From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dor Laor Subject: Re: [kvm-devel] [PATCH 3/3] virtio PCI device Date: Tue, 27 Nov 2007 15:27:25 +0200 Message-ID: <474C1B3D.3050905@qumranet.com> References: <11944899922822-git-send-email-aliguori@us.ibm.com> <11944900141678-git-send-email-aliguori@us.ibm.com> <11944900152750-git-send-email-aliguori@us.ibm.com> <11944900163817-git-send-email-aliguori@us.ibm.com> <4742F6B7.20503@qumranet.com> <474300AD.4060509@us.ibm.com> <4743076F.8000105@qumranet.com> <47435CCB.1050506@us.ibm.com> <4743DAA4.70800@qumranet.com> <4747051C.3090903@us.ibm.com> <4747122F.1070905@qumranet.com> <474B1BF3.20901@us.ibm.com> <474BDD28.7050801@qumranet.com> <474BDEDE.6060603@de.ibm.com> <474BE319.502@qumranet.com> <474BEDAB.3000305@de.ibm.com> <474BEF28.9010005@qumranet.com> <474BF157.3080709@de.ibm.com> Reply-To: dor.laor-atKUWr5tajBWk0Htik3J/w@public.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0290008509==" Return-path: In-Reply-To: <474BF157.3080709-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Mime-version: 1.0 Sender: lguest-bounces+glkvl-lguest=m.gmane.org-mnsaURCQ41sdnm+yROfE0A@public.gmane.org Errors-To: lguest-bounces+glkvl-lguest=m.gmane.org-mnsaURCQ41sdnm+yROfE0A@public.gmane.org To: carsteno-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org Cc: Eric Van Hensbergen , carsteno-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org, kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, lguest , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, virtualization-qjLDD68F18O7TbgM5vRIOg@public.gmane.org List-Id: virtualization@lists.linuxfoundation.org This is a multi-part message in MIME format. --===============0290008509== Content-Type: multipart/alternative; boundary="------------060205080908080905070503" This is a multi-part message in MIME format. --------------060205080908080905070503 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Carsten Otte wrote: > Avi Kivity wrote: > >>> We intend to bind our virtio devices to PCI too, so that they look the >>> same in Linux userland across architectures. >>> >> Ouch. >> > That was my initial opinion too, but HPA has come up with a lean and > clean PCI binding for lguest. I think we should seriously consider > using that over the current qemu device emulation based thing. > > There are two solutions for this problem: 1. Use hypercalls and supply mechanism for hypercall patching for qemu. This way we can make s390 & qemu/xen happy. 2. Have two transport mechanism for virtio. Actually this is what we have today (but not yet merged) - lguest uses the pci config space but without using Anthony's pci module. We'll have virtio host i(qemu/kernel) implementation for the shared memory and interface. We'll have pci transport for x86 that glues the above and a virtual transport for s390 and paravirt_ops. Both transports will be based on Rusty's config space. This is the idea I suggested in Tuscon: ----- ------------ --------- | 9p | | network | | block | ------ ------------ --------- | virtio interface| ---------------- ----------- -------------------------------------------------- | virtio_pci| OR | virtio_vbus (includes configs & hypercall/portio) | ----------- -------------------------------------------------- ----------- ------------- | virtio_ring| |virtio_config| ----------- ------------- Regards, Dor > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2005. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > kvm-devel mailing list > kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org > https://lists.sourceforge.net/lists/listinfo/kvm-devel > > --------------060205080908080905070503 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Carsten Otte wrote: 
Avi Kivity wrote:
  
We intend to bind our virtio devices to PCI too, so that they look the 
same in Linux userland across architectures.
      
Ouch.
    
That was my initial opinion too, but HPA has come up with a lean and 
clean PCI binding for lguest. I think we should seriously consider 
using that over the current qemu device emulation based thing.
There are two solutions for this problem:
1. Use hypercalls and supply mechanism for hypercall patching for qemu.
    This way we can make s390 & qemu/xen happy.
2. Have two transport mechanism for virtio.
    Actually this is what we have today (but not yet merged) - lguest uses the pci config space
    but without using Anthony's pci module.
    We'll have virtio host i(qemu/kernel) implementation for the shared memory and interface.
    We'll have pci transport for x86 that glues the above and a virtual transport for s390 and paravirt_ops.
    Both transports will be based on Rusty's config space.
    This is the idea I suggested in Tuscon:

     -----         ------------            ---------
     | 9p |         |  network |             |  block |
     ------       ------------            ---------
                      | virtio interface|
                      ----------------
                -----------                   --------------------------------------------------
                | virtio_pci|      OR       | virtio_vbus (includes configs & hypercall/portio) |
                -----------                   --------------------------------------------------
           -----------           -------------
           | virtio_ring|            |virtio_config|
           -----------           -------------

Regards,
Dor
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