Is KVM_GET_SREGS safe from other threads?

[Pekka Enberg <penberg@kernel.org>]

Hi!

We've noticed that sometimes KVM_GET_SREGS from a signal handler
hangs. We use it like this:

static void handle_sigquit(int sig)
{
         int i;

         for (i = 0; i < nrcpus; i++) {
                 struct kvm_cpu *cpu = kvm_cpus[i];

                 kvm_cpu__show_registers(cpu); <-- here
                 kvm_cpu__show_code(cpu);
                 kvm_cpu__show_page_tables(cpu);
         }

and

void kvm_cpu__show_registers(struct kvm_cpu *self)
{
[...]
	if (ioctl(self->vcpu_fd, KVM_GET_SREGS, &sregs) < 0)
		die("KVM_GET_REGS failed");

is it not OK to call KVM_GET_SREGS from other threads than the one
that's doing KVM_RUN?

                        Pekka