* [PATCH] x86/bigmem: eliminate struct domain address width restriction
@ 2015-08-26 7:41 Jan Beulich
2015-08-26 8:55 ` Andrew Cooper
2015-09-01 10:57 ` Ian Campbell
0 siblings, 2 replies; 5+ messages in thread
From: Jan Beulich @ 2015-08-26 7:41 UTC (permalink / raw)
To: xen-devel; +Cc: Andrew Cooper, Keir Fraser
[-- Attachment #1: Type: text/plain, Size: 1283 bytes --]
PDX-es are 64 bits wide in that case, and hence no limit needs to be
enforced.
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -204,6 +204,7 @@ smap_check_policy_t smap_policy_change(s
return old_policy;
}
+#ifndef CONFIG_BIGMEM
/*
* The hole may be at or above the 44-bit boundary, so we need to determine
* the total bit count until reaching 32 significant (not squashed out) bits
@@ -225,10 +226,12 @@ static unsigned int __init noinline _dom
return bits;
}
+#endif
struct domain *alloc_domain_struct(void)
{
struct domain *d;
+#ifndef CONFIG_BIGMEM
/*
* We pack the PDX of the domain structure into a 32-bit field within
* the page_info structure. Hence the MEMF_bits() restriction.
@@ -237,12 +240,16 @@ struct domain *alloc_domain_struct(void)
if ( unlikely(!bits) )
bits = _domain_struct_bits();
+#else
+# define bits 0
+#endif
BUILD_BUG_ON(sizeof(*d) > PAGE_SIZE);
d = alloc_xenheap_pages(0, MEMF_bits(bits));
if ( d != NULL )
clear_page(d);
return d;
+#undef bits
}
void free_domain_struct(struct domain *d)
[-- Attachment #2: x86-bigmem-no-struct-domain-limit.patch --]
[-- Type: text/plain, Size: 1342 bytes --]
x86/bigmem: eliminate struct domain address width restriction
PDX-es are 64 bits wide in that case, and hence no limit needs to be
enforced.
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -204,6 +204,7 @@ smap_check_policy_t smap_policy_change(s
return old_policy;
}
+#ifndef CONFIG_BIGMEM
/*
* The hole may be at or above the 44-bit boundary, so we need to determine
* the total bit count until reaching 32 significant (not squashed out) bits
@@ -225,10 +226,12 @@ static unsigned int __init noinline _dom
return bits;
}
+#endif
struct domain *alloc_domain_struct(void)
{
struct domain *d;
+#ifndef CONFIG_BIGMEM
/*
* We pack the PDX of the domain structure into a 32-bit field within
* the page_info structure. Hence the MEMF_bits() restriction.
@@ -237,12 +240,16 @@ struct domain *alloc_domain_struct(void)
if ( unlikely(!bits) )
bits = _domain_struct_bits();
+#else
+# define bits 0
+#endif
BUILD_BUG_ON(sizeof(*d) > PAGE_SIZE);
d = alloc_xenheap_pages(0, MEMF_bits(bits));
if ( d != NULL )
clear_page(d);
return d;
+#undef bits
}
void free_domain_struct(struct domain *d)
[-- Attachment #3: Type: text/plain, Size: 126 bytes --]
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^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] x86/bigmem: eliminate struct domain address width restriction
2015-08-26 7:41 [PATCH] x86/bigmem: eliminate struct domain address width restriction Jan Beulich
@ 2015-08-26 8:55 ` Andrew Cooper
2015-09-01 10:57 ` Ian Campbell
1 sibling, 0 replies; 5+ messages in thread
From: Andrew Cooper @ 2015-08-26 8:55 UTC (permalink / raw)
To: Jan Beulich, xen-devel; +Cc: Keir Fraser
On 26/08/15 08:41, Jan Beulich wrote:
> PDX-es are 64 bits wide in that case, and hence no limit needs to be
> enforced.
>
> Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] x86/bigmem: eliminate struct domain address width restriction
2015-08-26 7:41 [PATCH] x86/bigmem: eliminate struct domain address width restriction Jan Beulich
2015-08-26 8:55 ` Andrew Cooper
@ 2015-09-01 10:57 ` Ian Campbell
2015-09-01 11:58 ` Jan Beulich
1 sibling, 1 reply; 5+ messages in thread
From: Ian Campbell @ 2015-09-01 10:57 UTC (permalink / raw)
To: Jan Beulich, xen-devel; +Cc: Andrew Cooper, Keir Fraser
On Wed, 2015-08-26 at 01:41 -0600, Jan Beulich wrote:
> @@ -225,10 +226,12 @@ static unsigned int __init noinline _dom
>
> return bits;
> }
> +#endif
>
> struct domain *alloc_domain_struct(void)
> {
> struct domain *d;
> +#ifndef CONFIG_BIGMEM
> /*
> * We pack the PDX of the domain structure into a 32-bit field
> within
> * the page_info structure. Hence the MEMF_bits() restriction.
