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| author | Paolo Bonzini <pbonzini@redhat.com> | 2014-09-22 13:17:48 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-12-06 15:55:40 -0800 |
| commit | 28b0107f54d780d3e6b193bf5d3d39b57fa0e629 (patch) | |
| tree | 1341e28055f50769d2646ebab2d4f99ff6992234 /lib/audit.c | |
| parent | 5376f5d39c51b6ed6d787095729464000c9d35e8 (diff) | |
| download | lwn-28b0107f54d780d3e6b193bf5d3d39b57fa0e629.tar.gz lwn-28b0107f54d780d3e6b193bf5d3d39b57fa0e629.zip | |
x86: kvm: use alternatives for VMCALL vs. VMMCALL if kernel text is read-only
commit c1118b3602c2329671ad5ec8bdf8e374323d6343 upstream.
On x86_64, kernel text mappings are mapped read-only with CONFIG_DEBUG_RODATA.
In that case, KVM will fail to patch VMCALL instructions to VMMCALL
as required on AMD processors.
The failure mode is currently a divide-by-zero exception, which obviously
is a KVM bug that has to be fixed. However, picking the right instruction
between VMCALL and VMMCALL will be faster and will help if you cannot upgrade
the hypervisor.
Reported-by: Chris Webb <chris@arachsys.com>
Tested-by: Chris Webb <chris@arachsys.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Chris J Arges <chris.j.arges@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'lib/audit.c')
0 files changed, 0 insertions, 0 deletions