Patchwork [v2] ivshmem: add a new PIO BAR3(Doorbell) besides MMIO BAR0 to reduce notification time

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Submitter zanghongyong@huawei.com
Date Nov. 18, 2011, 5:50 a.m.
Message ID <1321595404-2127-1-git-send-email-zanghongyong@huawei.com>
Download mbox | patch
Permalink /patch/126349/
State New
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Comments

zanghongyong@huawei.com - Nov. 18, 2011, 5:50 a.m.
From: Hongyong Zang <zanghongyong@huawei.com>

This patch, adds a PIO BAR3 for guest notifying qemu. And we find the new notification way of PIO BAR3 reduces 30% time in comparison with the original MMIO BAR0 way.

Signed-off-by: Hongyong Zang <zanghongyong@huawei.com>
---
 hw/ivshmem.c |   24 ++++++++++++++++++++++--
 kvm-all.c    |   23 +++++++++++++++++++++++
 kvm.h        |    1 +
 3 files changed, 46 insertions(+), 2 deletions(-)
Avi Kivity - Nov. 20, 2011, 9:27 a.m.
On 11/18/2011 07:50 AM, zanghongyong@huawei.com wrote:
> From: Hongyong Zang <zanghongyong@huawei.com>
>
> This patch, adds a PIO BAR3 for guest notifying qemu. And we find the new notification way of PIO BAR3 reduces 30% time in comparison with the original MMIO BAR0 way.

Please update the spec, and split the patch into an infrastructure patch
(for long eventfds in the memory API) and an ivshmem patch.

>  
>  //#define DEBUG_IVSHMEM
>  #ifdef DEBUG_IVSHMEM
> @@ -57,8 +58,10 @@ typedef struct IVShmemState {
>      CharDriverState **eventfd_chr;
>      CharDriverState *server_chr;
>      MemoryRegion ivshmem_mmio;
> +    MemoryRegion ivshmem_pio;
>  
>      pcibus_t mmio_addr;
> +    pcibus_t pio_addr;
>      /* We might need to register the BAR before we actually have the memory.
>       * So prepare a container MemoryRegion for the BAR immediately and
>       * add a subregion when we have the memory.
> @@ -234,7 +237,7 @@ static uint64_t ivshmem_io_read(void *opaque, target_phys_addr_t addr,
>      return ret;
>  }
>  
> -static const MemoryRegionOps ivshmem_mmio_ops = {
> +static const MemoryRegionOps ivshmem_io_ops = {
>      .read = ivshmem_io_read,
>      .write = ivshmem_io_write,
>      .endianness = DEVICE_NATIVE_ENDIAN,
> @@ -348,6 +351,8 @@ static void close_guest_eventfds(IVShmemState *s, int posn)
>      for (i = 0; i < guest_curr_max; i++) {
>          kvm_set_ioeventfd_mmio_long(s->peers[posn].eventfds[i],
>                      s->mmio_addr + DOORBELL, (posn << 16) | i, 0);
> +        kvm_set_ioeventfd_pio_long(s->peers[posn].eventfds[i],
> +                    s->pio_addr + DOORBELL, (posn << 16) | i, 0);

This really shouldn't be needed - the memory API should take care of it.

>          close(s->peers[posn].eventfds[i]);
>      }
>  
> @@ -367,6 +372,12 @@ static void setup_ioeventfds(IVShmemState *s) {
>                                        true,
>                                        (i << 16) | j,
>                                        s->peers[i].eventfds[j]);
> +            memory_region_add_eventfd(&s->ivshmem_pio,
> +                                      DOORBELL,
> +                                      4,
> +                                      true,
> +                                      (i << 16) | j,
> +                                      s->peers[i].eventfds[j]);
>          }
>      }

Where is the memory API support for this?

>  }
> @@ -495,6 +506,10 @@ static void ivshmem_read(void *opaque, const uint8_t * buf, int flags)
>                          (incoming_posn << 16) | guest_max_eventfd, 1) < 0) {
>              fprintf(stderr, "ivshmem: ioeventfd not available\n");
>          }
> +        if (kvm_set_ioeventfd_pio_long(incoming_fd, s->pio_addr + DOORBELL,
> +                        (incoming_posn << 16) | guest_max_eventfd, 1) < 0) {
> +            fprintf(stderr, "ivshmem: ioeventfd not available\n");
> +        }
>      }

Nor should this be needed.

