From: "Tian, Kevin" <kevin.tian@intel.com>
To: 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>,
Alex Williamson <alex.williamson@redhat.com>,
Cao jin <caoj.fnst@cn.fujitsu.com>,
"vfio-users@redhat.com" <vfio-users@redhat.com>
Subject: Re: [Qemu-devel] [iGVT-g] [vfio-users] [PATCH v3 00/11] igd passthrough chipset tweaks
Date: Wed, 3 Feb 2016 06:08:30 +0000 [thread overview]
Message-ID: <AADFC41AFE54684AB9EE6CBC0274A5D15F79CBCE@SHSMSX103.ccr.corp.intel.com> (raw)
In-Reply-To: <1454403380.9300.49.camel@redhat.com>
> From: Gerd Hoffmann [mailto:kraxel@redhat.com]
> Sent: Tuesday, February 02, 2016 4:56 PM
>
> Hi,
>
> > > I'd have qemu copy the data on 0xfc write then, so things continue to
> > > work without updating seabios. So, the firmware has to allocate space,
> > > reserve it etc., and programming the 0xfc register. Qemu has to make
> > > sure the opregion appears at the address written by the firmware, by
> > > whatever method it prefers.
> >
> > Yup. It's Qemu's responsibility to expose opregion content.
> >
> > btw, prefer to do copying here. It's pointless to allow write from guest
> > side. One write example is SWSCI mailbox, thru which gfx driver can
> > trigger some SCI event to communicate with BIOS (specifically ACPI
> > methods here), mostly for some monitor operations. However it's
> > not a right thing for guest to trigger host SCI and thus kick host
> > ACPI methods.
>
> Thanks.
>
> So, question again how we do that best. Option one being the mmap way,
> i.e. basically what the patches posted by alex are doing. Option two
> being the fw_cfg way, i.e. place a opregion copy in fw_cfg and have
> seabios not only set 0xfc, but also store the opregion there by copying
> from fw_cfg.
>
> Advantage of option one is that we'll keep the option to do things in a
> different way in the future, without breaking the guest/qemu interface.
>
> Disadvantage is that it'll cause hugepage mappings to be splitted.
>
based on where you pick up the gfn to map or copy opregion. If you look
at physical, it's usually close to mmio region where several other reserved
e820 entries also exist. If we do same for virtual opregion, it shouldn't
impact hugepage.
Thanks
Kevin
WARNING: multiple messages have this Message-ID (diff)
From: "Tian, Kevin" <kevin.tian@intel.com>
To: 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>,
Alex Williamson <alex.williamson@redhat.com>,
Cao jin <caoj.fnst@cn.fujitsu.com>,
"vfio-users@redhat.com" <vfio-users@redhat.com>
Subject: Re: [iGVT-g] [vfio-users] [PATCH v3 00/11] igd passthrough chipset tweaks
Date: Wed, 3 Feb 2016 06:08:30 +0000 [thread overview]
Message-ID: <AADFC41AFE54684AB9EE6CBC0274A5D15F79CBCE@SHSMSX103.ccr.corp.intel.com> (raw)
In-Reply-To: <1454403380.9300.49.camel@redhat.com>
> From: Gerd Hoffmann [mailto:kraxel@redhat.com]
> Sent: Tuesday, February 02, 2016 4:56 PM
>
> Hi,
>
> > > I'd have qemu copy the data on 0xfc write then, so things continue to
> > > work without updating seabios. So, the firmware has to allocate space,
> > > reserve it etc., and programming the 0xfc register. Qemu has to make
> > > sure the opregion appears at the address written by the firmware, by
> > > whatever method it prefers.
> >
> > Yup. It's Qemu's responsibility to expose opregion content.
> >
> > btw, prefer to do copying here. It's pointless to allow write from guest
> > side. One write example is SWSCI mailbox, thru which gfx driver can
> > trigger some SCI event to communicate with BIOS (specifically ACPI
> > methods here), mostly for some monitor operations. However it's
> > not a right thing for guest to trigger host SCI and thus kick host
> > ACPI methods.
>
> Thanks.
>
> So, question again how we do that best. Option one being the mmap way,
> i.e. basically what the patches posted by alex are doing. Option two
> being the fw_cfg way, i.e. place a opregion copy in fw_cfg and have
> seabios not only set 0xfc, but also store the opregion there by copying
> from fw_cfg.
>
> Advantage of option one is that we'll keep the option to do things in a
> different way in the future, without breaking the guest/qemu interface.
>
> Disadvantage is that it'll cause hugepage mappings to be splitted.
