I''ve been considering buying a second video and sound card, and then using PCI passthrough with a Windows domU for gaming. Has anyone tried this? I''m curious as to whether it''s fast enough for recent games to be playable. The video card and CPU can handle gaming fine, but I''m not sure how much Xen would effect that. So has anyone done this? How well did it work? _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Do, Apr 12, 2007 at 05:34:29 -0400, Andrew Yates wrote:> I''ve been considering buying a second video and sound card, and then > using PCI passthrough with a Windows domU for gaming. > Has anyone tried this? I''m curious as to whether it''s fast enough for > recent games to be playable. The video card and CPU can handle gaming > fine, but I''m not sure how much Xen would effect that. So has anyone > done this? How well did it work? >Do HVM domain support PCI passthrough?> _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users-- WBR, i.m.chubin _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> -----Original Message----- > From: xen-users-bounces@lists.xensource.com > [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of > Igor Chubin > Sent: 13 April 2007 10:29 > To: Andrew Yates > Cc: xen-users@lists.xensource.com > Subject: Re: [Xen-users] gaming in a windows domU? > > On Do, Apr 12, 2007 at 05:34:29 -0400, Andrew Yates wrote: > > I''ve been considering buying a second video and sound card, and then > > using PCI passthrough with a Windows domU for gaming. > > Has anyone tried this? I''m curious as to whether it''s fast > enough for > > recent games to be playable. The video card and CPU can > handle gaming > > fine, but I''m not sure how much Xen would effect that. So has anyone > > done this? How well did it work? > > > > Do HVM domain support PCI passthrough?No. But that''s the EASY part to solve. The hard part is that the HVM OS isn''t aware that what it thinks is a physical address is in fact not really the address that the memory controller is accessing when the software accesses a virtual address. If we simplify things[1] to make it easy to explain: Dom0 uses 0..256MB, HVM DomU uses 256..512MB, but thinks it got memory from 0..256MB. DomU tells the hardware that there is some data at 0x100000 (1MB), but we should really add 256MB to that address. So the hardware will use something that lives at 1MB in the Dom0 instead. Most likely, this will just lead to complete garbage being sent to the hardware, which isn''t so bad. If it happens to be something that actually works with the hardware it may send your list of passwords to a random address on the internet or some such! [1] In reality, each 4KB of guest memory could come from any 4K section of the machines memory, so it''s not as simple as just adding an offset - but that''s just a slight complication on top of the fact that DomU doesn''t actually know that it''s memory isn''t where it thinks it is. -- Mats> > > _______________________________________________ > > Xen-users mailing list > > Xen-users@lists.xensource.com > > http://lists.xensource.com/xen-users > > -- > WBR, i.m.chubin > > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users > > >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> -----Original Message----- > From: xen-users-bounces@lists.xensource.com > [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of > Andrew Yates > Sent: 12 April 2007 22:34 > To: xen-users@lists.xensource.com > Subject: [Xen-users] gaming in a windows domU? > > I''ve been considering buying a second video and sound card, and then > using PCI passthrough with a Windows domU for gaming.Won''t work with currently available (home) hardware (software also won''t let it happen, but that''s EASY to solve compared to getting the hardware necessary). If you manage to get a IBM server with a Calgary IOMMU, and the relevant software to drive the IOMMU, I suppose you''d have some small chance.> Has anyone tried this? I''m curious as to whether it''s fast enough for > recent games to be playable. The video card and CPU can handle gaming > fine, but I''m not sure how much Xen would effect that. So has anyone > done this? How well did it work?If you were to have an IOMMU in the system, and you don''t have too many (any?) other domains interfering, I''d say you should get reasonable graphics and overall performance. -- Mats> > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users > > >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Fr, Apr 13, 2007 at 11:53:05 +0200, Petersson, Mats wrote:> > > > -----Original Message----- > > From: xen-users-bounces@lists.xensource.com > > [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of > > Igor Chubin > > Sent: 13 April 2007 10:29 > > To: Andrew Yates > > Cc: xen-users@lists.xensource.com > > Subject: Re: [Xen-users] gaming in a windows domU? > > > > On Do, Apr 12, 2007 at 05:34:29 -0400, Andrew Yates wrote: > > > I''ve been considering buying a second video and sound card, and then > > > using PCI passthrough with a Windows domU for gaming. > > > Has anyone tried this? I''m curious as to whether it''s fast > > enough for > > > recent games to be playable. The video card and CPU can > > handle gaming > > > fine, but I''m not sure how much Xen would effect that. So has anyone > > > done this? How well did it work? > > > > > > > Do HVM domain support PCI passthrough? > > No. But that''s the EASY part to solve. The hard part is that the HVM OS > isn''t aware that what it thinks is a physical address is in fact not > really the address that the memory controller is accessing when the > software accesses a virtual address. >Mats, thank you for the answer. As far as I know the problem will be eliminated when as soon as IOMMU will be available. Does IOMMU really solve the problem? Question related to previous one: HVM Windows Domains have poor IO-performance due to necessity of usage of qemu device model (and correspondent drivers). Will the problem be eliminated (or alleviated at least) with appearance of the IOMMU? And question #3: How is Intel virtualization technology [1] related with IOMMU? [1] http://www.intel.com/technology/itj/2006/v10i3/2-io/1-abstract.htm> If we simplify things[1] to make it easy to explain: Dom0 uses 0..256MB, > HVM DomU uses 256..512MB, but thinks it got memory from 0..256MB. DomU > tells the hardware that there is some data at 0x100000 (1MB), but we > should really add 256MB to that address. So the hardware will use > something that lives at 1MB in the Dom0 instead. Most likely, this will > just lead to complete garbage being sent to the hardware, which isn''t so > bad. If it happens to be something that actually works with the hardware > it may send your list of passwords to a random address on the internet > or some such! > > [1] In reality, each 4KB of guest memory could come from any 4K section > of the machines memory, so it''s not as simple as just adding an offset - > but that''s just a slight complication on top of the fact that DomU > doesn''t actually know that it''s memory isn''t where it thinks it is. > > -- > Mats > > > > > _______________________________________________ > > > Xen-users mailing list > > > Xen-users@lists.xensource.com > > > http://lists.xensource.com/xen-users > > > > -- > > WBR, i.m.chubin > > > > > > _______________________________________________ > > Xen-users mailing list > > Xen-users@lists.xensource.com > > http://lists.xensource.com/xen-users > > > > > > > > > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users-- WBR, i.m.chubin _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> -----Original Message----- > From: Igor Chubin [mailto:igor@chub.in] > Sent: 13 April 2007 11:52 > To: Petersson, Mats > Cc: xen-users@lists.xensource.com > Subject: Re: [Xen-users] gaming in a windows domU? > > On Fr, Apr 13, 2007 at 11:53:05 +0200, Petersson, Mats wrote: > > > > > > > -----Original Message----- > > > From: xen-users-bounces@lists.xensource.com > > > [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of > > > Igor Chubin > > > Sent: 13 April 2007 10:29 > > > To: Andrew Yates > > > Cc: xen-users@lists.xensource.com > > > Subject: Re: [Xen-users] gaming in a windows domU? > > > > > > On Do, Apr 12, 2007 at 05:34:29 -0400, Andrew Yates wrote: > > > > I''ve been considering buying a second video and sound > card, and then > > > > using PCI passthrough with a Windows domU for gaming. > > > > Has anyone tried this? I''m curious as to whether it''s fast > > > enough for > > > > recent games to be playable. The video card and CPU can > > > handle gaming > > > > fine, but I''m not sure how much Xen would effect that. > So has anyone > > > > done this? How well did it work? > > > > > > > > > > Do HVM domain support PCI passthrough? > > > > No. But that''s the EASY part to solve. The hard part is > that the HVM OS > > isn''t aware that what it thinks is a physical address is in fact not > > really the address that the memory controller is accessing when the > > software accesses a virtual address. > > > > Mats, thank you for the answer. > > As far as I know the problem will be eliminated > when as soon as IOMMU will be available. > Does IOMMU really solve the problem?Yes, it solves this and also the security problem of having a device owned by guest X read/write memory of guest Y (which is another potential problem).> > Question related to previous one: > HVM Windows Domains have poor IO-performance due to > necessity of usage of qemu device model (and correspondent drivers). > Will the problem be eliminated (or alleviated at least) > with appearance of the IOMMU?Yes. IOMMU will also allow better performance. However, para-virtual drivers can also solve this (at least improve it dramatically). PV are drivers that are added to the HVM OS to allow> > > And question #3: > How is Intel virtualization technology [1] related with IOMMU? > > [1] http://www.intel.com/technology/itj/2006/v10i3/2-io/1-abstract.htm >Intel''s VT-d is the same concept as AMD''s IOMMU concept. I haven''t looked at the details of it, so I can''t say if it''s EXACTLY the same, or just a similar solution. [There''s almost certainly SOME differences, because the two systems are developed by different groups of people, who have a similar problem to solve, which usually means a similar solution with some differences]. -- Mats> > > If we simplify things[1] to make it easy to explain: Dom0 > uses 0..256MB, > > HVM DomU uses 256..512MB, but thinks it got memory from > 0..256MB. DomU > > tells the hardware that there is some data at 0x100000 (1MB), but we > > should really add 256MB to that address. So the hardware will use > > something that lives at 1MB in the Dom0 instead. Most > likely, this will > > just lead to complete garbage being sent to the hardware, > which isn''t so > > bad. If it happens to be something that actually works with > the hardware > > it may send your list of passwords to a random address on > the internet > > or some such! > > > > [1] In reality, each 4KB of guest memory could come from > any 4K section > > of the machines memory, so it''s not as simple as just > adding an offset - > > but that''s just a slight complication on top of the fact that DomU > > doesn''t actually know that it''s memory isn''t where it thinks it is. > > > > -- > > Mats > > > > > > > _______________________________________________ > > > > Xen-users mailing list > > > > Xen-users@lists.xensource.com > > > > http://lists.xensource.com/xen-users > > > > > > -- > > > WBR, i.m.chubin > > > > > > > > > _______________________________________________ > > > Xen-users mailing list > > > Xen-users@lists.xensource.com > > > http://lists.xensource.com/xen-users > > > > > > > > > > > > > > > > > _______________________________________________ > > Xen-users mailing list > > Xen-users@lists.xensource.com > > http://lists.xensource.com/xen-users > > -- > WBR, i.m.chubin > > > >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users