Re: [Qemu-devel] [RESEND PATCH v16 3/6] kvm-all.c: add qemu_irq/gsi hash table and utility routines

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

Hi Peter,

On 06/26/2015 01:41 PM, Peter Maydell wrote:
> On 15 June 2015 at 17:33, Eric Auger <eric.auger@linaro.org> wrote:
>> VFIO platform device needs to setup irqfd but it does not know the
>> gsi corresponding to the device qemu_irq. This series proposes to
>> store a hash table in kvm_state using the qemu_irq as key and the gsi
>> as a value.
>>
>> kvm_irqchip_set_qemuirq_gsi allows to insert such a pair. The interrupt
>> controller is supposed to use it.
>>
>> kvm_irqchip_[add, remove]_irqfd_notifier allows to setup/tear down
>> irqfd directly from the qemu_irq.
>>
>> Signed-off-by: Eric Auger <eric.auger@linaro.org>
>> Tested-by: Vikram Sethi <vikrams@codeaurora.org>
>>
>> ---
>>
>> v15 -> v16:
>> - Added Vikram's T-b
>>
>> v13 -> v14:
>> - correct checkpatch warning
>>
>> v2 -> v3 (integration into VFIO series v13):
>> - rename kvm_irqchip_[add, remove]_qemuirq_irqfd_notifier into
>>   kvm_irqchip_[add, remove]_irqfd_notifier. Possible since legacy
>>   functions were also renamed with _gsi suffix.
>>
>> V1 -> v2:
>> - qemu_irq get_gsi callback replaced by hash table stored in kvm
>> ---
>>  include/sysemu/kvm.h |  6 ++++++
>>  kvm-all.c            | 37 +++++++++++++++++++++++++++++++++++++
>>  2 files changed, 43 insertions(+)
>>
>> diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
>> index acb3025..ba612fc 100644
>> --- a/include/sysemu/kvm.h
>> +++ b/include/sysemu/kvm.h
>> @@ -19,6 +19,7 @@
>>  #include "qemu/queue.h"
>>  #include "qom/cpu.h"
>>  #include "exec/memattrs.h"
>> +#include "hw/irq.h"
>>
>>  #ifdef CONFIG_KVM
>>  #include <linux/kvm.h>
>> @@ -420,6 +421,11 @@ int kvm_irqchip_add_irqfd_notifier_gsi(KVMState *s, EventNotifier *n,
>>                                         EventNotifier *rn, int virq);
>>  int kvm_irqchip_remove_irqfd_notifier_gsi(KVMState *s, EventNotifier *n,
>>                                            int virq);
>> +int kvm_irqchip_add_irqfd_notifier(KVMState *s, EventNotifier *n,
>> +                                   EventNotifier *rn, qemu_irq irq);
>> +int kvm_irqchip_remove_irqfd_notifier(KVMState *s, EventNotifier *n,
>> +                                      qemu_irq irq);
>> +void kvm_irqchip_set_qemuirq_gsi(KVMState *s, qemu_irq irq, int gsi);
>>  void kvm_pc_gsi_handler(void *opaque, int n, int level);
>>  void kvm_pc_setup_irq_routing(bool pci_enabled);
>>  void kvm_init_irq_routing(KVMState *s);
>> diff --git a/kvm-all.c b/kvm-all.c
>> index 730b818..939bfc4 100644
>> --- a/kvm-all.c
>> +++ b/kvm-all.c
>> @@ -37,6 +37,7 @@
>>  #include "exec/address-spaces.h"
>>  #include "qemu/event_notifier.h"
>>  #include "trace.h"
>> +#include "hw/irq.h"
>>
>>  #include "hw/boards.h"
>>
>> @@ -98,6 +99,7 @@ struct KVMState
>>       * unsigned, and treating them as signed here can break things */
>>      unsigned irq_set_ioctl;
>>      unsigned int sigmask_len;
>> +    GHashTable *gsimap;
>>  #ifdef KVM_CAP_IRQ_ROUTING
>>      struct kvm_irq_routing *irq_routes;
>>      int nr_allocated_irq_routes;
>> @@ -1339,6 +1341,39 @@ int kvm_irqchip_remove_irqfd_notifier_gsi(KVMState *s, EventNotifier *n,
>>             false);
>>  }
>>
>> +int kvm_irqchip_add_irqfd_notifier(KVMState *s, EventNotifier *n,
>> +                                   EventNotifier *rn, qemu_irq irq)
>> +{
>> +    gpointer key, gsi;
>> +    gboolean found = g_hash_table_lookup_extended(s->gsimap, irq, &key, &gsi);
>> +
>> +    if (!found) {
>> +        return -ENXIO;
>> +    } else {
>> +        return kvm_irqchip_add_irqfd_notifier_gsi(s, n, rn,
>> +                                                  GPOINTER_TO_UINT(gsi));
> 
> Why do we use GPOINTER_TO_UINT() here...
Hum yes GPOINTER_TO_INT is in accordance with
kvm_irqchip_add_irqfd_notifier_gsi signature
> 
> 
>> +    }
>> +}
>> +
>> +int kvm_irqchip_remove_irqfd_notifier(KVMState *s, EventNotifier *n,
>> +                                      qemu_irq irq)
>> +{
>> +    gpointer key, gsi;
>> +    gboolean found = g_hash_table_lookup_extended(s->gsimap, irq, &key, &gsi);
>> +
>> +    if (!found) {
>> +        return -ENXIO;
>> +    } else {
>> +        return kvm_irqchip_remove_irqfd_notifier_gsi(s, n,
>> +                                                     GPOINTER_TO_INT(gsi));
> 
> ...but GPOINTER_TO_INT() here?

> 
> (Aside: you don't need to put this code in an else {} clause, because
> the if() part is returning anyway.)
Indeed.

Do you wish I re-submit all the VFIO remaining patches as v17 or only
that one?

Thanks

Eric
> 
>> +    }
>> +}
>> +
>> +void kvm_irqchip_set_qemuirq_gsi(KVMState *s, qemu_irq irq, int gsi)
>> +{
>> +    g_hash_table_insert(s->gsimap, irq, GINT_TO_POINTER(gsi));
>> +}
>> +
>>  static int kvm_irqchip_create(MachineState *machine, KVMState *s)
>>  {
>>      int ret;
>> @@ -1371,6 +1406,8 @@ static int kvm_irqchip_create(MachineState *machine, KVMState *s)
>>
>>      kvm_init_irq_routing(s);
>>
>> +    s->gsimap = g_hash_table_new(g_direct_hash, g_direct_equal);
>> +
>>      return 0;
>>  }
> 
> thanks
> -- PMM
>