>
based on where you pick up the gfn to map or copy opregion. If you look
at physical, it's usually close to mmio region where several other reserved
e820 entries also exist. If we do same for virtual opregion, it shouldn't
impact hugepage.
Thanks
Kevin
next prev parent reply other threads:[~2016-02-03 6:08 UTC|newest]
Thread overview: 132+ 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 ` 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 ` Gerd Hoffmann
2016-01-05 11:41 ` [Qemu-devel] [PATCH v3 02/11] pc: remove has_igd_gfx_passthru global Gerd Hoffmann
2016-01-05 11:41 ` Gerd Hoffmann
2016-01-06 14:32 ` [Qemu-devel] [Xen-devel] " Stefano Stabellini
2016-01-06 14:32 ` Stefano Stabellini
2016-01-19 15:09 ` [Qemu-devel] " Eduardo Habkost
2016-01-19 15:09 ` 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 ` 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
2016-01-05 11:41 ` Gerd Hoffmann
2016-01-06 14:32 ` [Qemu-devel] " Stefano Stabellini
2016-01-06 14:32 ` Stefano Stabellini
2016-01-23 14:51 ` [Qemu-devel] " Eduardo Habkost
2016-01-23 14:51 ` Eduardo Habkost
2016-01-25 8:59 ` [Qemu-devel] " Gerd Hoffmann
2016-01-25 8:59 ` Gerd Hoffmann
2016-01-25 11:53 ` [Qemu-devel] " Stefano Stabellini
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
2016-01-05 11:41 ` Gerd Hoffmann
2016-01-06 14:41 ` [Qemu-devel] " Stefano Stabellini
2016-01-06 14:41 ` Stefano Stabellini
2016-01-06 15:45 ` [Qemu-devel] " Gerd Hoffmann
2016-01-06 15:45 ` Gerd Hoffmann
2016-01-19 15:13 ` [Qemu-devel] " Eduardo Habkost
2016-01-19 15:13 ` Eduardo Habkost
2016-01-20 9:10 ` [Qemu-devel] " Gerd Hoffmann
2016-01-20 9:10 ` Gerd Hoffmann
2016-01-23 14:52 ` [Qemu-devel] " Eduardo Habkost
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
2016-01-05 11:41 ` Gerd Hoffmann
2016-01-06 14:43 ` [Qemu-devel] " Stefano Stabellini
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
2016-01-05 11:41 ` Gerd Hoffmann
2016-01-06 15:02 ` [Qemu-devel] " Stefano Stabellini
2016-01-06 15:02 ` Stefano Stabellini
2016-01-06 15:51 ` [Qemu-devel] " Gerd Hoffmann
2016-01-06 15:51 ` Gerd Hoffmann
2016-01-06 16:23 ` [Qemu-devel] [Xen-devel] " Stefano Stabellini
2016-01-06 16:23 ` Stefano Stabellini
2016-01-05 11:41 ` [Qemu-devel] [PATCH v3 08/11] igd: add q35 support Gerd Hoffmann
2016-01-05 11:41 ` 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 ` Gerd Hoffmann
2016-01-05 11:41 ` [Qemu-devel] [PATCH v3 10/11] igd: handle igd-passthrough-isa-bridge setup in realize() Gerd Hoffmann
2016-01-05 11:41 ` Gerd Hoffmann
2016-01-06 15:29 ` [Qemu-devel] " Stefano Stabellini
2016-01-06 15:29 ` Stefano Stabellini
2016-01-06 15:52 ` [Qemu-devel] " Gerd Hoffmann
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
2016-01-05 11:41 ` Gerd Hoffmann
2016-01-06 15:36 ` [Qemu-devel] " Stefano Stabellini
2016-01-06 15:36 ` Stefano Stabellini
2016-01-07 7:38 ` [Qemu-devel] " Gerd Hoffmann
2016-01-07 7:38 ` Gerd Hoffmann
2016-01-07 13:10 ` [Qemu-devel] " Stefano Stabellini
2016-01-07 13:10 ` Stefano Stabellini
2016-01-07 15:50 ` [Qemu-devel] " Gerd Hoffmann
2016-01-07 15:50 ` Gerd Hoffmann
2016-01-08 11:20 ` Stefano Stabellini
2016-01-08 11:20 ` Stefano Stabellini
