From: Avi Kivity <avi@qumranet.com>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
kvm-devel@lists.sourceforge.net, general@lists.openfabrics.org
Subject: Re: [kvm-devel] [PATCH][RFC] pte notifiers -- support for external page tables
Date: Wed, 05 Sep 2007 23:17:06 +0300 [thread overview]
Message-ID: <46DF0EC2.7090408@qumranet.com> (raw)
In-Reply-To: <1189022183.10802.184.camel@localhost.localdomain>
Rusty Russell wrote:
> On Wed, 2007-09-05 at 22:32 +0300, Avi Kivity wrote:
>
>> [resend due to bad alias expansion resulting in some recipients
>> being bogus]
>>
>> Some hardware and software systems maintain page tables outside the normal
>> Linux page tables, which reference userspace memory. This includes
>> Infiniband, other RDMA-capable devices, and kvm (with a pending patch).
>>
>
> And lguest. I can't tell until I've actually implemented it, but I
> think it will seriously reduce the need for page pinning which is why
> only root can currently launch guests.
>
>
Ah yes, lguest.
> My concern is locking: this is called with the page lock held, and I
> guess we have to bump the guest out if it's currently running.
>
This will complicate kvm's locking too. We usually take kvm->lock to do
mmu ops, but that is now a mutex.
--
Any sufficiently difficult bug is indistinguishable from a feature.
WARNING: multiple messages have this Message-ID (diff)
From: Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
To: Rusty Russell <rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>
Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
general-ZwoEplunGu1OwGhvXhtEPSCwEArCW2h5@public.gmane.org
Subject: Re: [PATCH][RFC] pte notifiers -- support for external page tables
Date: Wed, 05 Sep 2007 23:17:06 +0300 [thread overview]
Message-ID: <46DF0EC2.7090408@qumranet.com> (raw)
In-Reply-To: <1189022183.10802.184.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
Rusty Russell wrote:
> On Wed, 2007-09-05 at 22:32 +0300, Avi Kivity wrote:
>
>> [resend due to bad alias expansion resulting in some recipients
>> being bogus]
>>
>> Some hardware and software systems maintain page tables outside the normal
>> Linux page tables, which reference userspace memory. This includes
>> Infiniband, other RDMA-capable devices, and kvm (with a pending patch).
>>
>
> And lguest. I can't tell until I've actually implemented it, but I
> think it will seriously reduce the need for page pinning which is why
> only root can currently launch guests.
>
>
Ah yes, lguest.
> My concern is locking: this is called with the page lock held, and I
> guess we have to bump the guest out if it's currently running.
>
This will complicate kvm's locking too. We usually take kvm->lock to do
mmu ops, but that is now a mutex.
--
Any sufficiently difficult bug is indistinguishable from a feature.
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WARNING: multiple messages have this Message-ID (diff)
From: Avi Kivity <avi@qumranet.com>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
kvm-devel@lists.sourceforge.net, general@lists.openfabrics.org
Subject: Re: [kvm-devel] [PATCH][RFC] pte notifiers -- support for external page tables
Date: Wed, 05 Sep 2007 23:17:06 +0300 [thread overview]
Message-ID: <46DF0EC2.7090408@qumranet.com> (raw)
In-Reply-To: <1189022183.10802.184.camel@localhost.localdomain>
Rusty Russell wrote:
> On Wed, 2007-09-05 at 22:32 +0300, Avi Kivity wrote:
>
>> [resend due to bad alias expansion resulting in some recipients
>> being bogus]
>>
>> Some hardware and software systems maintain page tables outside the normal
>> Linux page tables, which reference userspace memory. This includes
>> Infiniband, other RDMA-capable devices, and kvm (with a pending patch).
>>
>
> And lguest. I can't tell until I've actually implemented it, but I
> think it will seriously reduce the need for page pinning which is why
> only root can currently launch guests.
>
>
Ah yes, lguest.
> My concern is locking: this is called with the page lock held, and I
> guess we have to bump the guest out if it's currently running.
>
This will complicate kvm's locking too. We usually take kvm->lock to do
mmu ops, but that is now a mutex.
--
Any sufficiently difficult bug is indistinguishable from a feature.
--
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next prev parent reply other threads:[~2007-09-05 20:20 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-05 19:32 [PATCH][RFC] pte notifiers -- support for external page tables Avi Kivity
2007-09-05 19:32 ` Avi Kivity
2007-09-05 19:32 ` Avi Kivity
2007-09-05 19:56 ` [kvm-devel] " Rusty Russell
2007-09-05 19:56 ` Rusty Russell
2007-09-05 19:56 ` [ofa-general] " Rusty Russell
2007-09-05 20:17 ` Avi Kivity [this message]
2007-09-05 20:17 ` Avi Kivity
2007-09-05 20:17 ` Avi Kivity
2007-09-06 4:28 ` Shaohua Li
2007-09-06 4:28 ` Shaohua Li
2007-09-06 4:28 ` Shaohua Li
2007-09-06 8:38 ` Avi Kivity
2007-09-06 8:38 ` Avi Kivity
2007-09-06 8:38 ` [ofa-general] " Avi Kivity
2007-09-06 11:39 ` Andi Kleen
2007-09-06 13:18 ` Avi Kivity
2007-09-06 15:17 ` Avi Kivity
2007-09-06 15:17 ` Avi Kivity
2007-09-06 15:17 ` [ofa-general] " Avi Kivity
2007-09-06 13:28 ` Andi Kleen
2007-09-06 13:28 ` Andi Kleen
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