Please make BAR 3 disappear if started with -M pc-1.0.
Cam Macdonell - Nov. 29, 2011, 6:38 a.m.
On Thu, Nov 17, 2011 at 10:50 PM,  <zanghongyong@huawei.com> wrote:
> From: Hongyong Zang <zanghongyong@huawei.com>
>
> This patch, adds a PIO BAR3 for guest notifying qemu. And we find the new notification way of PIO BAR3 reduces 30% time in comparison with the original MMIO BAR0 way.

Come to think of it, should we bump the PIO to BAR4 so that the shared
memory region could be made a 64-bit BAR and therefore take up BAR2
and BAR3?

>
> Signed-off-by: Hongyong Zang <zanghongyong@huawei.com>
> ---
>  hw/ivshmem.c |   24 ++++++++++++++++++++++--
>  kvm-all.c    |   23 +++++++++++++++++++++++
>  kvm.h        |    1 +
>  3 files changed, 46 insertions(+), 2 deletions(-)
>
> diff --git a/hw/ivshmem.c b/hw/ivshmem.c
> index 242fbea..031cdd8 100644
> --- a/hw/ivshmem.c
> +++ b/hw/ivshmem.c
> @@ -29,6 +29,7 @@
>  #define IVSHMEM_MASTER  1
>
>  #define IVSHMEM_REG_BAR_SIZE 0x100
> +#define IVSHIO_REG_BAR_SIZE 0x10
>
>  //#define DEBUG_IVSHMEM
>  #ifdef DEBUG_IVSHMEM
> @@ -57,8 +58,10 @@ typedef struct IVShmemState {
>     CharDriverState **eventfd_chr;
>     CharDriverState *server_chr;
>     MemoryRegion ivshmem_mmio;
> +    MemoryRegion ivshmem_pio;
>
>     pcibus_t mmio_addr;
> +    pcibus_t pio_addr;
>     /* We might need to register the BAR before we actually have the memory.
>      * So prepare a container MemoryRegion for the BAR immediately and
>      * add a subregion when we have the memory.
> @@ -234,7 +237,7 @@ static uint64_t ivshmem_io_read(void *opaque, target_phys_addr_t addr,
>     return ret;
>  }
>
> -static const MemoryRegionOps ivshmem_mmio_ops = {
> +static const MemoryRegionOps ivshmem_io_ops = {
>     .read = ivshmem_io_read,
>     .write = ivshmem_io_write,
>     .endianness = DEVICE_NATIVE_ENDIAN,
> @@ -348,6 +351,8 @@ static void close_guest_eventfds(IVShmemState *s, int posn)
>     for (i = 0; i < guest_curr_max; i++) {
>         kvm_set_ioeventfd_mmio_long(s->peers[posn].eventfds[i],
>                     s->mmio_addr + DOORBELL, (posn << 16) | i, 0);
> +        kvm_set_ioeventfd_pio_long(s->peers[posn].eventfds[i],
> +                    s->pio_addr + DOORBELL, (posn << 16) | i, 0);
>         close(s->peers[posn].eventfds[i]);
>     }
>
> @@ -367,6 +372,12 @@ static void setup_ioeventfds(IVShmemState *s) {
>                                       true,
>                                       (i << 16) | j,
>                                       s->peers[i].eventfds[j]);
> +            memory_region_add_eventfd(&s->ivshmem_pio,
> +                                      DOORBELL,
> +                                      4,
> +                                      true,
> +                                      (i << 16) | j,
> +                                      s->peers[i].eventfds[j]);
>         }
>     }
>  }
> @@ -495,6 +506,10 @@ static void ivshmem_read(void *opaque, const uint8_t * buf, int flags)
>                         (incoming_posn << 16) | guest_max_eventfd, 1) < 0) {
>             fprintf(stderr, "ivshmem: ioeventfd not available\n");
>         }
> +        if (kvm_set_ioeventfd_pio_long(incoming_fd, s->pio_addr + DOORBELL,
> +                        (incoming_posn << 16) | guest_max_eventfd, 1) < 0) {
> +            fprintf(stderr, "ivshmem: ioeventfd not available\n");
