Re: [Xen-devel] Unable to get QXL vga working

[ZhouPeng <zpengxen@xxxxxxxxx>]

On Thu, May 24, 2012 at 6:13 PM, Stefano Stabellini
<stefano.stabellini@xxxxxxxxxxxxx> wrote:
> On Thu, 24 May 2012, ZhouPeng wrote:
>> Sorry for late reply, I am not on this mail these days because of my work.
>>
>> I further test qxl-vga and I think I figure out the problem in some extend.
>>
>> If using qxl device, the default memory size of vga is 64M.
>> Which will cause xen_ram_alloc(qemu/xen-all.c) fails.
>>
>> The exact reason is xc_domain_populate_physmap_exact fails, because
>> xen-hypervisor
>> fail,
>> it's because of   alloc_domheap_pages(d, a->extent_order, a->memflags)
>> fails in hypervisor.
>>
>> I am not very familiar with xen's memory management, Does 64M exceed
>> xen's heap space in this context?
>
> XL sets an upper bound of memory that can be allocated to the VM in
> libxl__build_pre, calling xc_domain_setmaxmem.
> My guess is that a 64MB allocation would go over that limit.
> You could try increasing the limit manually changing the
> xc_domain_setmaxmem call in libxl__build_pre, or you could try setting
> videoram=64 in the VM config file.

Your guess is absolutely right!

But set videoram=128 or
xc_domain_setmaxmem(ctx->xch, domid, info->target_memkb +
LIBXL_MAXMEM_CONSTANT + 2 * 64 * 1024);

Then I successfuly install qxl driver in win-hvm and QXL can work properly.

I will send some patch to add qxl support to libxl.
-- 
Zhou Peng

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