2016-01-08 12:12 ` [Qemu-devel] " Stefano Stabellini
2016-01-08 12:12 ` Stefano Stabellini
2016-01-08 12:32 ` Gerd Hoffmann
2016-01-08 12:32 ` Gerd Hoffmann
2016-01-08 12:38 ` [Qemu-devel] " Stefano Stabellini
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
2016-01-05 13:07 ` Michael S. Tsirkin
2016-01-28 19:35 ` [Qemu-devel] [vfio-users] " Alex Williamson
2016-01-28 19:35 ` Alex Williamson
2016-01-29 2:22 ` [Qemu-devel] [iGVT-g] " Kay, Allen M
2016-01-29 2:22 ` Kay, Allen M
2016-01-29 2:54 ` [Qemu-devel] " Alex Williamson
2016-01-29 2:54 ` Alex Williamson
2016-01-29 6:21 ` [Qemu-devel] " Jike Song
2016-01-29 6:21 ` Jike Song
2016-01-29 21:58 ` [Qemu-devel] " Kay, Allen M
2016-01-29 21:58 ` Kay, Allen M
2016-02-02 7:07 ` [Qemu-devel] " Tian, Kevin
2016-02-02 7:07 ` Tian, Kevin
2016-02-02 19:10 ` [Qemu-devel] " Kay, Allen M
2016-02-02 19:10 ` [iGVT-g] " Kay, Allen M
2016-02-02 19:37 ` [Qemu-devel] [iGVT-g] [vfio-users] " Alex Williamson
2016-02-02 19:37 ` Alex Williamson
2016-02-02 23:32 ` [Qemu-devel] " Kay, Allen M
2016-02-02 23:32 ` Kay, Allen M
2016-01-29 7:09 ` [Qemu-devel] " Gerd Hoffmann
2016-01-29 7:09 ` Gerd Hoffmann
2016-01-29 17:59 ` [Qemu-devel] " Alex Williamson
2016-01-29 17:59 ` Alex Williamson
2016-01-30 1:18 ` [Qemu-devel] [iGVT-g] " Kay, Allen M
2016-01-30 1:18 ` Kay, Allen M
2016-01-31 17:42 ` [Qemu-devel] " Alex Williamson
2016-01-31 17:42 ` Alex Williamson
2016-02-02 0:04 ` [Qemu-devel] " Kay, Allen M
2016-02-02 0:04 ` Kay, Allen M
2016-02-02 6:42 ` [Qemu-devel] [Xen-devel] " Tian, Kevin
2016-02-02 6:42 ` Tian, Kevin
2016-02-02 11:50 ` [Qemu-devel] " David Woodhouse
2016-02-02 11:50 ` David Woodhouse
2016-02-02 14:54 ` [Qemu-devel] " Alex Williamson
2016-02-02 14:54 ` Alex Williamson
2016-02-02 15:06 ` [Qemu-devel] " David Woodhouse
2016-02-02 15:06 ` David Woodhouse
2016-02-02 14:38 ` [Qemu-devel] " Alex Williamson
2016-02-02 14:38 ` Alex Williamson
2016-02-01 12:49 ` [Qemu-devel] " Gerd Hoffmann
2016-02-01 12:49 ` Gerd Hoffmann
2016-02-01 22:16 ` [Qemu-devel] " Alex Williamson
2016-02-01 22:16 ` Alex Williamson
2016-02-02 7:43 ` [Qemu-devel] [vfio-users] " Gerd Hoffmann
2016-02-02 7:43 ` Gerd Hoffmann
2016-02-02 7:01 ` [Qemu-devel] [iGVT-g] " Tian, Kevin
2016-02-02 7:01 ` [iGVT-g] " Tian, Kevin
2016-02-02 8:56 ` [Qemu-devel] [iGVT-g] [vfio-users] " Gerd Hoffmann
2016-02-02 8:56 ` Gerd Hoffmann
2016-02-02 16:31 ` [Qemu-devel] " Kevin O'Connor
2016-02-02 16:31 ` Kevin O'Connor
2016-02-02 16:49 ` [Qemu-devel] " Laszlo Ersek
2016-02-02 16:49 ` Laszlo Ersek
2016-02-02 20:18 ` [Qemu-devel] " Alex Williamson
2016-02-02 20:18 ` Alex Williamson
2016-02-03 6:08 ` Tian, Kevin [this message]
2016-02-03 6:08 ` Tian, Kevin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=AADFC41AFE54684AB9EE6CBC0274A5D15F79CBCE@SHSMSX103.ccr.corp.intel.com \
--to=kevin.tian@intel.com \
--cc=alex.williamson@redhat.com \
--cc=caoj.fnst@cn.fujitsu.com \
--cc=ehabkost@redhat.com \
--cc=igvt-g@ml01.01.org \
--cc=kraxel@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=stefano.stabellini@eu.citrix.com \
--cc=vfio-users@redhat.com \
--cc=xen-devel@lists.xensource.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.