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authorAndy Lutomirski <luto@amacapital.net>2014-10-08 09:02:13 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-10-18 10:09:03 -0700
commitd974baa398f34393db76be45f7d4d04fbdbb4a0a (patch)
tree781bdd81421b75e92e98aafbeb2d7ad5845d0fc5 /kernel
parent2e923b0251932ad4a82cc87ec1443a1f1d17073e (diff)
x86,kvm,vmx: Preserve CR4 across VM entry
CR4 isn't constant; at least the TSD and PCE bits can vary. TBH, treating CR0 and CR3 as constant scares me a bit, too, but it looks like it's correct. This adds a branch and a read from cr4 to each vm entry. Because it is extremely likely that consecutive entries into the same vcpu will have the same host cr4 value, this fixes up the vmcs instead of restoring cr4 after the fact. A subsequent patch will add a kernel-wide cr4 shadow, reducing the overhead in the common case to just two memory reads and a branch. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Cc: stable@vger.kernel.org Cc: Petr Matousek <pmatouse@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
0 files changed, 0 insertions, 0 deletions