diff options
| author | Dongxiao Xu <dongxiao.xu@intel.com> | 2013-02-04 11:50:43 +0800 |
|---|---|---|
| committer | Marcelo Tosatti <mtosatti@redhat.com> | 2013-02-05 23:28:07 -0200 |
| commit | c08800a56cb8622bb61577abb4a120c6fdc4b9be (patch) | |
| tree | c9195953c1e901dfa44238facd4fc1402d1b9fc8 /arch/microblaze/boot | |
| parent | 4293b5e5a68074431cafa74d549c1327ba1d0deb (diff) | |
KVM: VMX: disable SMEP feature when guest is in non-paging mode
SMEP is disabled if CPU is in non-paging mode in hardware.
However KVM always uses paging mode to emulate guest non-paging
mode with TDP. To emulate this behavior, SMEP needs to be manually
disabled when guest switches to non-paging mode.
We met an issue that, SMP Linux guest with recent kernel (enable
SMEP support, for example, 3.5.3) would crash with triple fault if
setting unrestricted_guest=0. This is because KVM uses an identity
mapping page table to emulate the non-paging mode, where the page
table is set with USER flag. If SMEP is still enabled in this case,
guest will meet unhandlable page fault and then crash.
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Dongxiao Xu <dongxiao.xu@intel.com>
Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch/microblaze/boot')
0 files changed, 0 insertions, 0 deletions