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

[Peter Maydell]

On 15 June 2015 at 17:33, Eric Auger <address@hidden> 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 <address@hidden>
> Tested-by: Vikram Sethi <address@hidden>
>
> ---
>
> 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...


> +    }
> +}
> +
> +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.)

> +    }
> +}
> +
> +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