[Qemu-devel] Re: [PATCH 07/15] kvm: Separate TCG from KVM cpu execution

[Marcelo Tosatti <mtosatti@redhat.com>]

On Wed, Feb 09, 2011 at 08:59:23AM +0100, Jan Kiszka wrote:
> On 2011-02-09 00:39, Marcelo Tosatti wrote:
> > On Mon, Feb 07, 2011 at 12:19:18PM +0100, Jan Kiszka wrote:
> >> Mixing up TCG bits with KVM already led to problems around eflags
> >> emulation on x86. Moreover, quite some code that TCG requires on cpu
> >> enty/exit is useless for KVM. So dispatch between tcg_cpu_exec and
> >> kvm_cpu_exec as early as possible.
> >>
> >> The core logic of cpu_halted from cpu_exec is added to
> >> kvm_arch_process_irqchip_events. Moving away from cpu_exec makes
> >> exception_index meaningless for KVM, we can simply pass the exit reason
> >> directly (only "EXCP_DEBUG vs. rest" is relevant).
> >>
> >> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> >> ---
> >>  cpu-exec.c        |   19 ++++++-------------
> >>  cpus.c            |   10 +++++-----
> >>  kvm-all.c         |   19 +++++++++----------
> >>  target-i386/kvm.c |    6 +++---
> >>  4 files changed, 23 insertions(+), 31 deletions(-)
> >>
> >> diff --git a/target-i386/kvm.c b/target-i386/kvm.c
> >> index ba183c4..377a0a3 100644
> >> --- a/target-i386/kvm.c
> >> +++ b/target-i386/kvm.c
> >> @@ -1502,12 +1502,13 @@ int kvm_arch_post_run(CPUState *env, struct kvm_run *run)
> >>  
> >>  int kvm_arch_process_irqchip_events(CPUState *env)
> >>  {
> >> +    if (env->interrupt_request & (CPU_INTERRUPT_HARD | CPU_INTERRUPT_NMI)) {
> >> +        env->halted = 0;
> >> +    }
> > 
> > Why is it necessary to clear env->halted here?
> 
> Because we no longer come along cpu_halted() in cpu_exec(). This
> corresponds to the tail of process_irqchip_events() in qemu-kvm

This is not yet well integrated, we probably don't need env->halted
anymore (see cpu_has_work). Can be improved later though.