From: Lai Jiangshan <[email protected]>

In Document/kvm/mmu.txt:
  gfn:
    Either the guest page table containing the translations shadowed by this
    page, or the base page frame for linear translations. See role.direct.

But in __direct_map(), the base gfn calculation is incorrect,
it does not calculate correctly when level=3 or 4.

Fix by using PT64_LVL_ADDR_MASK() which accounts for all levels correctly.

Reported-by: Marcelo Tosatti <[email protected]>
Signed-off-by: Lai Jiangshan <[email protected]>
Signed-off-by: Avi Kivity <[email protected]>

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 8374a22..d92984d 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2012,7 +2012,10 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, 
int write,
                }
 
                if (*iterator.sptep == shadow_trap_nonpresent_pte) {
-                       pseudo_gfn = (iterator.addr & PT64_DIR_BASE_ADDR_MASK) 
>> PAGE_SHIFT;
+                       u64 base_addr = iterator.addr;
+
+                       base_addr &= PT64_LVL_ADDR_MASK(iterator.level);
+                       pseudo_gfn = base_addr >> PAGE_SHIFT;
                        sp = kvm_mmu_get_page(vcpu, pseudo_gfn, iterator.addr,
                                              iterator.level - 1,
                                              1, ACC_ALL, iterator.sptep);
--
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