Can legacy vga memory base address be defined different with architectures

Can legacy vga memory base address be defined different with architectures

[maobibo]

Hi Philippe,

    In file include/hw/pci/pci.h, the macro QEMU_PCI_VGA_MEM_BASE is defined as 0xa0000, which represents legacy VGA memory base address. I want to know whether it should be the same for all architectures, or does this vga mmio space exist on arm64/riscv physical machines with pci host bridges?

    I ask this question because it collapses with low ddr memory space on Loongarch, we want to low addr memory space is continuous.

regards
bibo, mao 

Re: Can legacy vga memory base address be defined different with architectures

[Richard Henderson]

On 6/28/22 12:12, maobibo wrote:
> Hi Philippe,
> 
>      In file include/hw/pci/pci.h, the macro QEMU_PCI_VGA_MEM_BASE is defined as 0xa0000, which represents legacy VGA memory base address. I want to know whether it should be the same for all architectures, or does this vga mmio space exist on arm64/riscv physical machines with pci host bridges?

This is x86 only.


r~

Re: Can legacy vga memory base address be defined different with architectures

[maobibo]

在 2022/6/28 16:21, Richard Henderson 写道:
> On 6/28/22 12:12, maobibo wrote:
>> Hi Philippe,
>>
>>      In file include/hw/pci/pci.h, the macro QEMU_PCI_VGA_MEM_BASE is defined as 0xa0000, which represents legacy VGA memory base address. I want to know whether it should be the same for all architectures, or does this vga mmio space exist on arm64/riscv physical machines with pci host bridges?
> 
> This is x86 only.

I see. On aarch64 virt platform, "virtio-gpu-pci" video card is used rather than "virtio-vga", there is no such legacy pci vga memory space with "virtio-gpu-pci" video card. I will check code, and thanks for your explanation. 

regards
bibo, mao 
> 
> 
> r~