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KVM: Add instruction fetch checking when walking guest page table

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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>
This commit is contained in:
Yang, Wei Y 2011-06-03 11:14:16 +08:00 committed by Avi Kivity
parent 611c120f74
commit e57d4a356a
1 changed files with 8 additions and 1 deletions
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9
arch/x86/kvm/paging_tmpl.h
View file

@ -246,6 +246,12 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
gfn_t gfn;
u32 ac;
/* 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;
@ -305,7 +311,8 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
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;