From: Anthony Liguori <anthony@codemonkey.ws>
To: kvm-ia64@vger.kernel.org
Subject: Re: [PATCH] virtio: Define and use per-architecture "pfn shift" constants
Date: Thu, 06 Nov 2008 16:22:05 +0000 [thread overview]
Message-ID: <491319AD.5070501@codemonkey.ws> (raw)
In-Reply-To: <200811052254.04409.hollisb@us.ibm.com>
Hollis Blanchard wrote:
> On Thu, 2008-11-06 at 10:49 +0000, Mark McLoughlin wrote:
>
>> But actually, why do we align the size anyway?
>>
>
> I assume it's so that the last page in the ring (containing the "used"
> fields) could be safely mapped into another guest's address space,
> without fear of exposing other data.
>
> I don't know how valuable that is, but that's not really my concern so I
> preserved the behavior.
>
>
>> Also might make sense for vring_init() and vring_size() not to take a
>> pagesize argument and hard-code them to use VRING_PAGE_SIZE.
>>
>
> I think that's a good idea. Anthony mentioned earlier the code was done
> this way so it could be copied to userspace, where PAGE_SIZE is
> unavailable, but that isn't an issue if we switch to VRING_PAGE_SIZE.
>
Agreed.
Regards,
Anthony Liguori
WARNING: multiple messages have this Message-ID (diff)
From: Anthony Liguori <anthony@codemonkey.ws>
To: Hollis Blanchard <hollisb-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
Cc: Mark McLoughlin <markmc-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org,
kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
kvm-ppc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
kvm-ia64-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH] virtio: Define and use per-architecture "pfn shift" constants
Date: Thu, 06 Nov 2008 16:22:05 +0000 [thread overview]
Message-ID: <491319AD.5070501@codemonkey.ws> (raw)
In-Reply-To: <1225986626.8620.28.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
Hollis Blanchard wrote:
> On Thu, 2008-11-06 at 10:49 +0000, Mark McLoughlin wrote:
>
>> But actually, why do we align the size anyway?
>>
>
> I assume it's so that the last page in the ring (containing the "used"
> fields) could be safely mapped into another guest's address space,
> without fear of exposing other data.
>
> I don't know how valuable that is, but that's not really my concern so I
> preserved the behavior.
>
>
>> Also might make sense for vring_init() and vring_size() not to take a
>> pagesize argument and hard-code them to use VRING_PAGE_SIZE.
>>
>
> I think that's a good idea. Anthony mentioned earlier the code was done
> this way so it could be copied to userspace, where PAGE_SIZE is
> unavailable, but that isn't an issue if we switch to VRING_PAGE_SIZE.
>
Agreed.
Regards,
Anthony Liguori
WARNING: multiple messages have this Message-ID (diff)
From: Anthony Liguori <anthony-rdkfGonbjUSkNkDKm+mE6A@public.gmane.org>
To: Hollis Blanchard <hollisb-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
Cc: Mark McLoughlin <markmc-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org,
kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
kvm-ppc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
kvm-ia64-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH] virtio: Define and use per-architecture "pfn shift" constants
Date: Thu, 06 Nov 2008 10:22:05 -0600 [thread overview]
Message-ID: <491319AD.5070501@codemonkey.ws> (raw)
In-Reply-To: <1225986626.8620.28.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
Hollis Blanchard wrote:
> On Thu, 2008-11-06 at 10:49 +0000, Mark McLoughlin wrote:
>
>> But actually, why do we align the size anyway?
>>
>
> I assume it's so that the last page in the ring (containing the "used"
> fields) could be safely mapped into another guest's address space,
> without fear of exposing other data.
>
> I don't know how valuable that is, but that's not really my concern so I
> preserved the behavior.
>
>
>> Also might make sense for vring_init() and vring_size() not to take a
>> pagesize argument and hard-code them to use VRING_PAGE_SIZE.
>>
>
> I think that's a good idea. Anthony mentioned earlier the code was done
> this way so it could be copied to userspace, where PAGE_SIZE is
> unavailable, but that isn't an issue if we switch to VRING_PAGE_SIZE.
>
Agreed.
Regards,
Anthony Liguori
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next prev parent reply other threads:[~2008-11-06 16:22 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-06 4:54 [PATCH] virtio: Define and use per-architecture "pfn shift" constants Hollis Blanchard
2008-11-06 4:54 ` Hollis Blanchard
2008-11-06 4:54 ` Hollis Blanchard
2008-11-06 10:49 ` [PATCH] virtio: Define and use per-architecture "pfn shift" Mark McLoughlin
2008-11-06 10:49 ` [PATCH] virtio: Define and use per-architecture "pfn shift" constants Mark McLoughlin
2008-11-06 10:49 ` [PATCH] virtio: Define and use per-architecture "pfn shift" Mark McLoughlin
2008-11-06 13:59 ` [PATCH] virtio: Define and use per-architecture "pfn shift" constants Anthony Liguori
2008-11-06 13:59 ` Anthony Liguori
2008-11-06 13:59 ` Anthony Liguori
2008-11-06 15:50 ` [PATCH] virtio: Define and use per-architecture "pfn shift" Hollis Blanchard
2008-11-06 15:50 ` [PATCH] virtio: Define and use per-architecture "pfn shift" constants Hollis Blanchard
2008-11-06 15:50 ` [PATCH] virtio: Define and use per-architecture "pfn shift" Hollis Blanchard
2008-11-06 16:22 ` Anthony Liguori [this message]
2008-11-06 16:22 ` [PATCH] virtio: Define and use per-architecture "pfn shift" constants Anthony Liguori
2008-11-06 16:22 ` Anthony Liguori
2008-11-06 20:07 ` Anthony Liguori
2008-11-06 20:07 ` Anthony Liguori
2008-11-06 20:07 ` Anthony Liguori
-- strict thread matches above, loose matches on Subject: below --
2008-11-06 4:49 Hollis Blanchard
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