diff options
author | Avi Kivity <avi@redhat.com> | 2010-07-13 07:27:07 -0400 |
---|---|---|
committer | Avi Kivity <avi@redhat.com> | 2010-08-01 23:40:43 -0400 |
commit | a357bd229cdaf37a41798d238ab50b34c71dd0d6 (patch) | |
tree | 0a2801b53c7df2c8494bc5c572574cb29ad4aeee /arch/x86/kvm/mmu.c | |
parent | a3aa51cfaafe9179add88db20506ccb07e030b47 (diff) |
KVM: MMU: Add validate_direct_spte() helper
Add a helper to verify that a direct shadow page is valid wrt the required
access permissions; drop the page if it is not valid.
Reviewed-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch/x86/kvm/mmu.c')
-rw-r--r-- | arch/x86/kvm/mmu.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index b75d6cb44ab6..36c62f33513f 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c | |||
@@ -1500,6 +1500,29 @@ static void drop_large_spte(struct kvm_vcpu *vcpu, u64 *sptep) | |||
1500 | } | 1500 | } |
1501 | } | 1501 | } |
1502 | 1502 | ||
1503 | static void validate_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep, | ||
1504 | unsigned direct_access) | ||
1505 | { | ||
1506 | if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep)) { | ||
1507 | struct kvm_mmu_page *child; | ||
1508 | |||
1509 | /* | ||
1510 | * For the direct sp, if the guest pte's dirty bit | ||
1511 | * changed form clean to dirty, it will corrupt the | ||
1512 | * sp's access: allow writable in the read-only sp, | ||
1513 | * so we should update the spte at this point to get | ||
1514 | * a new sp with the correct access. | ||
1515 | */ | ||
1516 | child = page_header(*sptep & PT64_BASE_ADDR_MASK); | ||
1517 | if (child->role.access == direct_access) | ||
1518 | return; | ||
1519 | |||
1520 | mmu_page_remove_parent_pte(child, sptep); | ||
1521 | __set_spte(sptep, shadow_trap_nonpresent_pte); | ||
1522 | kvm_flush_remote_tlbs(vcpu->kvm); | ||
1523 | } | ||
1524 | } | ||
1525 | |||
1503 | static void kvm_mmu_page_unlink_children(struct kvm *kvm, | 1526 | static void kvm_mmu_page_unlink_children(struct kvm *kvm, |
1504 | struct kvm_mmu_page *sp) | 1527 | struct kvm_mmu_page *sp) |
1505 | { | 1528 | { |