> +        }
>     }
>
>     return;
> @@ -656,8 +671,10 @@ static int pci_ivshmem_init(PCIDevice *dev)
>
>     s->shm_fd = 0;
>
> -    memory_region_init_io(&s->ivshmem_mmio, &ivshmem_mmio_ops, s,
> +    memory_region_init_io(&s->ivshmem_mmio, &ivshmem_io_ops, s,
>                           "ivshmem-mmio", IVSHMEM_REG_BAR_SIZE);
> +    memory_region_init_io(&s->ivshmem_pio, &ivshmem_io_ops, s,
> +                          "ivshmem-pio", IVSHIO_REG_BAR_SIZE);
>
>     if (ivshmem_has_feature(s, IVSHMEM_IOEVENTFD)) {
>         setup_ioeventfds(s);
> @@ -666,6 +683,8 @@ static int pci_ivshmem_init(PCIDevice *dev)
>     /* region for registers*/
>     pci_register_bar(&s->dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY,
>                      &s->ivshmem_mmio);
> +    pci_register_bar(&s->dev, 3, PCI_BASE_ADDRESS_SPACE_IO,
> +                     &s->ivshmem_pio);
>
>     memory_region_init(&s->bar, "ivshmem-bar2-container", s->ivshmem_size);
>
> @@ -742,6 +761,7 @@ static int pci_ivshmem_uninit(PCIDevice *dev)
>     IVShmemState *s = DO_UPCAST(IVShmemState, dev, dev);
>
>     memory_region_destroy(&s->ivshmem_mmio);
> +    memory_region_destroy(&s->ivshmem_pio);
>     memory_region_del_subregion(&s->bar, &s->ivshmem);
>     memory_region_destroy(&s->ivshmem);
>     memory_region_destroy(&s->bar);
> diff --git a/kvm-all.c b/kvm-all.c
> index 5d500e1..737c2e2 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -1396,6 +1396,29 @@ int kvm_set_ioeventfd_mmio_long(int fd, uint32_t addr, uint32_t val, bool assign
>     return 0;
>  }
>
> +int kvm_set_ioeventfd_pio_long(int fd, uint32_t addr, uint32_t val, bool assign)
> +{
> +    struct kvm_ioeventfd kick = {
> +        .datamatch = val,
> +        .addr = addr,
> +        .len = 4,
> +        .flags = KVM_IOEVENTFD_FLAG_DATAMATCH | KVM_IOEVENTFD_FLAG_PIO,
> +        .fd = fd,
> +    };
> +    int r;
> +    if (!kvm_enabled()) {
> +        return -ENOSYS;
> +    }
> +    if (!assign) {
> +        kick.flags |= KVM_IOEVENTFD_FLAG_DEASSIGN;
> +    }
> +    r = kvm_vm_ioctl(kvm_state, KVM_IOEVENTFD, &kick);
> +    if (r < 0) {
> +        return r;
> +    }
> +    return 0;
> +}
> +
>  int kvm_set_ioeventfd_pio_word(int fd, uint16_t addr, uint16_t val, bool assign)
>  {
>     struct kvm_ioeventfd kick = {
> diff --git a/kvm.h b/kvm.h
> index b15e1dd..c2373c9 100644
> --- a/kvm.h
> +++ b/kvm.h
> @@ -198,6 +198,7 @@ int kvm_set_ioeventfd_mmio_long(int fd, uint32_t adr, uint32_t val, bool assign)
>
>  int kvm_set_irqfd(int gsi, int fd, bool assigned);
>
> +int kvm_set_ioeventfd_pio_long(int fd, uint32_t adr, uint32_t val, bool assign);
>  int kvm_set_ioeventfd_pio_word(int fd, uint16_t adr, uint16_t val, bool assign);
>
>  typedef struct KVMMsiMessage {
> --
> 1.7.1
>
zanghongyong@huawei.com - Nov. 29, 2011, 7:02 a.m.
于 2011/11/29,星期二 14:38, Cam Macdonell 写道:
> On Thu, Nov 17, 2011 at 10:50 PM,<zanghongyong@huawei.com>  wrote:
>> From: Hongyong Zang<zanghongyong@huawei.com>
>>
>> This patch, adds a PIO BAR3 for guest notifying qemu. And we find the new notification way of PIO BAR3 reduces 30% time in comparison with the original MMIO BAR0 way.
> Come to think of it, should we bump the PIO to BAR4 so that the shared
> memory region could be made a 64-bit BAR and therefore take up BAR2
> and BAR3?
OK. The PIO BAR can be placed on BAR4. We'll finish the patch later.

