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Re: [Xen-devel] [PATCH] libxl: fix cirrus vga video memory setting with upstream qemu

Il 08/05/2014 12:10, Ian Campbell ha scritto:
On Wed, 2014-05-07 at 14:20 +0200, Fabio Fantoni wrote:
Il 02/05/2014 22:04, Fabio Fantoni ha scritto:
2014-05-02 21:44 GMT+02:00 Don Slutz <dslutz@xxxxxxxxxxx

     On 05/02/14 07:41, Ian Campbell wrote:

         On Sat, 2014-04-19 at 14:16 +0200, Fabio Fantoni wrote:

             Reading one qemu-devel post seems that setting video memory of
             cirrus vga with upstream qemu is wrong even if not show

       You can add my:

     Reviewed-by: Don Slutz <dslutz@xxxxxxxxxxx

     I have a similar code change locally (part of my pending
     list of to dos) (I just changed the global arg...).

         You later provided links but I think the conversation should be
         referenced here.

     I was part of the conversation.  When I was looking into upstreaming
     a change I have (pci_min_hole) to xen & qemu, I was asked by QEMU
     to report if it was not used (i.e. non x86 cpu's).  While I was
     testing my
     change to QEMU under xen I noticed:

     Warning: "-global vga.vram_size_mb=16" not used

     In /var/log/xen/qemu-dm-<guest>.log

     Here is the cross post to xen-devel:

      [Xen-devel] [PATCH v3 2/4] GlobalProperty: Display warning about
     unused -global


         Is this change correct for all versions of mainline qemu which
         might be using with Xen?

     What I know is that "-global cirrus-vga.vgamem_mb=32" does work
     with upstream QEMU 1.5.0, 1.6.0, 1.7.0 and 2.0.0.  I had added a debug
     output into the QEMU version above that show the amount of video ram
     that gets allocated and so the testing was quick and easy.  My
     understanding of QEMU is that when specified this way:

      "-device cirrus-vga,vgamem_mb=32"

     the error checking in QEMU will report when it does not like it:

     qemu-system-x86_64: Property '.vram_size_mb' not found

     (unlike -global).  So while I have not tested it, I would guess that
     any QEMU that accepts "-device cirrus-vga" will also either
     accept the change or report and error and not start. (Note: the
     change from "-vga cirrus" to "-device cirrus-vga" was done since
     4.3.0 and has yet to generate a bug).

Thanks for your reply, probably with my bad english I not understand
good this part of your reply.
I changed to -device following this official qemu doc:
I did several tests of additional vga's parameters without using
the-global in recent days with cirrus, stdvga and qxl, I've never seen
errors and the amount of videoram by domUs seem ok.
I'm not sure who this was addressed to but for my part I am waiting for
a refreshed patch which addresses the questions asked in
<1399030886.32736.63.camel@xxxxxxxxxxxxxxxxxxxxxx> in the commit
message. Those questions have been partially answered here but it seem
that at least Don's comments about which versions it worked with were
wrt a different patch using a different variation on the options.


About qemu version when vgamem_mb property is added is qemu 1.3, I already did detailed reply about it in stdvga patch:
Or you mean something other?

Thanks for any reply and sorry for my bad english.

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