[Qemu-devel] Re: [PATCH 03/15] kvm: Install optimized interrupt handlers

[Jan Kiszka <jan.kiszka@web.de>]

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On 2011-03-05 16:37, Marcelo Tosatti wrote:
> On Fri, Mar 04, 2011 at 11:20:00AM +0100, Jan Kiszka wrote:
>> KVM only requires to set the raised IRQ in CPUState and, if the user
>> space irqchip is used, to kick the receiving vcpu if it is remote.
>>
>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>> ---
>>  kvm-all.c |   17 +++++++++++++++++
>>  1 files changed, 17 insertions(+), 0 deletions(-)
>>
>> diff --git a/kvm-all.c b/kvm-all.c
>> index 226843c..c460d45 100644
>> --- a/kvm-all.c
>> +++ b/kvm-all.c
>> @@ -650,6 +650,20 @@ static CPUPhysMemoryClient kvm_cpu_phys_memory_client = {
>>      .log_stop = kvm_log_stop,
>>  };
>>  
>> +static void kvm_handle_interrupt(CPUState *env, int mask)
>> +{
>> +    env->interrupt_request |= mask;
>> +
> 
> If the env->interrupt_request request is processed in userspace, such as
> MCE, the kick is still necessary for irqchip case. CPU_INTERRUPT_DEBUG
> is another example, no?

[this probably targeted kvm_handle_interrupt_kernel_irqchip]

In principle, you are right. But MCE must be injected synchronously over
the target VCPU, see do_inject_x86_mce, and CPU_INTERRUPT_DEBUG is also
synchronous and not even used in KVM mode.

> 
>> +    if (!qemu_cpu_self(env)) {
>> +        qemu_cpu_kick(env);
>> +    }
>> +}
>> +
>> +static void kvm_handle_interrupt_kernel_irqchip(CPUState *env, int mask)
>> +{
>> +    env->interrupt_request |= mask;
>> +}
>> +

Jan


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