diff options
| author | Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> | 2010-10-28 16:48:10 -0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-11-22 10:47:33 -0800 |
| commit | 31c6c80f10a4d09fba8ad8d4c57ac2eb2bd23335 (patch) | |
| tree | 23fff37dbe20f19e8cdc5c79eb7ac85028ab750a | |
| parent | 004ff730b84c2f35a69871fe3bcde07232ed8610 (diff) | |
KVM: MMU: fix direct sps access corrupted
commit 9e7b0e7fba45ca3c6357aeb7091ebc281f1de365 upstream.
If the mapping is writable but the dirty flag is not set, we will find
the read-only direct sp and setup the mapping, then if the write #PF
occur, we will mark this mapping writable in the read-only direct sp,
now, other real read-only mapping will happily write it without #PF.
It may hurt guest's COW
Fixed by re-install the mapping when write #PF occur.
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | arch/x86/kvm/paging_tmpl.h | 28 |
1 files changed, 26 insertions, 2 deletions
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 8faa821d1257..460acca9e09c 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -318,8 +318,32 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, break; } - if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep)) - continue; + if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep)) { + struct kvm_mmu_page *child; + unsigned direct_access; + + 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. + */ + direct_access = gw->pt_access & gw->pte_access; + if (!is_dirty_gpte(gw->ptes[gw->level - 1])) + direct_access &= ~ACC_WRITE_MASK; + + 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_large_pte(*sptep)) { rmap_remove(vcpu->kvm, sptep); |