
- if (PTTYPE == 32 && is_cpuid_PSE36())
- gpa |= (guest_pte & PT32_DIR_PSE36_MASK) <<
- (32 - PT32_DIR_PSE36_SHIFT);
- } else {
- gpa = (guest_pte & PT_BASE_ADDR_MASK);
- gpa |= (vaddr & ~PAGE_MASK);
+ if (r) {
+ gpa = (gpa_t)walker.gfn << PAGE_SHIFT;
+ gpa |= vaddr & ~PAGE_MASK;
}

+ FNAME(release_walker)(&walker);
return gpa;
}