* [PATCH] x86/mm: fix mod_l1_entry() return value when encountering r/o MMIO page
@ 2012-06-20 15:18 Jan Beulich
2012-06-20 16:04 ` Keir Fraser
0 siblings, 1 reply; 2+ messages in thread
From: Jan Beulich @ 2012-06-20 15:18 UTC (permalink / raw)
To: xen-devel
[-- Attachment #1: Type: text/plain, Size: 692 bytes --]
While putting together the workaround announced in
http://lists.xen.org/archives/html/xen-devel/2012-06/msg00709.html, I
found that mod_l1_entry(), upon encountering a set bit in
mmio_ro_ranges, would return 1 instead of 0 (the removal of the write
permission is supposed to be entirely transparent to the caller, even
more so to the calling guest).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -1875,6 +1875,7 @@ static int mod_l1_entry(l1_pgentry_t *pl
break;
case 1:
l1e_remove_flags(nl1e, _PAGE_RW);
+ rc = 0;
break;
}
if ( page )
[-- Attachment #2: x86-mm-mod-l1-entry-mmio-ro.patch --]
[-- Type: text/plain, Size: 761 bytes --]
x86/mm: fix mod_l1_entry() return value when encountering r/o MMIO page
While putting together the workaround announced in
http://lists.xen.org/archives/html/xen-devel/2012-06/msg00709.html, I
found that mod_l1_entry(), upon encountering a set bit in
mmio_ro_ranges, would return 1 instead of 0 (the removal of the write
permission is supposed to be entirely transparent to the caller, even
more so to the calling guest).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -1875,6 +1875,7 @@ static int mod_l1_entry(l1_pgentry_t *pl
break;
case 1:
l1e_remove_flags(nl1e, _PAGE_RW);
+ rc = 0;
break;
}
if ( page )
[-- Attachment #3: Type: text/plain, Size: 126 bytes --]
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^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] x86/mm: fix mod_l1_entry() return value when encountering r/o MMIO page
2012-06-20 15:18 [PATCH] x86/mm: fix mod_l1_entry() return value when encountering r/o MMIO page Jan Beulich
@ 2012-06-20 16:04 ` Keir Fraser
0 siblings, 0 replies; 2+ messages in thread
From: Keir Fraser @ 2012-06-20 16:04 UTC (permalink / raw)
To: Jan Beulich, xen-devel
On 20/06/2012 16:18, "Jan Beulich" <JBeulich@suse.com> wrote:
> While putting together the workaround announced in
> http://lists.xen.org/archives/html/xen-devel/2012-06/msg00709.html, I
> found that mod_l1_entry(), upon encountering a set bit in
> mmio_ro_ranges, would return 1 instead of 0 (the removal of the write
> permission is supposed to be entirely transparent to the caller, even
> more so to the calling guest).
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
> --- a/xen/arch/x86/mm.c
> +++ b/xen/arch/x86/mm.c
> @@ -1875,6 +1875,7 @@ static int mod_l1_entry(l1_pgentry_t *pl
> break;
> case 1:
> l1e_remove_flags(nl1e, _PAGE_RW);
> + rc = 0;
> break;
> }
> if ( page )
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 2+ messages in thread
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2012-06-20 15:18 [PATCH] x86/mm: fix mod_l1_entry() return value when encountering r/o MMIO page Jan Beulich
2012-06-20 16:04 ` Keir Fraser
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