Patchwork Current differences between qemu --enable-kvm and qemu-kvm?

login
register
mail settings
Submitter Gerd Hoffmann
Date May 22, 2012, 1:05 p.m.
Message ID <4FBB8F01.8090008@redhat.com>
Download mbox | patch
Permalink /patch/160630/
State New
Headers show

Comments

Gerd Hoffmann - May 22, 2012, 1:05 p.m.
Hi,

> BTW, if someone could have a look at the VGA diffs and resolve them,
> that would be great.

There isn't much ...


I think we should just make them large enougth that they are practically
unlimited.  Those are 16bit registers in virtual hardware.  Guess we
better leave the high bit clear to avoid possible issues with signed
integers.  So (1<<14) aka 16384 maybe?  Or 16000?

-#define VGA_RAM_SIZE (8192 * 1024)
+#define VGA_RAM_SIZE (16 * 1024 * 1024)

That one is more tricky as it breaks migration.  I guess qemu has to
stick to 8M by default for that reason.  We certainly can make the vga
memory size configurable via property though, so you can easily go for
16M or even more (or 1M to reduce the memory footprint of your guests
when using text mode only).

> Gerd, what's the state of switching the BIOS?

Postponed to 1.2.  Too risky for 1.1, also malc vetoed the switch
without seavgabios supporting the vesa protected mode interface which
still needs to be done.

cheers,
  Gerd

Patch

--- a/hw/vga_int.h
+++ b/hw/vga_int.h
@@ -31,8 +31,8 @@ 

-#define VBE_DISPI_MAX_XRES              1600
-#define VBE_DISPI_MAX_YRES              1200
+#define VBE_DISPI_MAX_XRES              2560
+#define VBE_DISPI_MAX_YRES              1600

The vgabios (both lgpl'ed and seavgabios) filters the mode list by
available memory anyway, so there is no need to keep those low enougth
that the xmax * ymax * 32bpp fits into vga memory.  And when the vgamem
becomes configurable (see below) this will be moot anyway.