Re: [Qemu-devel] [PATCH] KVM_CAP_IRQFD and KVM_CAP_IRQFD_RESAMPLE checks

[Eric Auger <eric.auger@linaro.org>]

On 09/01/2014 12:49 PM, Paolo Bonzini wrote:
> Il 29/08/2014 19:38, Eric Auger ha scritto:
>> Compute kvm_irqfds_allowed by checking the KVM_CAP_IRQFD extension.
>> Remove direct settings in architecture specific files.
>>
>> Add a new kvm_resamplefds_allowed variable, initialized by
>> checking the KVM_CAP_IRQFD_RESAMPLE extension. Add a corresponding
>> kvm_resamplefds_enabled() function.
> 
> Please add a user too (in hw/misc/vfio.c).

Hi Paolo,

OK sure. Thanks

Best Regards

Eric
> 
> Otherwise looks good, thanks!
> 
> Paolo
> 
>> Signed-off-by: Eric Auger <eric.auger@linaro.org>
>>
>> ---
>>
>> in practice KVM_CAP_IRQFD_RESAMPLE seems to be always enabled
>> as soon as kernel has HAVE_KVM_IRQFD so the resamplefd check
>> may be unnecessary.
>> ---
>>  hw/intc/openpic_kvm.c |  1 -
>>  hw/intc/xics_kvm.c    |  1 -
>>  include/sysemu/kvm.h  | 10 ++++++++++
>>  kvm-all.c             |  7 +++++++
>>  target-i386/kvm.c     |  1 -
>>  target-s390x/kvm.c    |  1 -
>>  6 files changed, 17 insertions(+), 4 deletions(-)
>>
>> diff --git a/hw/intc/openpic_kvm.c b/hw/intc/openpic_kvm.c
>> index e3bce04..6cef3b1 100644
>> --- a/hw/intc/openpic_kvm.c
>> +++ b/hw/intc/openpic_kvm.c
>> @@ -229,7 +229,6 @@ static void kvm_openpic_realize(DeviceState *dev, Error **errp)
>>          kvm_irqchip_add_irq_route(kvm_state, i, 0, i);
>>      }
>>  
>> -    kvm_irqfds_allowed = true;
>>      kvm_msi_via_irqfd_allowed = true;
>>      kvm_gsi_routing_allowed = true;
>>  
>> diff --git a/hw/intc/xics_kvm.c b/hw/intc/xics_kvm.c
>> index 20b19e9..c15453f 100644
>> --- a/hw/intc/xics_kvm.c
>> +++ b/hw/intc/xics_kvm.c
>> @@ -448,7 +448,6 @@ static void xics_kvm_realize(DeviceState *dev, Error **errp)
>>      }
>>  
>>      kvm_kernel_irqchip = true;
>> -    kvm_irqfds_allowed = true;
>>      kvm_msi_via_irqfd_allowed = true;
>>      kvm_gsi_direct_mapping = true;
>>  
>> diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
>> index 174ea36..69c4d0f 100644
>> --- a/include/sysemu/kvm.h
>> +++ b/include/sysemu/kvm.h
>> @@ -45,6 +45,7 @@ extern bool kvm_async_interrupts_allowed;
>>  extern bool kvm_halt_in_kernel_allowed;
>>  extern bool kvm_eventfds_allowed;
>>  extern bool kvm_irqfds_allowed;
>> +extern bool kvm_resamplefds_allowed;
>>  extern bool kvm_msi_via_irqfd_allowed;
>>  extern bool kvm_gsi_routing_allowed;
>>  extern bool kvm_gsi_direct_mapping;
>> @@ -102,6 +103,15 @@ extern bool kvm_readonly_mem_allowed;
>>  #define kvm_irqfds_enabled() (kvm_irqfds_allowed)
>>  
>>  /**
>> + * kvm_resamplefds_enabled:
>> + *
>> + * Returns: true if we can use resamplefds to inject interrupts into
>> + * a KVM CPU (ie the kernel supports resamplefds and we are running
>> + * with a configuration where it is meaningful to use them).
>> + */
>> +#define kvm_resamplefds_enabled() (kvm_resamplefds_allowed)
>> +
>> +/**
>>   * kvm_msi_via_irqfd_enabled:
>>   *
>>   * Returns: true if we can route a PCI MSI (Message Signaled Interrupt)
>> diff --git a/kvm-all.c b/kvm-all.c
>> index 1402f4f..fdc97d6 100644
>> --- a/kvm-all.c
>> +++ b/kvm-all.c
>> @@ -116,6 +116,7 @@ bool kvm_async_interrupts_allowed;
>>  bool kvm_halt_in_kernel_allowed;
>>  bool kvm_eventfds_allowed;
>>  bool kvm_irqfds_allowed;
>> +bool kvm_resamplefds_allowed;
>>  bool kvm_msi_via_irqfd_allowed;
>>  bool kvm_gsi_routing_allowed;
>>  bool kvm_gsi_direct_mapping;
>> @@ -1548,6 +1549,12 @@ int kvm_init(MachineClass *mc)
>>      kvm_eventfds_allowed =
>>          (kvm_check_extension(s, KVM_CAP_IOEVENTFD) > 0);
>>  
>> +    kvm_irqfds_allowed =
>> +        (kvm_check_extension(s, KVM_CAP_IRQFD) > 0);
>> +
>> +    kvm_resamplefds_allowed =
>> +        (kvm_check_extension(s, KVM_CAP_IRQFD_RESAMPLE) > 0);
>> +
>>      ret = kvm_arch_init(s);
>>      if (ret < 0) {
>>          goto err;
>> diff --git a/target-i386/kvm.c b/target-i386/kvm.c
>> index 097fe11..4bc2d80 100644
>> --- a/target-i386/kvm.c
>> +++ b/target-i386/kvm.c
>> @@ -2447,7 +2447,6 @@ void kvm_arch_init_irq_routing(KVMState *s)
>>       * irqchip, so we can use irqfds, and on x86 we know
>>       * we can use msi via irqfd and GSI routing.
>>       */
>> -    kvm_irqfds_allowed = true;
>>      kvm_msi_via_irqfd_allowed = true;
>>      kvm_gsi_routing_allowed = true;
>>  }
>> diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
>> index a32d91a..4d2bca6 100644
>> --- a/target-s390x/kvm.c
>> +++ b/target-s390x/kvm.c
>> @@ -1281,7 +1281,6 @@ void kvm_arch_init_irq_routing(KVMState *s)
>>       * have to override the common code kvm_halt_in_kernel_allowed setting.
>>       */
>>      if (kvm_check_extension(s, KVM_CAP_IRQ_ROUTING)) {
>> -        kvm_irqfds_allowed = true;
>>          kvm_gsi_routing_allowed = true;
>>          kvm_halt_in_kernel_allowed = false;
>>      }
>>
>