Re: [Qemu-discuss] vga through qemu in arm

[Alberto Garcia]

On Mon, May 14, 2018 at 02:40:42PM +0800, lizhuoyao wrote:
> hi everyone:
>   currently, I meet a problem about qemu.Use virt-install order to create a 
> domain, return a failed:
>   order: virt-install -n centos-gg -r 1024 --disk 
> centos-gg.img,format=qcow2,size=10 --cdrom 
> /home/Centos-7-aarch64-Everything.iso --graphics vnc, listen=0.0.0.0
> failed: this QEMU does not support 'cirrus' video device

Can you try with '--video=vga' ?

Berto

Re: [Qemu-discuss] Understanding the return value of the function tcg_qemu_tb_exec()

[Peter Maydell]

On 15 May 2018 at 22:09, Arnabjyoti Kalita  wrote:
> I was trying to understand what the function tcg_qemu_tb_exec() returns. I
> can understand that the last two bits of the return value contain the exit
> status of the translation block that just got executed. However I cannot
> understand what the remaining bits in the value point to. I find it hard to
> understand what it returns from the source code.
>
> Basically, I am finding it hard to determine if this function returns the
> current TB that was executed or that it returns the next TB that is to be
> executed.

That depends on the value in the bottom two bits. If the bottom two
bits are 2 or 3, then the pointer part is the TB we were about to
execute but abandoned execution of. If the bottom two bits are 0 or 1,
then the return value is whatever we passed to tcg_gen_exit_tb()
when we were generating the code for the exit path for the TB we
just executed. The pointer part will either be 0, or the address
of that just-executed TB. (We use this to try to link the
just-executed TB to the next one, so 0 means "don't try to link".)

thanks
-- PMM

Re: [Qemu-discuss] Understanding the return value of the function tcg_qemu_tb_exec()

[Arnabjyoti Kalita]

Hi Peter,

Thanks for highlighting this.

Regards,
Arnabjyoti Kalita

On Wed, May 16, 2018 at 9:14 AM, Peter Maydell 
wrote:

> On 15 May 2018 at 22:09, Arnabjyoti Kalita 
> wrote:
> > I was trying to understand what the function tcg_qemu_tb_exec() returns.
> I
> > can understand that the last two bits of the return value contain the
> exit
> > status of the translation block that just got executed. However I cannot
> > understand what the remaining bits in the value point to. I find it hard
> to
> > understand what it returns from the source code.
> >
> > Basically, I am finding it hard to determine if this function returns the
> > current TB that was executed or that it returns the next TB that is to be
> > executed.
>
> That depends on the value in the bottom two bits. If the bottom two
> bits are 2 or 3, then the pointer part is the TB we were about to
> execute but abandoned execution of. If the bottom two bits are 0 or 1,
> then the return value is whatever we passed to tcg_gen_exit_tb()
> when we were generating the code for the exit path for the TB we
> just executed. The pointer part will either be 0, or the address
> of that just-executed TB. (We use this to try to link the
> just-executed TB to the next one, so 0 means "don't try to link".)
>
> thanks
> -- PMM
>