diff options
Diffstat (limited to 'kernel/Documentation/virtual/kvm/mmu.txt')
| -rw-r--r-- | kernel/Documentation/virtual/kvm/mmu.txt | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/kernel/Documentation/virtual/kvm/mmu.txt b/kernel/Documentation/virtual/kvm/mmu.txt index c59bd9bc4..b653641d4 100644 --- a/kernel/Documentation/virtual/kvm/mmu.txt +++ b/kernel/Documentation/virtual/kvm/mmu.txt @@ -173,6 +173,12 @@ Shadow pages contain the following information: Contains the value of cr4.smap && !cr0.wp for which the page is valid (pages for which this is true are different from other pages; see the treatment of cr0.wp=0 below). + role.smm: + Is 1 if the page is valid in system management mode. This field + determines which of the kvm_memslots array was used to build this + shadow page; it is also used to go back from a struct kvm_mmu_page + to a memslot, through the kvm_memslots_for_spte_role macro and + __gfn_to_memslot. gfn: Either the guest page table containing the translations shadowed by this page, or the base page frame for linear translations. See role.direct. @@ -352,7 +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, |