On Tue, Apr 19, 2016 at 06:27:05PM +0100, Andrew Cooper wrote:
> c/s 75f9455e "tools/libxc: Calculate xstate cpuid leaf from guest information"
> incorrectly inverted the shift and mask when using X86_XSS_MASK. Luckily, the
> mask is currently zero, avoiding incorrect calculations.
>
> While adjusting this, use an explcit uint32_t cast rather than masking against
> 0xffffffff.
>
> Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
> ---
> CC: Ian Jackson <ian.jack...@eu.citrix.com>
> CC: Wei Liu <wei.l...@citrix.com>
> CC: Jan Beulich <jbeul...@suse.com>
>
> Submitted-from: A punt, on the Cam, during the the hackathon, because.
Acked-by: Wei Liu <wei.l...@citrix.com>
Release-acked-by: Wei Liu <wei.l...@citrix.com>
On a punt, too, because
> ---
> tools/libxc/xc_cpuid_x86.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/tools/libxc/xc_cpuid_x86.c b/tools/libxc/xc_cpuid_x86.c
> index 6d14904..84f4e08 100644
> --- a/tools/libxc/xc_cpuid_x86.c
> +++ b/tools/libxc/xc_cpuid_x86.c
> @@ -460,7 +460,7 @@ static void xc_cpuid_config_xsave(xc_interface *xch,
> {
> case 0:
> /* EAX: low 32bits of xfeature_enabled_mask */
> - regs[0] = guest_xfeature_mask & 0xFFFFFFFF;
> + regs[0] = (uint32_t)guest_xfeature_mask;
> /* EDX: high 32bits of xfeature_enabled_mask */
> regs[3] = guest_xfeature_mask >> 32;
> /* ECX: max size required by all HW features */
> @@ -487,8 +487,8 @@ static void xc_cpuid_config_xsave(xc_interface *xch,
>
> if ( test_bit(X86_FEATURE_XSAVES, info->featureset) )
> {
> - regs[2] = guest_xfeature_mask & X86_XSS_MASK & 0xFFFFFFFF;
> - regs[3] = (guest_xfeature_mask >> 32) & X86_XSS_MASK;
> + regs[2] = (uint32_t)(guest_xfeature_mask & X86_XSS_MASK);
> + regs[3] = (guest_xfeature_mask & X86_XSS_MASK) >> 32;
> }
> else
> regs[2] = regs[3] = 0;
> --
> 1.9.1
>
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