diff options
Diffstat (limited to 'Documentation/virtual/kvm/mmu.txt')
| -rw-r--r-- | Documentation/virtual/kvm/mmu.txt | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/Documentation/virtual/kvm/mmu.txt b/Documentation/virtual/kvm/mmu.txt index daf9c0f742d2..c81731096a43 100644 --- a/Documentation/virtual/kvm/mmu.txt +++ b/Documentation/virtual/kvm/mmu.txt | |||
| @@ -358,7 +358,8 @@ In the first case there are two additional complications: | |||
| 358 | - if CR4.SMEP is enabled: since we've turned the page into a kernel page, | 358 | - if CR4.SMEP is enabled: since we've turned the page into a kernel page, |
| 359 | the kernel may now execute it. We handle this by also setting spte.nx. | 359 | the kernel may now execute it. We handle this by also setting spte.nx. |
| 360 | If we get a user fetch or read fault, we'll change spte.u=1 and | 360 | If we get a user fetch or read fault, we'll change spte.u=1 and |
| 361 | spte.nx=gpte.nx back. | 361 | spte.nx=gpte.nx back. For this to work, KVM forces EFER.NX to 1 when |
| 362 | shadow paging is in use. | ||
| 362 | - if CR4.SMAP is disabled: since the page has been changed to a kernel | 363 | - if CR4.SMAP is disabled: since the page has been changed to a kernel |
| 363 | page, it can not be reused when CR4.SMAP is enabled. We set | 364 | page, it can not be reused when CR4.SMAP is enabled. We set |
| 364 | CR4.SMAP && !CR0.WP into shadow page's role to avoid this case. Note, | 365 | CR4.SMAP && !CR0.WP into shadow page's role to avoid this case. Note, |