Re: [Qemu-devel] [PATCH 3/3] Add KVM support to QEMU

Hollis Blanchard
2008-10-28T20:49:31Z

Just a quick skim...

On Tue, Oct 28, 2008 at 3:13 PM, Anthony Liguori <aliguori@us.ibm.com> wrote:
> +int kvm_cpu_exec(CPUState *env)
> +{
> + struct kvm_run *run = env->kvm_run;
> + int ret;
> +
> + dprintf("kvm_cpu_exec()\n");
> +
> + do {
> + kvm_arch_pre_run(env, run);
> +
> + if ((env->interrupt_request & CPU_INTERRUPT_EXIT)) {
> + dprintf("interrupt exit requested\n");
> + ret = 0;
> + break;
> + }
> +
> + dprintf("setting tpr\n");
> + run->cr8 = cpu_get_apic_tpr(env);

This belongs in the arch_pre_run hook above.

> + ret = kvm_vcpu_ioctl(env, KVM_RUN, 0);
> + kvm_arch_post_run(env, run);
> +
> + if (ret == -EINTR || ret == -EAGAIN) {
> + dprintf("io window exit\n");
> + ret = 0;
> + break;
> + }
> +
> + if (ret < 0) {
> + dprintf("kvm run failed %s\n", strerror(-ret));
> + abort();
> + }
> +
> + ret = 0; /* exit loop */
> + switch (run->exit_reason) {
> + case KVM_EXIT_IO:
> + dprintf("handle_io\n");
> + ret = kvm_handle_io(env, run->io.port,
> + (uint8_t *)run + run->io.data_offset,
> + run->io.direction,
> + run->io.size,
> + run->io.count);
> + break;
> + case KVM_EXIT_MMIO:
> + dprintf("handle_mmio\n");
> + cpu_physical_memory_rw(run->mmio.phys_addr,
> + run->mmio.data,
> + run->mmio.len,
> + run->mmio.is_write);
> + ret = 1;
> + break;
> + case KVM_EXIT_IRQ_WINDOW_OPEN:
> + dprintf("irq_window_open\n");
> + break;
> + case KVM_EXIT_SHUTDOWN:
> + dprintf("shutdown\n");
> + qemu_system_reset_request();
> + ret = 1;
> + break;
> + case KVM_EXIT_UNKNOWN:
> + dprintf("kvm_exit_unknown\n");
> + break;
> + case KVM_EXIT_FAIL_ENTRY:
> + dprintf("kvm_exit_fail_entry\n");
> + break;
> + case KVM_EXIT_EXCEPTION:
> + dprintf("kvm_exit_exception\n");
> + break;
> + case KVM_EXIT_DEBUG:
> + dprintf("kvm_exit_debug\n");
> + break;
> + default:
> + dprintf("kvm_arch_handle_exit\n");
> + ret = kvm_arch_handle_exit(env, run);
> + break;
> + }
> + } while (ret > 0);
> +
> + return ret;
> +}

How did you decide which exit handlers should go into
architecture-specific code? Looking at just the KVM architecture set:
IO: x86 and ia64, not PowerPC or s390
MMIO: everybody except s390
DCRs: PowerPC only
IRQ window: not sure

-Hollis