> @@ -237,12 +240,16 @@ struct domain *alloc_domain_struct(void)
>
> if ( unlikely(!bits) )
> bits = _domain_struct_bits();
> +#else
> +# define bits 0
const unsigned int bits = 0;
Seems nicer than the trailing #undef?
> +#endif
>
> BUILD_BUG_ON(sizeof(*d) > PAGE_SIZE);
> d = alloc_xenheap_pages(0, MEMF_bits(bits));
> if ( d != NULL )
> clear_page(d);
> return d;
> +#undef bits
> }
>
> void free_domain_struct(struct domain *d)
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] x86/bigmem: eliminate struct domain address width restriction
2015-09-01 10:57 ` Ian Campbell
@ 2015-09-01 11:58 ` Jan Beulich
2015-09-01 12:14 ` Ian Campbell
0 siblings, 1 reply; 5+ messages in thread
From: Jan Beulich @ 2015-09-01 11:58 UTC (permalink / raw)
To: Ian Campbell; +Cc: Andrew Cooper, Keir Fraser, xen-devel
>>> On 01.09.15 at 12:57, <ian.campbell@citrix.com> wrote:
> On Wed, 2015-08-26 at 01:41 -0600, Jan Beulich wrote:
>> @@ -225,10 +226,12 @@ static unsigned int __init noinline _dom
>>
>> return bits;
>> }
>> +#endif
>>
>> struct domain *alloc_domain_struct(void)
>> {
>> struct domain *d;
>> +#ifndef CONFIG_BIGMEM
>> /*
>> * We pack the PDX of the domain structure into a 32-bit field
>> within
>> * the page_info structure. Hence the MEMF_bits() restriction.
>> @@ -237,12 +240,16 @@ struct domain *alloc_domain_struct(void)
>>
>> if ( unlikely(!bits) )
>> bits = _domain_struct_bits();
>> +#else
>> +# define bits 0
>
> const unsigned int bits = 0;
>
> Seems nicer than the trailing #undef?
Hmm, yes, in cases like this I agree (assuming that all compiler
versions we care about will be intelligent enough to eliminate the
variable).
Jan
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] x86/bigmem: eliminate struct domain address width restriction
2015-09-01 11:58 ` Jan Beulich
@ 2015-09-01 12:14 ` Ian Campbell
0 siblings, 0 replies; 5+ messages in thread
From: Ian Campbell @ 2015-09-01 12:14 UTC (permalink / raw)
To: Jan Beulich; +Cc: Andrew Cooper, Keir Fraser, xen-devel
On Tue, 2015-09-01 at 05:58 -0600, Jan Beulich wrote:
> >
> > > > On 01.09.15 at 12:57, <ian.campbell@citrix.com> wrote:
> > On Wed, 2015-08-26 at 01:41 -0600, Jan Beulich wrote:
> > > @@ -225,10 +226,12 @@ static unsigned int __init noinline _dom
> > >
> > > return bits;
> > > }
> > > +#endif
> > >
> > > struct domain *alloc_domain_struct(void)
> > > {
> > > struct domain *d;
> > > +#ifndef CONFIG_BIGMEM
> > > /*
> > > * We pack the PDX of the domain structure into a 32-bit field
> > > within
> > > * the page_info structure. Hence the MEMF_bits() restriction.
> > > @@ -237,12 +240,16 @@ struct domain *alloc_domain_struct(void)
> > >
> > > if ( unlikely(!bits) )
> > > bits = _domain_struct_bits();
> > > +#else
> > > +# define bits 0
> >
> > const unsigned int bits = 0;
> >
> > Seems nicer than the trailing #undef?
>
> Hmm, yes, in cases like this I agree (assuming that all compiler
> versions we care about will be intelligent enough to eliminate the
> variable).
Even if it weren't I don't think it would be noticeable in
alloc_domain_struct().
Ian.
^ permalink raw reply [flat|nested] 5+ messages in thread
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2015-08-26 7:41 [PATCH] x86/bigmem: eliminate struct domain address width restriction Jan Beulich
2015-08-26 8:55 ` Andrew Cooper
2015-09-01 10:57 ` Ian Campbell
2015-09-01 11:58 ` Jan Beulich
2015-09-01 12:14 ` Ian Campbell
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