Regards,
Hongyong
>> Signed-off-by: Hongyong Zang<zanghongyong@huawei.com>
>> ---
>>   hw/ivshmem.c |   24 ++++++++++++++++++++++--
>>   kvm-all.c    |   23 +++++++++++++++++++++++
>>   kvm.h        |    1 +
>>   3 files changed, 46 insertions(+), 2 deletions(-)
>>
>> diff --git a/hw/ivshmem.c b/hw/ivshmem.c
>> index 242fbea..031cdd8 100644
>> --- a/hw/ivshmem.c
>> +++ b/hw/ivshmem.c
>> @@ -29,6 +29,7 @@
>>   #define IVSHMEM_MASTER  1
>>
>>   #define IVSHMEM_REG_BAR_SIZE 0x100
>> +#define IVSHIO_REG_BAR_SIZE 0x10
>>
>>   //#define DEBUG_IVSHMEM
>>   #ifdef DEBUG_IVSHMEM
>> @@ -57,8 +58,10 @@ typedef struct IVShmemState {
>>      CharDriverState **eventfd_chr;
>>      CharDriverState *server_chr;
>>      MemoryRegion ivshmem_mmio;
>> +    MemoryRegion ivshmem_pio;
>>
>>      pcibus_t mmio_addr;
>> +    pcibus_t pio_addr;
>>      /* We might need to register the BAR before we actually have the memory.
>>       * So prepare a container MemoryRegion for the BAR immediately and
>>       * add a subregion when we have the memory.
>> @@ -234,7 +237,7 @@ static uint64_t ivshmem_io_read(void *opaque, target_phys_addr_t addr,
>>      return ret;
>>   }
>>
>> -static const MemoryRegionOps ivshmem_mmio_ops = {
>> +static const MemoryRegionOps ivshmem_io_ops = {
>>      .read = ivshmem_io_read,
>>      .write = ivshmem_io_write,
>>      .endianness = DEVICE_NATIVE_ENDIAN,
>> @@ -348,6 +351,8 @@ static void close_guest_eventfds(IVShmemState *s, int posn)
>>      for (i = 0; i<  guest_curr_max; i++) {
>>          kvm_set_ioeventfd_mmio_long(s->peers[posn].eventfds[i],
>>                      s->mmio_addr + DOORBELL, (posn<<  16) | i, 0);
>> +        kvm_set_ioeventfd_pio_long(s->peers[posn].eventfds[i],
>> +                    s->pio_addr + DOORBELL, (posn<<  16) | i, 0);
>>          close(s->peers[posn].eventfds[i]);
>>      }
>>
>> @@ -367,6 +372,12 @@ static void setup_ioeventfds(IVShmemState *s) {
>>                                        true,
>>                                        (i<<  16) | j,
>>                                        s->peers[i].eventfds[j]);
>> +            memory_region_add_eventfd(&s->ivshmem_pio,
>> +                                      DOORBELL,
>> +                                      4,
>> +                                      true,
>> +                                      (i<<  16) | j,
>> +                                      s->peers[i].eventfds[j]);
>>          }
>>      }
>>   }
>> @@ -495,6 +506,10 @@ static void ivshmem_read(void *opaque, const uint8_t * buf, int flags)
>>                          (incoming_posn<<  16) | guest_max_eventfd, 1)<  0) {
>>              fprintf(stderr, "ivshmem: ioeventfd not available\n");
>>          }
>> +        if (kvm_set_ioeventfd_pio_long(incoming_fd, s->pio_addr + DOORBELL,
>> +                        (incoming_posn<<  16) | guest_max_eventfd, 1)<  0) {
