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SubjectRe: [PATCH 0/2] x86, kvm: fix detection of KVM features when KVM and Hyper-V coexist
On Mon, Jan 27, 2014 at 07:11:28PM +0100, Paolo Bonzini wrote:
> When KVM also presents Hyper-V features (which is useful because Windows
> behaves better), Linux guests prefer KVM because emulated leaves are at
> 0x40000000 and the native ones are at 0x40000100.
>
> However, Linux is then not accounting for the offset when reading the
> available hypervisor features from CPUID. Instead of looking at
> 0x40000101, it will always look at 0x40000001.
>
> This series makes sure that features such as async page faults or steal
> time are available even if, for whatever reason, Hyper-V features are
> enabled.
>
> As a side effect, patch 1 makes a bunch of code non inline, which also
> makes sense since it should only be called during initialization. As
> a result, vmlinux .text size decreases by 96 bytes.
>
> Please review!
>
> Paolo Bonzini (2):
> x86, kvm: cache the base of the KVM cpuid leaves
> x86, kvm: correctly access the KVM_CPUID_FEATURES leaf at 0x40000101
>
> arch/x86/include/asm/kvm_para.h | 33 ++++++++++++---------------------
> arch/x86/kernel/kvm.c | 31 +++++++++++++++++++++++++++++++
> 2 files changed, 43 insertions(+), 21 deletions(-)
>
> --
> 1.8.3.1

Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>



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