KVM: MTRR: treat memory as writeback if MTRR is disabled in guest CPUID
authorPaolo Bonzini <pbonzini@redhat.com>
Tue, 22 Dec 2015 14:20:00 +0000 (15:20 +0100)
committerPaolo Bonzini <pbonzini@redhat.com>
Tue, 22 Dec 2015 14:29:00 +0000 (15:29 +0100)
commite24dea2afc6a0852983dc741072d8e96155e13f5
tree80b972cf9cd865559d6b6aae01392bc5bc4321b3
parentfa7c4ebd5ae0c22f9908436303106a9ffcf0cf42
KVM: MTRR: treat memory as writeback if MTRR is disabled in guest CPUID

Virtual machines can be run with CPUID such that there are no MTRRs.
In that case, the firmware will never enable MTRRs and it is obviously
undesirable to run the guest entirely with UC memory.  Check out guest
CPUID, and use WB memory if MTRR do not exist.

Cc: qemu-stable@nongnu.org
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=107561
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
arch/x86/kvm/cpuid.h
arch/x86/kvm/mtrr.c