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| author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-06-08 10:19:40 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-06-08 10:19:40 -0700 |
| commit | 987aec39a74373c55c3bedd5c3c83896d78fd0a2 (patch) | |
| tree | 66aba6d4f166f269be95fe4d267d57efe533aefd /Documentation/virtual/kvm | |
| parent | 303cda0ea7c1c33701812ccb80d37083a4093c7c (diff) | |
| parent | d4a4f75cd8f29cd9464a5a32e9224a91571d6649 (diff) | |
| download | linux-987aec39a74373c55c3bedd5c3c83896d78fd0a2.tar.gz | |
Merge 4.1-rc7 into driver-core-next
We want the fixes in this branch as well for testing and merge
resolution.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/virtual/kvm')
| -rw-r--r-- | Documentation/virtual/kvm/mmu.txt | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/Documentation/virtual/kvm/mmu.txt b/Documentation/virtual/kvm/mmu.txt index 53838d9c6295..c59bd9bc41ef 100644 --- a/Documentation/virtual/kvm/mmu.txt +++ b/Documentation/virtual/kvm/mmu.txt @@ -169,6 +169,10 @@ Shadow pages contain the following information: Contains the value of cr4.smep && !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.smap_andnot_wp: + 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). gfn: Either the guest page table containing the translations shadowed by this page, or the base page frame for linear translations. See role.direct. @@ -344,10 +348,16 @@ on fault type: (user write faults generate a #PF) -In the first case there is an additional complication 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. +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. +- 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, + here we do not care the case that CR4.SMAP is enabled since KVM will + directly inject #PF to guest due to failed permission check. To prevent an spte that was converted into a kernel page with cr0.wp=0 from being written by the kernel after cr0.wp has changed to 1, we make |