>> +            fprintf(stderr, "ivshmem: ioeventfd not available\n");
>> +        }
>>      }
>>
>>      return;
>> @@ -656,8 +671,10 @@ static int pci_ivshmem_init(PCIDevice *dev)
>>
>>      s->shm_fd = 0;
>>
>> -    memory_region_init_io(&s->ivshmem_mmio,&ivshmem_mmio_ops, s,
>> +    memory_region_init_io(&s->ivshmem_mmio,&ivshmem_io_ops, s,
>>                            "ivshmem-mmio", IVSHMEM_REG_BAR_SIZE);
>> +    memory_region_init_io(&s->ivshmem_pio,&ivshmem_io_ops, s,
>> +                          "ivshmem-pio", IVSHIO_REG_BAR_SIZE);
>>
>>      if (ivshmem_has_feature(s, IVSHMEM_IOEVENTFD)) {
>>          setup_ioeventfds(s);
>> @@ -666,6 +683,8 @@ static int pci_ivshmem_init(PCIDevice *dev)
>>      /* region for registers*/
>>      pci_register_bar(&s->dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY,
>>                       &s->ivshmem_mmio);
>> +    pci_register_bar(&s->dev, 3, PCI_BASE_ADDRESS_SPACE_IO,
>> +&s->ivshmem_pio);
>>
>>      memory_region_init(&s->bar, "ivshmem-bar2-container", s->ivshmem_size);
>>
>> @@ -742,6 +761,7 @@ static int pci_ivshmem_uninit(PCIDevice *dev)
>>      IVShmemState *s = DO_UPCAST(IVShmemState, dev, dev);
>>
>>      memory_region_destroy(&s->ivshmem_mmio);
>> +    memory_region_destroy(&s->ivshmem_pio);
>>      memory_region_del_subregion(&s->bar,&s->ivshmem);
>>      memory_region_destroy(&s->ivshmem);
>>      memory_region_destroy(&s->bar);
>> diff --git a/kvm-all.c b/kvm-all.c
>> index 5d500e1..737c2e2 100644
>> --- a/kvm-all.c
>> +++ b/kvm-all.c
>> @@ -1396,6 +1396,29 @@ int kvm_set_ioeventfd_mmio_long(int fd, uint32_t addr, uint32_t val, bool assign
>>      return 0;
>>   }
>>
>> +int kvm_set_ioeventfd_pio_long(int fd, uint32_t addr, uint32_t val, bool assign)
>> +{
>> +    struct kvm_ioeventfd kick = {
>> +        .datamatch = val,
>> +        .addr = addr,
>> +        .len = 4,
>> +        .flags = KVM_IOEVENTFD_FLAG_DATAMATCH | KVM_IOEVENTFD_FLAG_PIO,
>> +        .fd = fd,
>> +    };
>> +    int r;
>> +    if (!kvm_enabled()) {
>> +        return -ENOSYS;
>> +    }
>> +    if (!assign) {
>> +        kick.flags |= KVM_IOEVENTFD_FLAG_DEASSIGN;
>> +    }
>> +    r = kvm_vm_ioctl(kvm_state, KVM_IOEVENTFD,&kick);
>> +    if (r<  0) {
>> +        return r;
>> +    }
>> +    return 0;
>> +}
>> +
>>   int kvm_set_ioeventfd_pio_word(int fd, uint16_t addr, uint16_t val, bool assign)
>>   {
>>      struct kvm_ioeventfd kick = {
>> diff --git a/kvm.h b/kvm.h
>> index b15e1dd..c2373c9 100644
>> --- a/kvm.h
>> +++ b/kvm.h
>> @@ -198,6 +198,7 @@ int kvm_set_ioeventfd_mmio_long(int fd, uint32_t adr, uint32_t val, bool assign)
>>
>>   int kvm_set_irqfd(int gsi, int fd, bool assigned);
>>
>> +int kvm_set_ioeventfd_pio_long(int fd, uint32_t adr, uint32_t val, bool assign);
>>   int kvm_set_ioeventfd_pio_word(int fd, uint16_t adr, uint16_t val, bool assign);
>>
>>   typedef struct KVMMsiMessage {
>> --
>> 1.7.1
>>
> .
>

