diff options
author | Avi Kivity <avi@redhat.com> | 2010-07-13 14:27:07 +0300 |
---|---|---|
committer | Avi Kivity <avi@redhat.com> | 2010-08-02 06:40:43 +0300 |
commit | a357bd229cdaf37a41798d238ab50b34c71dd0d6 (patch) | |
tree | 0a2801b53c7df2c8494bc5c572574cb29ad4aeee /arch/x86 | |
parent | a3aa51cfaafe9179add88db20506ccb07e030b47 (diff) | |
download | op-kernel-dev-a357bd229cdaf37a41798d238ab50b34c71dd0d6.zip op-kernel-dev-a357bd229cdaf37a41798d238ab50b34c71dd0d6.tar.gz |
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')
-rw-r--r-- | arch/x86/kvm/mmu.c | 23 | ||||
-rw-r--r-- | arch/x86/kvm/paging_tmpl.h | 27 |
2 files changed, 29 insertions, 21 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index b75d6cb..36c62f3 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) } } +static void validate_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep, + unsigned direct_access) +{ + if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep)) { + struct kvm_mmu_page *child; + + /* + * For the direct sp, if the guest pte's dirty bit + * changed form clean to dirty, it will corrupt the + * sp's access: allow writable in the read-only sp, + * so we should update the spte at this point to get + * a new sp with the correct access. + */ + child = page_header(*sptep & PT64_BASE_ADDR_MASK); + if (child->role.access == direct_access) + return; + + mmu_page_remove_parent_pte(child, sptep); + __set_spte(sptep, shadow_trap_nonpresent_pte); + kvm_flush_remote_tlbs(vcpu->kvm); + } +} + static void kvm_mmu_page_unlink_children(struct kvm *kvm, struct kvm_mmu_page *sp) { diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 0fb7068..0c7461d 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -338,30 +338,15 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, break; } - if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep)) { - struct kvm_mmu_page *child; - - if (level != gw->level) - continue; - - /* - * For the direct sp, if the guest pte's dirty bit - * changed form clean to dirty, it will corrupt the - * sp's access: allow writable in the read-only sp, - * so we should update the spte at this point to get - * a new sp with the correct access. - */ - child = page_header(*sptep & PT64_BASE_ADDR_MASK); - if (child->role.access == direct_access) - continue; - - mmu_page_remove_parent_pte(child, sptep); - __set_spte(sptep, shadow_trap_nonpresent_pte); - kvm_flush_remote_tlbs(vcpu->kvm); - } + if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep) + && level == gw->level) + validate_direct_spte(vcpu, sptep, direct_access); drop_large_spte(vcpu, sptep); + if (is_shadow_present_pte(*sptep)) + continue; + if (level <= gw->level) { direct = 1; access = direct_access; |