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[Qemu-devel] Re: When should I use qemu_ram_alloc(), and how?
From: |
Blue Swirl |
Subject: |
[Qemu-devel] Re: When should I use qemu_ram_alloc(), and how? |
Date: |
Tue, 4 Nov 2008 21:14:47 +0200 |
On 11/4/08, address@hidden <address@hidden> wrote:
> Hi,
> # Reusing thread, to video memory allocation related question.
> Could you please give me answer to my question ?
>
> Attached diff is for adding cirrus_vga onto r2d, for explanatin.
> The point is here.
> - cpu_register_physical_memory(SDRAM_BASE, SDRAM_SIZE, 0);
> + r = qemu_ram_alloc(SDRAM_SIZE);
> + cpu_register_physical_memory(SDRAM_BASE, SDRAM_SIZE, r);
Well, I haven't been using qemu_ram_alloc on Sparc but instead used
direct offsets. Maybe I should convert. Also, all ram allocation
should be done using qemu_ram_alloc (especially system RAM), not just
some devices.
> Apparently, r2d had not used qemu_ram_alloc() (it is working, though).
> I added it here without knowing well about qemu memory system
> (this one is working fine, too).
>
> Maybe, allocation is needed always(even when without VGA), isn't it?
I don't think so, unallocated memory will be just unused.
> Are there any restriction between alloced address and register address?
> I am worried about it because PC seems to make them equal.
There are some code that assumes that CPU address for RAM can be
converted to host address using phys_ram_base + CPU address.
> - pci_register_io_region((PCIDevice *)d, 0, 0x2000000,
> + pci_register_io_region((PCIDevice *)d, 0, vga_ram_size,
To me this change looks OK, but I think it should be separate and the
PC folks should consider if it breaks something.
- Re: [Qemu-devel] [PATCH] SM501 emulation for R2D-SH4, (continued)
- Re: [Qemu-devel] [PATCH] SM501 emulation for R2D-SH4, andrzej zaborowski, 2008/11/01
- Re: [Qemu-devel] [PATCH] SM501 emulation for R2D-SH4, Blue Swirl, 2008/11/02
- Re: [Qemu-devel] [PATCH] SM501 emulation for R2D-SH4, Shin-ichiro KAWASAKI, 2008/11/04
- Re: [Qemu-devel] [PATCH] SM501 emulation for R2D-SH4, Blue Swirl, 2008/11/04
- [Qemu-devel] [PATCH] [RESEND] SM501 emulation for R2D-SH4, Shin-ichiro KAWASAKI, 2008/11/05
- Re: [Qemu-devel] [PATCH] [RESEND] SM501 emulation for R2D-SH4, Blue Swirl, 2008/11/05
- Re: [Qemu-devel] [PATCH] [RESEND] SM501 emulation for R2D-SH4, andrzej zaborowski, 2008/11/05
- Re: [Qemu-devel] [PATCH] [RESEND] SM501 emulation for R2D-SH4, Blue Swirl, 2008/11/05
[Qemu-devel] When should I use qemu_ram_alloc(), and how?, takasi-y, 2008/11/04