[Qemu-devel] Re: [PATCH v2 06/20] kvm: Install optimized interrupt handler

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

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On 2011-03-15 18:10, Marcelo Tosatti wrote:
> On Tue, Mar 15, 2011 at 12:26:17PM +0100, Jan Kiszka wrote:
>> KVM only requires to set the raised IRQ in CPUState and to kick the
>> receiving vcpu if it is remote.
>>
>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>> ---
>>  kvm-all.c |   11 +++++++++++
>>  1 files changed, 11 insertions(+), 0 deletions(-)
>>
>> diff --git a/kvm-all.c b/kvm-all.c
>> index 226843c..25ab545 100644
>> --- a/kvm-all.c
>> +++ b/kvm-all.c
>> @@ -650,6 +650,15 @@ 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 (!qemu_cpu_is_self(env)) {
>> +        qemu_cpu_kick(env);
>> +    }
>> +}
>> +
> 
> Not sure its worthwhile to allow different handlers. The advantage over
> tcg version is that its shorter, without cpu_unlink_tb and icount
> handler?

I thought about this again as well before posting, and I came to the
conclusion that an important advantage is avoiding TCG surprises in KVM
code paths. This way, KVM does not need to bother if cpu_unlink_tb or
icount related code changes. Maybe I should have added this to the
commit message.

Jan


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