From: David Woodhouse <dwmw2@infradead.org>
To: Alex Williamson <alex.williamson@redhat.com>,
"Tian, Kevin" <kevin.tian@intel.com>,
"Kay, Allen M" <allen.m.kay@intel.com>,
Gerd Hoffmann <kraxel@redhat.com>
Cc: "igvt-g@ml01.01.org" <igvt-g@ml01.01.org>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
Eduardo Habkost <ehabkost@redhat.com>,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
Cao jin <caoj.fnst@cn.fujitsu.com>,
"vfio-users@redhat.com" <vfio-users@redhat.com>
Subject: Re: [Qemu-devel] [Xen-devel] [iGVT-g] [vfio-users] [PATCH v3 00/11] igd passthrough chipset tweaks
Date: Tue, 02 Feb 2016 15:06:04 +0000 [thread overview]
Message-ID: <1454425564.4788.61.camel@infradead.org> (raw)
In-Reply-To: <1454424840.10542.18.camel@redhat.com>
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On Tue, 2016-02-02 at 07:54 -0700, Alex Williamson wrote:
>
> I first glance I like it, but there's a problem, it assumes there is a
> host driver for the device that will permanently release the device from
> the RMRR even after the device is unbound. Currently we don't have a
> requirement that the user must first bind the device to a native host
> driver, unbind it, and only then is it eligible for device assignment.
It doesn't *have* to be a full native driver. It can be a PCI quirk
(the USB controllers could potentially do it that way, although they
don't). Or a stub 'shut it down' driver, potentially even done somehow
through VFIO.
But fundamentally, in all of these cases you have to do *something* to
stop the BIOS-controlled DMA. Otherwise the RMRR shouldn't have been
there in the first place, surely?
But for the gfx case... what *do* we have to do? Does the VMM (and the
VM's BIOS, between them) have to provision a "stolen" region of guest
memory and point the gfx framebuffer at that?
Once we have a proper handle on precisely what needs to happen, we can
have a better conversation about where/how to do that...
--
David Woodhouse Open Source Technology Centre
David.Woodhouse@intel.com Intel Corporation
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next prev parent reply other threads:[~2016-02-02 15:06 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-05 11:41 [Qemu-devel] [PATCH v3 00/11] igd passthrough chipset tweaks Gerd Hoffmann
2016-01-05 11:41 ` [Qemu-devel] [PATCH v3 01/11] pc: wire up TYPE_IGD_PASSTHROUGH_I440FX_PCI_DEVICE for !xen Gerd Hoffmann
2016-01-05 11:41 ` [Qemu-devel] [PATCH v3 02/11] pc: remove has_igd_gfx_passthru global Gerd Hoffmann
2016-01-06 14:32 ` [Qemu-devel] [Xen-devel] " Stefano Stabellini
2016-01-19 15:09 ` [Qemu-devel] " Eduardo Habkost
2016-01-05 11:41 ` [Qemu-devel] [PATCH v3 03/11] pc: move igd support code to igd.c Gerd Hoffmann
2016-01-05 11:41 ` [Qemu-devel] [PATCH v3 04/11] igd: switch TYPE_IGD_PASSTHROUGH_I440FX_PCI_DEVICE to realize Gerd Hoffmann
