Re: [Xen-devel] [v4] libxc: Expose the 1GB pages cpuid flag to guest

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Fri, 2014-11-28 at 18:52 +0800, Liang Li wrote:
> If hardware support the 1GB pages, expose the feature to guest by
> default. Users don't have to use a 'cpuid= ' option in config fil
> e to turn it on.
> 
> If guest use shadow mode, the 1GB pages feature will be hidden from
> guest, this is done in the function hvm_cpuid(). So the change is
> okay for shadow mode case.
> 
> Signed-off-by: Liang Li <liang.z.li@xxxxxxxxx>
> Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx>

FTR although this is strictly speaking a toolstack patch I think the
main ack required should be from the x86 hypervisor guys...

> ---
>  tools/libxc/xc_cpuid_x86.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/tools/libxc/xc_cpuid_x86.c b/tools/libxc/xc_cpuid_x86.c
> index a18b1ff..c97f91a 100644
> --- a/tools/libxc/xc_cpuid_x86.c
> +++ b/tools/libxc/xc_cpuid_x86.c
> @@ -109,6 +109,7 @@ static void amd_xc_cpuid_policy(
>          regs[3] &= (0x0183f3ff | /* features shared with 0x00000001:EDX */
>                      bitmaskof(X86_FEATURE_NX) |
>                      bitmaskof(X86_FEATURE_LM) |
> +                    bitmaskof(X86_FEATURE_PAGE1GB) |
>                      bitmaskof(X86_FEATURE_SYSCALL) |
>                      bitmaskof(X86_FEATURE_MP) |
>                      bitmaskof(X86_FEATURE_MMXEXT) |
> @@ -192,6 +193,7 @@ static void intel_xc_cpuid_policy(
>                      bitmaskof(X86_FEATURE_ABM));
>          regs[3] &= (bitmaskof(X86_FEATURE_NX) |
>                      bitmaskof(X86_FEATURE_LM) |
> +                    bitmaskof(X86_FEATURE_PAGE1GB) |
>                      bitmaskof(X86_FEATURE_SYSCALL) |
>                      bitmaskof(X86_FEATURE_RDTSCP));
>          break;
> @@ -386,6 +388,7 @@ static void xc_cpuid_hvm_policy(
>              clear_bit(X86_FEATURE_LM, regs[3]);
>              clear_bit(X86_FEATURE_NX, regs[3]);
>              clear_bit(X86_FEATURE_PSE36, regs[3]);
> +            clear_bit(X86_FEATURE_PAGE1GB, regs[3]);
>          }
>          break;
>  



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