From: Stefan Hajnoczi <stefanha@redhat.com>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Jailhouse <jailhouse-dev@googlegroups.com>,
"liang yan" <lyan@suse.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
qemu-devel <qemu-devel@nongnu.org>,
"virtio-comment@lists.oasis-open.org"
<virtio-comment@lists.oasis-open.org>,
"Alex Bennée" <alex.bennee@linaro.org>
Subject: Re: [virtio-comment] [RFC] ivshmem v2: Shared memory device specification
Date: Mon, 27 Jul 2020 13:29:39 +0100 [thread overview]
Message-ID: <20200727122939.GB386429@stefanha-x1.localdomain> (raw)
In-Reply-To: <10df6427-eab0-d3b8-4624-ede98ff7ef09@siemens.com>
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On Thu, Jul 23, 2020 at 09:02:09AM +0200, Jan Kiszka wrote:
> On 23.07.20 08:54, Stefan Hajnoczi wrote:
> > On Fri, Jul 17, 2020 at 06:15:58PM +0200, Jan Kiszka wrote:
> > > On 15.07.20 15:27, Stefan Hajnoczi wrote:
> > > > On Mon, May 25, 2020 at 09:58:28AM +0200, Jan Kiszka wrote:
> >
> > Thanks for the responses. It would be great to update the spec with
> > these clarifications.
> >
> > > > > If BAR 2 is not present, the shared memory region is not relocatable
> > > > > by the user. In that case, the hypervisor has to implement the Base
> > > > > Address register in the vendor-specific capability.
> > > >
> > > > What does relocatable mean in this context?
> > >
> > > That the guest can decide (via BAR) where the resource should show up in the
> > > physical guest address space. We do not want to support this in setups like
> > > for static partitioning hypervisors, and then we use that side-channel
> > > read-only configuration.
> >
> > I see. I'm not sure what is vendor-specific about non-relocatable shared
> > memory. I guess it could be added to the spec too?
>
> That "vendor-specific" comes from the PCI spec which - to my understanding -
> provides us no other means to introduce registers to the config space that
> are outside of the PCI spec. I could introduce a name for the ivshmem vendor
> cap and use that name here - would that be better?
Sounds good.
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next prev parent reply other threads:[~2020-07-27 12:35 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-25 7:58 [RFC] ivshmem v2: Shared memory device specification Jan Kiszka
2020-06-17 15:32 ` Alex Bennée
2020-06-17 16:10 ` Jan Kiszka
2020-07-15 13:27 ` [virtio-comment] " Stefan Hajnoczi
2020-07-17 16:15 ` Jan Kiszka
2020-07-23 6:54 ` Stefan Hajnoczi
2020-07-23 7:02 ` Jan Kiszka
2020-07-27 12:29 ` Stefan Hajnoczi [this message]
2020-07-27 13:20 ` Michael S. Tsirkin
2020-07-27 13:39 ` [virtio-comment] " Jan Kiszka
2020-07-27 13:56 ` Michael S. Tsirkin
2020-07-27 14:17 ` Jan Kiszka
2020-07-27 14:19 ` Michael S. Tsirkin
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