2016-01-06 14:32 ` Stefano Stabellini
2016-01-23 14:51 ` Eduardo Habkost
2016-01-25 8:59 ` Gerd Hoffmann
2016-01-25 11:53 ` Stefano Stabellini
2016-01-05 11:41 ` [Qemu-devel] [PATCH v3 05/11] igd: TYPE_IGD_PASSTHROUGH_I440FX_PCI_DEVICE: call parent realize Gerd Hoffmann
2016-01-06 14:41 ` Stefano Stabellini
2016-01-06 15:45 ` Gerd Hoffmann
2016-01-19 15:13 ` Eduardo Habkost
2016-01-20 9:10 ` Gerd Hoffmann
2016-01-23 14:52 ` Eduardo Habkost
2016-01-05 11:41 ` [Qemu-devel] [PATCH v3 06/11] igd: use defines for standard pci config space offsets Gerd Hoffmann
2016-01-06 14:43 ` Stefano Stabellini
2016-01-05 11:41 ` [Qemu-devel] [PATCH v3 07/11] igd: revamp host config read Gerd Hoffmann
2016-01-06 15:02 ` Stefano Stabellini
2016-01-06 15:51 ` Gerd Hoffmann
2016-01-06 16:23 ` [Qemu-devel] [Xen-devel] " Stefano Stabellini
2016-01-05 11:41 ` [Qemu-devel] [PATCH v3 08/11] igd: add q35 support Gerd Hoffmann
2016-01-05 11:41 ` [Qemu-devel] [PATCH v3 09/11] igd: move igd-passthrough-isa-bridge to igd.c too Gerd Hoffmann
2016-01-05 11:41 ` [Qemu-devel] [PATCH v3 10/11] igd: handle igd-passthrough-isa-bridge setup in realize() Gerd Hoffmann
2016-01-06 15:29 ` Stefano Stabellini
2016-01-06 15:52 ` Gerd Hoffmann
2016-01-05 11:41 ` [Qemu-devel] [PATCH v3 11/11] igd: move igd-passthrough-isa-bridge creation to machine init Gerd Hoffmann
2016-01-06 15:36 ` Stefano Stabellini
2016-01-07 7:38 ` Gerd Hoffmann
2016-01-07 13:10 ` Stefano Stabellini
2016-01-07 15:50 ` Gerd Hoffmann
2016-01-08 11:20 ` Stefano Stabellini
2016-01-08 12:12 ` Stefano Stabellini
2016-01-08 12:32 ` Gerd Hoffmann
2016-01-08 12:38 ` Stefano Stabellini
2016-01-05 13:07 ` [Qemu-devel] [PATCH v3 00/11] igd passthrough chipset tweaks Michael S. Tsirkin
2016-01-28 19:35 ` [Qemu-devel] [vfio-users] " Alex Williamson
2016-01-29 2:22 ` [Qemu-devel] [iGVT-g] " Kay, Allen M
2016-01-29 2:54 ` Alex Williamson
2016-01-29 6:21 ` Jike Song
2016-01-29 21:58 ` Kay, Allen M
2016-02-02 7:07 ` Tian, Kevin
2016-02-02 19:10 ` Kay, Allen M
2016-02-02 19:37 ` Alex Williamson
2016-02-02 23:32 ` Kay, Allen M
2016-01-29 7:09 ` [Qemu-devel] " Gerd Hoffmann
2016-01-29 17:59 ` Alex Williamson
2016-01-30 1:18 ` [Qemu-devel] [iGVT-g] " Kay, Allen M
2016-01-31 17:42 ` Alex Williamson
2016-02-02 0:04 ` Kay, Allen M
2016-02-02 6:42 ` [Qemu-devel] [Xen-devel] " Tian, Kevin
2016-02-02 11:50 ` David Woodhouse
2016-02-02 14:54 ` Alex Williamson
2016-02-02 15:06 ` David Woodhouse [this message]
2016-02-02 14:38 ` [Qemu-devel] " Alex Williamson
2016-02-01 12:49 ` [Qemu-devel] " Gerd Hoffmann
2016-02-01 22:16 ` Alex Williamson
2016-02-02 7:43 ` Gerd Hoffmann
2016-02-02 7:01 ` [Qemu-devel] [iGVT-g] " Tian, Kevin
2016-02-02 8:56 ` Gerd Hoffmann
2016-02-02 16:31 ` Kevin O'Connor
2016-02-02 16:49 ` Laszlo Ersek
2016-02-02 20:18 ` Alex Williamson
2016-02-03 6:08 ` Tian, Kevin
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