From: "Michael S. Tsirkin" <mst@redhat.com>
To: Kashyap Chamarthy <kchamart@redhat.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] PCI(e): Documentation "io-reserve" and related properties?
Date: Thu, 6 Jun 2019 14:20:18 -0400 [thread overview]
Message-ID: <20190606141904-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20190606161943.GA9657@paraplu>
On Thu, Jun 06, 2019 at 06:19:43PM +0200, Kashyap Chamarthy wrote:
> Hi folks,
>
> Today I learnt about some obscure PCIe-related properties, in context of
> the adding PCIe root ports to a guest, namely:
>
> io-reserve
> mem-reserve
> bus-reserve
> pref32-reserve
> pref64-reserve
>
> Unfortunately, the commit[*] that added them provided no documentation
> whatsover.
>
> In my scenario, I was specifically wondering about what does
> "io-reserve" mean, in what context to use it, etc. (But documentation
> about other properties is also welcome.)
>
> Anyone more well-versed in this area care to shed some light?
>
>
> [*] 6755e618d0 (hw/pci: add PCI resource reserve capability to legacy
> PCI bridge, 2018-08-21)
So normally bios would reserve just enough io space to satisfy all
devices behind a bridge. What if you intend to hotplug more devices?
These properties allow you to ask bios to reserve extra space.
> --
> /kashyap
next prev parent reply other threads:[~2019-06-06 18:23 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-06 16:19 [Qemu-devel] PCI(e): Documentation "io-reserve" and related properties? Kashyap Chamarthy
2019-06-06 18:20 ` Michael S. Tsirkin [this message]
2019-06-07 11:43 ` Andrea Bolognani
2019-06-11 10:15 ` Marcel Apfelbaum
2019-06-11 7:21 ` Kashyap Chamarthy
2019-06-11 10:19 ` Marcel Apfelbaum
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=20190606141904-mutt-send-email-mst@kernel.org \
--to=mst@redhat.com \
--cc=kchamart@redhat.com \
--cc=qemu-devel@nongnu.org \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).