| Message ID | 1461086825-394-1-git-send-email-andrew.cooper3@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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.cooper3@citrix.com> > --- > CC: Ian Jackson <Ian.Jackson@eu.citrix.com> > CC: Wei Liu <wei.liu2@citrix.com> > CC: Jan Beulich <JBeulich@suse.com> > > Submitted-from: A punt, on the Cam, during the the hackathon, because. Acked-by: Wei Liu <wei.liu2@citrix.com> Release-acked-by: Wei Liu <wei.liu2@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 >
Wei Liu writes ("Re: [PATCH] tools/libxc: Correct use of X86_XSS_MASK in guest xstate generation"):
> On Tue, Apr 19, 2016 at 06:27:05PM +0100, Andrew Cooper wrote:
> > Submitted-from: A punt, on the Cam, during the the hackathon, because.
>
> Acked-by: Wei Liu <wei.liu2@citrix.com>
> Release-acked-by: Wei Liu <wei.liu2@citrix.com>
>
> On a punt, too, because
Queued, thanks.
Ian.
(at his desk)
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;
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.cooper3@citrix.com> --- CC: Ian Jackson <Ian.Jackson@eu.citrix.com> CC: Wei Liu <wei.liu2@citrix.com> CC: Jan Beulich <JBeulich@suse.com> Submitted-from: A punt, on the Cam, during the the hackathon, because. --- tools/libxc/xc_cpuid_x86.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)