KVM: MMU: Introduce kvm_read_nested_guest_page()
This patch introduces the kvm_read_guest_page_x86 function
which reads from the physical memory of the guest. If the
guest is running in guest-mode itself with nested paging
enabled it will read from the guest's guest physical memory
instead.
The patch also changes changes the code to use this function
where it is necessary.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a2efb70..46843ed 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -392,6 +392,13 @@
}
EXPORT_SYMBOL_GPL(kvm_read_guest_page_mmu);
+int kvm_read_nested_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn,
+ void *data, int offset, int len, u32 access)
+{
+ return kvm_read_guest_page_mmu(vcpu, vcpu->arch.walk_mmu, gfn,
+ data, offset, len, access);
+}
+
/*
* Load the pae pdptrs. Return true is they are all valid.
*/
@@ -403,8 +410,9 @@
int ret;
u64 pdpte[ARRAY_SIZE(vcpu->arch.pdptrs)];
- ret = kvm_read_guest_page(vcpu->kvm, pdpt_gfn, pdpte,
- offset * sizeof(u64), sizeof(pdpte));
+ ret = kvm_read_nested_guest_page(vcpu, pdpt_gfn, pdpte,
+ offset * sizeof(u64), sizeof(pdpte),
+ PFERR_USER_MASK|PFERR_WRITE_MASK);
if (ret < 0) {
ret = 0;
goto out;
@@ -433,6 +441,8 @@
{
u64 pdpte[ARRAY_SIZE(vcpu->arch.pdptrs)];
bool changed = true;
+ int offset;
+ gfn_t gfn;
int r;
if (is_long_mode(vcpu) || !is_pae(vcpu))
@@ -442,7 +452,10 @@
(unsigned long *)&vcpu->arch.regs_avail))
return true;
- r = kvm_read_guest(vcpu->kvm, vcpu->arch.cr3 & ~31u, pdpte, sizeof(pdpte));
+ gfn = (vcpu->arch.cr3 & ~31u) >> PAGE_SHIFT;
+ offset = (vcpu->arch.cr3 & ~31u) & (PAGE_SIZE - 1);
+ r = kvm_read_nested_guest_page(vcpu, gfn, pdpte, offset, sizeof(pdpte),
+ PFERR_USER_MASK | PFERR_WRITE_MASK);
if (r < 0)
goto out;
changed = memcmp(pdpte, vcpu->arch.pdptrs, sizeof(pdpte)) != 0;