Re: [Qemu-devel] [PATCH V5 2/4] target-i386:add coalesced_pio API

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Aug 31, 2018 at 05:05:03PM +0800, Peng Hao wrote:
> Signed-off-by: Peng Hao <peng.hao2@zte.com.cn>
> Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
>  accel/kvm/kvm-all.c   | 57 +++++++++++++++++++++++++++++++++++++++++++++++----
>  include/exec/memory.h |  4 ++--
>  memory.c              |  4 ++--
>  3 files changed, 57 insertions(+), 8 deletions(-)
> 
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index 4a3909d..11d8d78 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -78,6 +78,7 @@ struct KVMState
>      int fd;
>      int vmfd;
>      int coalesced_mmio;
> +    int coalesced_pio;
>      struct kvm_coalesced_mmio_ring *coalesced_mmio_ring;
>      bool coalesced_flush_in_progress;
>      int vcpu_events;
> @@ -559,6 +560,45 @@ static void kvm_uncoalesce_mmio_region(MemoryListener *listener,
>      }
>  }
>  
> +static void kvm_coalesce_pio_add(MemoryListener *listener,
> +                                MemoryRegionSection *section,
> +                                hwaddr start, hwaddr size)
> +{
> +    KVMState *s = kvm_state;
> +
> +    if (s->coalesced_pio) {
> +        struct kvm_coalesced_mmio_zone zone;
> +
> +        zone.addr = start;
> +        zone.size = size;
> +        zone.pio = 1;
> +
> +        (void)kvm_vm_ioctl(s, KVM_REGISTER_COALESCED_MMIO, &zone);
> +    }
> +}
> +
> +static void kvm_coalesce_pio_del(MemoryListener *listener,
> +                                MemoryRegionSection *section,
> +                                hwaddr start, hwaddr size)
> +{
> +    KVMState *s = kvm_state;
> +
> +    if (s->coalesced_pio) {
> +        struct kvm_coalesced_mmio_zone zone;
> +
> +        zone.addr = start;
> +        zone.size = size;
> +        zone.pio = 1;
> +
> +        (void)kvm_vm_ioctl(s, KVM_UNREGISTER_COALESCED_MMIO, &zone);
> +     }
> +}

assert rather than (void)?

> +
> +static MemoryListener kvm_coalesced_pio_listener = {
> +    .coalesced_io_add = kvm_coalesce_pio_add,
> +    .coalesced_io_del = kvm_coalesce_pio_del,
> +};
> +
>  int kvm_check_extension(KVMState *s, unsigned int extension)
>  {
>      int ret;
> @@ -1615,6 +1655,8 @@ static int kvm_init(MachineState *ms)
>      }
>  
>      s->coalesced_mmio = kvm_check_extension(s, KVM_CAP_COALESCED_MMIO);
> +    s->coalesced_pio = s->coalesced_mmio &&
> +                       kvm_check_extension(s, KVM_CAP_COALESCED_PIO);
>  
>  #ifdef KVM_CAP_VCPU_EVENTS
>      s->vcpu_events = kvm_check_extension(s, KVM_CAP_VCPU_EVENTS);
> @@ -1687,13 +1729,15 @@ static int kvm_init(MachineState *ms)
>          s->memory_listener.listener.eventfd_add = kvm_mem_ioeventfd_add;
>          s->memory_listener.listener.eventfd_del = kvm_mem_ioeventfd_del;
>      }
> -    s->memory_listener.listener.coalesced_mmio_add = kvm_coalesce_mmio_region;
> -    s->memory_listener.listener.coalesced_mmio_del = kvm_uncoalesce_mmio_region;
> +    s->memory_listener.listener.coalesced_io_add = kvm_coalesce_mmio_region;
> +    s->memory_listener.listener.coalesced_io_del = kvm_uncoalesce_mmio_region;
>  
>      kvm_memory_listener_register(s, &s->memory_listener,
>                                   &address_space_memory, 0);
>      memory_listener_register(&kvm_io_listener,
>                               &address_space_io);
> +    memory_listener_register(&kvm_coalesced_pio_listener,
> +                             &address_space_io);
>  
>      s->many_ioeventfds = kvm_check_many_ioeventfds();
>  
> @@ -1775,8 +1819,13 @@ void kvm_flush_coalesced_mmio_buffer(void)
>              struct kvm_coalesced_mmio *ent;
>  
>              ent = &ring->coalesced_mmio[ring->first];
> -
> -            cpu_physical_memory_write(ent->phys_addr, ent->data, ent->len);
> +            if (ent->pio == 1) {
> +                address_space_rw(&address_space_io, ent->phys_addr,
> +                                 MEMTXATTRS_UNSPECIFIED, ent->data,
> +                                 ent->len, true);
> +            } else {
> +                cpu_physical_memory_write(ent->phys_addr, ent->data, ent->len);
> +            }
>              smp_wmb();
>              ring->first = (ring->first + 1) % KVM_COALESCED_MMIO_MAX;
>          }
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index 448d41a..4600fa3 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -410,9 +410,9 @@ struct MemoryListener {
>                          bool match_data, uint64_t data, EventNotifier *e);
>      void (*eventfd_del)(MemoryListener *listener, MemoryRegionSection *section,
>                          bool match_data, uint64_t data, EventNotifier *e);
> -    void (*coalesced_mmio_add)(MemoryListener *listener, MemoryRegionSection *section,
> +    void (*coalesced_io_add)(MemoryListener *listener, MemoryRegionSection *section,
>                                 hwaddr addr, hwaddr len);
> -    void (*coalesced_mmio_del)(MemoryListener *listener, MemoryRegionSection *section,
> +    void (*coalesced_io_del)(MemoryListener *listener, MemoryRegionSection *section,
>                                 hwaddr addr, hwaddr len);
>      /* Lower = earlier (during add), later (during del) */
>      unsigned priority;
> diff --git a/memory.c b/memory.c
> index e9cd446..8b0311e 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -2126,7 +2126,7 @@ static void memory_region_update_coalesced_range_as(MemoryRegion *mr, AddressSpa
>                  .size = fr->addr.size,
>              };
>  
> -            MEMORY_LISTENER_CALL(as, coalesced_mmio_del, Reverse, &section,
> +            MEMORY_LISTENER_CALL(as, coalesced_io_del, Reverse, &section,
>                                   int128_get64(fr->addr.start),
>                                   int128_get64(fr->addr.size));
>              QTAILQ_FOREACH(cmr, &mr->coalesced, link) {
> @@ -2137,7 +2137,7 @@ static void memory_region_update_coalesced_range_as(MemoryRegion *mr, AddressSpa
>                      continue;
>                  }
>                  tmp = addrrange_intersection(tmp, fr->addr);
> -                MEMORY_LISTENER_CALL(as, coalesced_mmio_add, Forward, &section,
> +                MEMORY_LISTENER_CALL(as, coalesced_io_add, Forward, &section,
>                                       int128_get64(tmp.start),
>                                       int128_get64(tmp.size));
>              }
> -- 
> 1.8.3.1