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From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: xen-devel@lists.xensource.com, Ian Jackson <Ian.Jackson@eu.citrix.com>
Subject: Re: [Qemu-devel] [PATCH] ioemu/qemu vga: save and restore vram buffer (revised)
Date: Mon, 17 Dec 2007 16:22:11 +0000	[thread overview]
Message-ID: <200712171622.12475.paul@codesourcery.com> (raw)
In-Reply-To: <18278.23285.98750.687170@mariner.uk.xensource.com>

> In any case, vl.c's saving arrangements do save the buffer in
> phys_ram_base - but that isn't what the guest sees in the VGA memory

It doesn't matter what the guest physical mappings (if any) are.

> area.  The guest sees the vga memory-mapped IO registers (whose
> meaning _is_ generally saved by vga.c), plus it can use the VGA memory
> area and those control registers to access the whole of s->vram_ptr in
> a bank-switched way.  And it is that whole VGA memory buffer which is
> `displayed' to (eg) vlc clients.

If you look closer, you'll find that s->vram_ptr actually points to an offset 
from phys_ram_base. So the VGA framebuffer is already saved by ram_save.

If the xen patches have changed this then you may need your patch. It has no 
business in mainstream qemu though.

Paul

WARNING: multiple messages have this Message-ID (diff)
From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: xen-devel@lists.xensource.com, Ian Jackson <Ian.Jackson@eu.citrix.com>
Subject: Re: [PATCH] ioemu/qemu vga: save and restore vram buffer (revised)
Date: Mon, 17 Dec 2007 16:22:11 +0000	[thread overview]
Message-ID: <200712171622.12475.paul@codesourcery.com> (raw)
In-Reply-To: <18278.23285.98750.687170@mariner.uk.xensource.com>

> In any case, vl.c's saving arrangements do save the buffer in
> phys_ram_base - but that isn't what the guest sees in the VGA memory

It doesn't matter what the guest physical mappings (if any) are.

> area.  The guest sees the vga memory-mapped IO registers (whose
> meaning _is_ generally saved by vga.c), plus it can use the VGA memory
> area and those control registers to access the whole of s->vram_ptr in
> a bank-switched way.  And it is that whole VGA memory buffer which is
> `displayed' to (eg) vlc clients.

If you look closer, you'll find that s->vram_ptr actually points to an offset 
from phys_ram_base. So the VGA framebuffer is already saved by ram_save.

If the xen patches have changed this then you may need your patch. It has no 
business in mainstream qemu though.

Paul

  reply	other threads:[~2007-12-17 16:23 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-12-10 18:14 [Qemu-devel] [PATCH] ioemu/qemu vga: save and restore vram buffer Ian Jackson
2007-12-10 18:14 ` Ian Jackson
2007-12-10 19:03 ` [Qemu-devel] " andrzej zaborowski
2007-12-10 19:03   ` andrzej zaborowski
2007-12-12 11:44   ` [Qemu-devel] [PATCH] ioemu/qemu vga: save and restore vram buffer (revised) Ian Jackson
2007-12-12 11:44     ` Ian Jackson
2007-12-16 11:35     ` [Qemu-devel] " andrzej zaborowski
2007-12-16 11:35       ` andrzej zaborowski
2007-12-17 11:18       ` [Qemu-devel] " Ian Jackson
     [not found]         ` <m2n.s.1JFvsr-002RPK@chiark.greenend.org.uk>
2007-12-17 16:22         ` Paul Brook [this message]
2007-12-17 16:22           ` Paul Brook
2007-12-17 18:25           ` [Qemu-devel] xen / qemu convergence ? Ian Jackson
2007-12-17 18:52             ` andrzej zaborowski
2007-12-17 18:52               ` andrzej zaborowski
2007-12-18 10:41               ` [Qemu-devel] " Ian Jackson
2007-12-17 18:55             ` Paul Brook
2007-12-17 18:55               ` Paul Brook
     [not found]     ` <m2n.s.1JFvre-002RW5@chiark.greenend.org.uk>
2008-01-21 11:41       ` Re: [Qemu-devel] [PATCH] ioemu/qemu vga: save and restore vram buffer (revised) Ian Jackson

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