From: "Durrant, Paul" <pdurrant@amazon.co.uk>
To: "Roger Pau Monné" <roger.pau@citrix.com>,
"Jason Andryuk" <jandryuk@gmail.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
Stefano Stabellini <sstabellini@kernel.org>,
"marmarek@invisiblethingslab.com"
<marmarek@invisiblethingslab.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
Simon Gaiser <simon@invisiblethingslab.com>,
Anthony Perard <anthony.perard@citrix.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Subject: RE: [Xen-devel] [PATCH 6/6] xen-pt: Round pci regions sizes to XEN_PAGE_SIZE
Date: Wed, 15 Jan 2020 08:33:02 +0000 [thread overview]
Message-ID: <ed1ca41d72bd49c59e5e25044a0a85e0@EX13D32EUC003.ant.amazon.com> (raw)
In-Reply-To: <20200114180457.GG11756@Air-de-Roger>
> -----Original Message-----
>
> > Linux PCI subsytem has an option resource_alignment that can be
> > applied to either a single device or all devices. Booting with
> > pci=resource_aligment=4096 will align each device to a page. Do you
> > think pciback should force resource_alignment=4096 for dom0?
>
That sounds like a good idea.
> Ideally Xen should keep track of the BARs position and size and refuse
> to passthrough devices that have BARs sharing a page with other
> devices BARs.
>
> > Are
> > there other MMIO ranges to be concerned about adjacent to BARs?
>
> IIRC you can have two BARs of different devices in the same 4K page,
> BARs are only aligned to it's size, so BARs smaller than 4K are not
> required to be page aligned.
If we had a notion of assignment groups for this, as well as devices sharing requester id, then Xen would not need to refuse pass-through, it would just require that all devices sharing the page were passed through as a unit.
Paul
prev parent reply other threads:[~2020-01-15 13:24 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-11 18:02 [Qemu-devel] [PATCH 0/6] Xen stubdom support Jason Andryuk
2019-03-11 18:02 ` [Qemu-devel] [PATCH 1/6] xen: Introduce -xen-stubdom option Jason Andryuk
2019-03-11 18:06 ` Paolo Bonzini
2019-03-11 19:46 ` Jason Andryuk
2019-03-11 18:02 ` [Qemu-devel] [PATCH 2/6] xen: Move xenstore initialization to common location Jason Andryuk
2019-03-11 18:02 ` [Qemu-devel] [PATCH 3/6] xen: Skip backend initialization for stubdom Jason Andryuk
2019-03-11 18:02 ` [Qemu-devel] [PATCH 4/6] xen: Set HVM_PARAM_DM_DOMAIN for stubdom on older Xen Jason Andryuk
2019-03-11 18:02 ` [Qemu-devel] [PATCH 5/6] xen-pt: Hide MSI-X from xen stubdoms Jason Andryuk
2019-03-11 18:02 ` [Qemu-devel] [PATCH 6/6] xen-pt: Round pci regions sizes to XEN_PAGE_SIZE Jason Andryuk
[not found] ` <ee0da83d3f054e72ae450437c8834d04@AMSPEX02CL02.citrite.net>
[not found] ` <CAKf6xpujVs3RPJcb+2vqPZFcYwhdDcjbt=S_+awjPuPFpFHsPw@mail.gmail.com>
[not found] ` <57dc1083d20a469785f05a2e5250a820@AMSPEX02CL02.citrite.net>
[not found] ` <cd5f1ecc-576f-b7d0-3090-4f3e4faf6148@citrix.com>
[not found] ` <CAKf6xpt4XYXn2xHJoVY_ibcaHSw-ED10V7ZGNKuDdkiJ93RS0A@mail.gmail.com>
[not found] ` <20190322030936.fkiajz5ifgaejkd4@MacBook-Air-de-Roger.local>
[not found] ` <CAKf6xptP_b-+FuscjsTK9G7pMeVS8drvA_t+xb5bdF2zxxmWfA@mail.gmail.com>
2020-01-13 19:01 ` [Xen-devel] " Jason Andryuk
2020-01-14 10:04 ` Roger Pau Monné
2020-01-14 14:41 ` Jason Andryuk
2020-01-14 18:04 ` Roger Pau Monné
2020-01-15 8:33 ` Durrant, Paul [this message]
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