diff options
| author | Stefan Bader <stefan.bader@canonical.com> | 2013-04-09 16:06:44 +0200 |
|---|---|---|
| committer | Jan Beulich <jbeulich@suse.com> | 2013-04-09 16:06:44 +0200 |
| commit | d5483523365e85c324d06e8e2b025829aae95f41 (patch) | |
| tree | f35d3bf6271aa26a5dccbfed7e74c83c99b22515 /tools/lib/sys_string.h | |
| parent | 77cb78851429a5a8509e3dfed466b2580ad5c60d (diff) | |
| download | xen-d5483523365e85c324d06e8e2b025829aae95f41.tar.gz xen-d5483523365e85c324d06e8e2b025829aae95f41.tar.bz2 xen-d5483523365e85c324d06e8e2b025829aae95f41.zip | |
VMX: Always disable SMEP when guest is in non-paging mode
commit e7dda8ec9fc9020e4f53345cdbb18a2e82e54a65
VMX: disable SMEP feature when guest is in non-paging mode
disabled the SMEP bit if a guest VCPU was using HAP and was not
in paging mode. However I could observe VCPUs getting stuck in
the trampoline after the following patch in the Linux kernel
changed the way CR4 gets set up:
x86, realmode: read cr4 and EFER from kernel for 64-bit trampoline
The change will set CR4 from already set flags which includes the
SMEP bit. On bare metal this does not matter as the CPU is in non-
paging mode at that time. But Xen seems to use the emulated non-
paging mode regardless of HAP (I verified that on the guests I was
seeing the issue, HAP was not used).
Therefor it seems right to unset the SMEP bit for a VCPU that is
not in paging-mode, regardless of its HAP usage.
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Keir Fraser <keir@xen.org>
Acked-by: Dongxiao Xu <dongxiao.xu@intel.com>
master commit: 0d2e673a763bc7c2ddf97fed074eb691d325ecc5
master date: 2013-04-04 10:37:19 +0200
Diffstat (limited to 'tools/lib/sys_string.h')
0 files changed, 0 insertions, 0 deletions