All of lore.kernel.org
 help / color / mirror / Atom feed
From: Avi Kivity <avi@redhat.com>
To: Cameron Macdonell <cam@cs.ualberta.ca>
Cc: Anthony Liguori <anthony@codemonkey.ws>, kvm@vger.kernel.org
Subject: Re: [PATCH] Add shared memory PCI device that shares a memory object betweens VMs
Date: Sun, 19 Apr 2009 13:26:12 +0300	[thread overview]
Message-ID: <49EAFC44.9080809@redhat.com> (raw)
In-Reply-To: <AAA6C642-A0E4-4FE3-A4C2-84BCD4C83A8E@cs.ualberta.ca>

Cameron Macdonell wrote:
>
> Hi Avi and Anthony,
>
> Sorry for the top-reply, but we haven't discussed this aspect here 
> before.
>
> I've been thinking about how to implement interrupts.  As far as I can 
> tell, unix domain sockets in Qemu/KVM are used point-to-point with one 
> VM being the server by specifying "server" along with the unix: 
> option.  This works simply for two VMs, but I'm unsure how this can 
> extend to multiple VMs.  How would a server VM know how many clients 
> to wait for?  How can messages then be multicast or broadcast?  Is a 
> separate "interrupt server" necessary?


I don't think unix provides a reliable multicast RPC.  So yes, an 
interrupt server seems necessary.

You could expand its role an make it a "shared memory PCI card server", 
and have it also be responsible for providing the backing file using an 
SCM_RIGHTS fd.  That would reduce setup headaches for users (setting up 
a file for which all VMs have permissions).

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.


  reply	other threads:[~2009-04-19 10:26 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-04-01 15:43 [PATCH] Add shared memory PCI device that shares a memory object betweens VMs Cam Macdonell
2009-04-01 16:29 ` Anthony Liguori
2009-04-01 18:07   ` Avi Kivity
2009-04-01 18:52     ` Anthony Liguori
2009-04-01 20:32       ` Cam Macdonell
2009-04-02  7:07         ` Avi Kivity
2009-04-03 16:54           ` Cam Macdonell
2009-04-02  7:05       ` Avi Kivity
2009-04-19  5:22       ` Cameron Macdonell
2009-04-19 10:26         ` Avi Kivity [this message]
     [not found]           ` <f3b32c250904202348t6514d3efjc691b48c4dafe76a@mail.gmail.com>
2009-04-22 22:41             ` Cam Macdonell
     [not found]               ` <f3b32c250904222355y687c39ecl11c52267a1ea7386@mail.gmail.com>
2009-04-23 16:28                 ` Cam Macdonell

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=49EAFC44.9080809@redhat.com \
    --to=avi@redhat.com \
    --cc=anthony@codemonkey.ws \
    --cc=cam@cs.ualberta.ca \
    --cc=kvm@vger.kernel.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 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.