diff options
Diffstat (limited to 'Documentation/virtual/kvm/mmu.txt')
| -rw-r--r-- | Documentation/virtual/kvm/mmu.txt | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/Documentation/virtual/kvm/mmu.txt b/Documentation/virtual/kvm/mmu.txt index 3a4d681c3..c81731096 100644 --- a/Documentation/virtual/kvm/mmu.txt +++ b/Documentation/virtual/kvm/mmu.txt @@ -203,10 +203,10 @@ Shadow pages contain the following information: page cannot be destroyed. See role.invalid. parent_ptes: The reverse mapping for the pte/ptes pointing at this page's spt. If - parent_ptes bit 0 is zero, only one spte points at this pages and + parent_ptes bit 0 is zero, only one spte points at this page and parent_ptes points at this single spte, otherwise, there exists multiple sptes pointing at this page and (parent_ptes & ~0x1) points at a data - structure with a list of parent_ptes. + structure with a list of parent sptes. unsync: If true, then the translations in this page may not match the guest's translation. This is equivalent to the state of the tlb when a pte is @@ -358,7 +358,8 @@ In the first case there are two additional complications: - if CR4.SMEP is enabled: since we've turned the page into a kernel page, the kernel may now execute it. We handle this by also setting spte.nx. If we get a user fetch or read fault, we'll change spte.u=1 and - spte.nx=gpte.nx back. + spte.nx=gpte.nx back. For this to work, KVM forces EFER.NX to 1 when + shadow paging is in use. - if CR4.SMAP is disabled: since the page has been changed to a kernel page, it can not be reused when CR4.SMAP is enabled. We set CR4.SMAP && !CR0.WP into shadow page's role to avoid this case. Note, |