This patch adds instruction fetch checking when walking guest page table,
to implement SMEP when emulating instead of executing natively.
Signed-off-by: Yang, Wei <wei.y.yang@intel.com>
Signed-off-by: Shan, Haitao <haitao.shan@intel.com>
Signed-off-by: Li, Xin <xin.li@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
+ /* check if the kernel is fetching from user page */
+ if (unlikely(pte_access & PT_USER_MASK) &&
+ kvm_read_cr4_bits(vcpu, X86_CR4_SMEP))
+ if (fetch_fault && !user_fault)
+ eperm = true;
+
gfn = gpte_to_gfn_lvl(pte, lvl);
gfn += (addr & PT_LVL_OFFSET_MASK(lvl)) >> PAGE_SHIFT;
gfn = gpte_to_gfn_lvl(pte, lvl);
gfn += (addr & PT_LVL_OFFSET_MASK(lvl)) >> PAGE_SHIFT;
walker->fault.error_code |= write_fault | user_fault;
walker->fault.error_code |= write_fault | user_fault;
- if (fetch_fault && mmu->nx)
+ if (fetch_fault && (mmu->nx ||
+ kvm_read_cr4_bits(vcpu, X86_CR4_SMEP)))
walker->fault.error_code |= PFERR_FETCH_MASK;
if (rsvd_fault)
walker->fault.error_code |= PFERR_RSVD_MASK;
walker->fault.error_code |= PFERR_FETCH_MASK;
if (rsvd_fault)
walker->fault.error_code |= PFERR_RSVD_MASK;