* [PATCH] x86/domctl: don't waste domain CPUID slot for all zero data
@ 2016-03-22 12:56 Jan Beulich
2016-03-22 15:10 ` Andrew Cooper
0 siblings, 1 reply; 2+ messages in thread
From: Jan Beulich @ 2016-03-22 12:56 UTC (permalink / raw)
To: xen-devel; +Cc: Andrew Cooper, Keir Fraser
[-- Attachment #1: Type: text/plain, Size: 979 bytes --]
domain_cpuid() returns all zeroes anyway when not finding a match, so
there's no need to explicitly store such a set of values.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -714,7 +714,7 @@ long arch_do_domctl(
case XEN_DOMCTL_set_cpuid:
{
- xen_domctl_cpuid_t *ctl = &domctl->u.cpuid;
+ const xen_domctl_cpuid_t *ctl = &domctl->u.cpuid;
cpuid_input_t *cpuid, *unused = NULL;
if ( d == currd ) /* no domain_pause() */
@@ -742,7 +742,12 @@ long arch_do_domctl(
domain_pause(d);
- if ( i < MAX_CPUID_INPUT )
+ if ( !(ctl->eax | ctl->ebx | ctl->ecx | ctl->edx) )
+ {
+ if ( i < MAX_CPUID_INPUT )
+ cpuid->input[0] = XEN_CPUID_INPUT_UNUSED;
+ }
+ else if ( i < MAX_CPUID_INPUT )
*cpuid = *ctl;
else if ( unused )
*unused = *ctl;
[-- Attachment #2: x86-domctl-CPUID-unused.patch --]
[-- Type: text/plain, Size: 1036 bytes --]
x86/domctl: don't waste domain CPUID slot for all zero data
domain_cpuid() returns all zeroes anyway when not finding a match, so
there's no need to explicitly store such a set of values.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -714,7 +714,7 @@ long arch_do_domctl(
case XEN_DOMCTL_set_cpuid:
{
- xen_domctl_cpuid_t *ctl = &domctl->u.cpuid;
+ const xen_domctl_cpuid_t *ctl = &domctl->u.cpuid;
cpuid_input_t *cpuid, *unused = NULL;
if ( d == currd ) /* no domain_pause() */
@@ -742,7 +742,12 @@ long arch_do_domctl(
domain_pause(d);
- if ( i < MAX_CPUID_INPUT )
+ if ( !(ctl->eax | ctl->ebx | ctl->ecx | ctl->edx) )
+ {
+ if ( i < MAX_CPUID_INPUT )
+ cpuid->input[0] = XEN_CPUID_INPUT_UNUSED;
+ }
+ else if ( i < MAX_CPUID_INPUT )
*cpuid = *ctl;
else if ( unused )
*unused = *ctl;
[-- Attachment #3: Type: text/plain, Size: 126 bytes --]
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] x86/domctl: don't waste domain CPUID slot for all zero data
2016-03-22 12:56 [PATCH] x86/domctl: don't waste domain CPUID slot for all zero data Jan Beulich
@ 2016-03-22 15:10 ` Andrew Cooper
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Cooper @ 2016-03-22 15:10 UTC (permalink / raw)
To: Jan Beulich, xen-devel; +Cc: Keir Fraser
On 22/03/16 12:56, Jan Beulich wrote:
slot => slots in the subject.
> domain_cpuid() returns all zeroes anyway when not finding a match, so
> there's no need to explicitly store such a set of values.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2016-03-22 15:27 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-03-22 12:56 [PATCH] x86/domctl: don't waste domain CPUID slot for all zero data Jan Beulich
2016-03-22 15:10 ` Andrew Cooper
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.