Re: [Qemu-devel] [PATCH] Compile dma only once

[Blue Swirl]

On Fri, May 28, 2010 at 7:34 PM, Paul Brook <address@hidden> wrote:
>> Use a qemu_irq to request CPU exit.
>
> Needing to request a CPU exit at all is just wrong. See previous discussions
> about how any use of qemu_bh_schedule_idle is fundamentally broken.

I agree for the device case. Is the attached patch then OK?

But what about other uses (with the patch applied):

User emulator signal delivery:
/src/qemu/darwin-user/signal.c:216:        cpu_exit(global_env);
/src/qemu/linux-user/signal.c:507:        cpu_exit(thread_env);

qemu_notify_event():
/src/qemu/cpus.c:286:        cpu_exit(env);
/src/qemu/cpus.c:289:        cpu_exit(next_cpu);
Is that broken too and should be removed?

cpu_signal():
/src/qemu/cpus.c:531:        cpu_exit(cpu_single_env);

vm_stop():
/src/qemu/cpus.c:733:            cpu_exit(cpu_single_env);

KVM IO window exit:
/src/qemu/kvm-all.c:859:            cpu_exit(env);

Some exclusive ARM operation:
/src/qemu/linux-user/main.c:152:            cpu_exit(other);

ARM/m68k semihosting:
/src/qemu/gdbstub.c:2296:    cpu_exit(s->c_cpu);

0001-dma-remove-DMA_schedule-and-related-cpu_request_exi.patch
Description: Source code patch