* [PATCH] tools/libxc: Correct use of X86_XSS_MASK in guest xstate generation
@ 2016-04-19 17:27 Andrew Cooper
2016-04-19 17:39 ` Wei Liu
0 siblings, 1 reply; 3+ messages in thread
From: Andrew Cooper @ 2016-04-19 17:27 UTC (permalink / raw)
To: Xen-devel; +Cc: Andrew Cooper, Ian Jackson, Wei Liu, Jan Beulich
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(-)
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
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] tools/libxc: Correct use of X86_XSS_MASK in guest xstate generation
2016-04-19 17:27 [PATCH] tools/libxc: Correct use of X86_XSS_MASK in guest xstate generation Andrew Cooper
@ 2016-04-19 17:39 ` Wei Liu
2016-04-20 13:48 ` Ian Jackson
0 siblings, 1 reply; 3+ messages in thread
From: Wei Liu @ 2016-04-19 17:39 UTC (permalink / raw)
To: Andrew Cooper; +Cc: Wei Liu, Ian Jackson, Jan Beulich, Xen-devel
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
>
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] tools/libxc: Correct use of X86_XSS_MASK in guest xstate generation
2016-04-19 17:39 ` Wei Liu
@ 2016-04-20 13:48 ` Ian Jackson
0 siblings, 0 replies; 3+ messages in thread
From: Ian Jackson @ 2016-04-20 13:48 UTC (permalink / raw)
To: Wei Liu; +Cc: Andrew Cooper, Jan Beulich, Xen-devel
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)
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2016-04-20 13:48 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-04-19 17:27 [PATCH] tools/libxc: Correct use of X86_XSS_MASK in guest xstate generation Andrew Cooper
2016-04-19 17:39 ` Wei Liu
2016-04-20 13:48 ` Ian Jackson
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).