KVM: MMU: Calculate correct base gfn for direct non-DIR level
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 <mtosatti@redhat.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index f46b6c9..c0350be 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2020,7 +2020,10 @@
}
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);