Patch

diff --git a/hw/ivshmem.c b/hw/ivshmem.c
index 242fbea..031cdd8 100644
--- a/hw/ivshmem.c
+++ b/hw/ivshmem.c
@@ -29,6 +29,7 @@ 
 #define IVSHMEM_MASTER  1
 
 #define IVSHMEM_REG_BAR_SIZE 0x100
+#define IVSHIO_REG_BAR_SIZE 0x10
 
 //#define DEBUG_IVSHMEM
 #ifdef DEBUG_IVSHMEM
@@ -57,8 +58,10 @@  typedef struct IVShmemState {
     CharDriverState **eventfd_chr;
     CharDriverState *server_chr;
     MemoryRegion ivshmem_mmio;
+    MemoryRegion ivshmem_pio;
 
     pcibus_t mmio_addr;
+    pcibus_t pio_addr;
     /* We might need to register the BAR before we actually have the memory.
      * So prepare a container MemoryRegion for the BAR immediately and
      * add a subregion when we have the memory.
@@ -234,7 +237,7 @@  static uint64_t ivshmem_io_read(void *opaque, target_phys_addr_t addr,
     return ret;
 }
 
-static const MemoryRegionOps ivshmem_mmio_ops = {
+static const MemoryRegionOps ivshmem_io_ops = {
     .read = ivshmem_io_read,
     .write = ivshmem_io_write,
     .endianness = DEVICE_NATIVE_ENDIAN,
@@ -348,6 +351,8 @@  static void close_guest_eventfds(IVShmemState *s, int posn)
     for (i = 0; i < guest_curr_max; i++) {
         kvm_set_ioeventfd_mmio_long(s->peers[posn].eventfds[i],
                     s->mmio_addr + DOORBELL, (posn << 16) | i, 0);
+        kvm_set_ioeventfd_pio_long(s->peers[posn].eventfds[i],
+                    s->pio_addr + DOORBELL, (posn << 16) | i, 0);
         close(s->peers[posn].eventfds[i]);
     }
 
@@ -367,6 +372,12 @@  static void setup_ioeventfds(IVShmemState *s) {
                                       true,
                                       (i << 16) | j,
                                       s->peers[i].eventfds[j]);
+            memory_region_add_eventfd(&s->ivshmem_pio,
+                                      DOORBELL,
+                                      4,
+                                      true,
+                                      (i << 16) | j,
+                                      s->peers[i].eventfds[j]);
         }
     }
 }
@@ -495,6 +506,10 @@  static void ivshmem_read(void *opaque, const uint8_t * buf, int flags)
                         (incoming_posn << 16) | guest_max_eventfd, 1) < 0) {
             fprintf(stderr, "ivshmem: ioeventfd not available\n");
         }
+        if (kvm_set_ioeventfd_pio_long(incoming_fd, s->pio_addr + DOORBELL,
+                        (incoming_posn << 16) | guest_max_eventfd, 1) < 0) {
+            fprintf(stderr, "ivshmem: ioeventfd not available\n");
+        }
     }
 
     return;
@@ -656,8 +671,10 @@  static int pci_ivshmem_init(PCIDevice *dev)
 
     s->shm_fd = 0;
 
-    memory_region_init_io(&s->ivshmem_mmio, &ivshmem_mmio_ops, s,
+    memory_region_init_io(&s->ivshmem_mmio, &ivshmem_io_ops, s,
                           "ivshmem-mmio", IVSHMEM_REG_BAR_SIZE);
+    memory_region_init_io(&s->ivshmem_pio, &ivshmem_io_ops, s,
+                          "ivshmem-pio", IVSHIO_REG_BAR_SIZE);
 
     if (ivshmem_has_feature(s, IVSHMEM_IOEVENTFD)) {
         setup_ioeventfds(s);
@@ -666,6 +683,8 @@  static int pci_ivshmem_init(PCIDevice *dev)
     /* region for registers*/
     pci_register_bar(&s->dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY,
                      &s->ivshmem_mmio);
+    pci_register_bar(&s->dev, 3, PCI_BASE_ADDRESS_SPACE_IO,
+                     &s->ivshmem_pio);
 
     memory_region_init(&s->bar, "ivshmem-bar2-container", s->ivshmem_size);
 
@@ -742,6 +761,7 @@  static int pci_ivshmem_uninit(PCIDevice *dev)
     IVShmemState *s = DO_UPCAST(IVShmemState, dev, dev);
 
     memory_region_destroy(&s->ivshmem_mmio);
+    memory_region_destroy(&s->ivshmem_pio);
     memory_region_del_subregion(&s->bar, &s->ivshmem);
     memory_region_destroy(&s->ivshmem);
     memory_region_destroy(&s->bar);
diff --git a/kvm-all.c b/kvm-all.c
index 5d500e1..737c2e2 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -1396,6 +1396,29 @@  int kvm_set_ioeventfd_mmio_long(int fd, uint32_t addr, uint32_t val, bool assign
     return 0;
 }
 
+int kvm_set_ioeventfd_pio_long(int fd, uint32_t addr, uint32_t val, bool assign)
+{
+    struct kvm_ioeventfd kick = {
+        .datamatch = val,
+        .addr = addr,
+        .len = 4,
+        .flags = KVM_IOEVENTFD_FLAG_DATAMATCH | KVM_IOEVENTFD_FLAG_PIO,
+        .fd = fd,
+    };
+    int r;
+    if (!kvm_enabled()) {
+        return -ENOSYS;
+    }
+    if (!assign) {
+        kick.flags |= KVM_IOEVENTFD_FLAG_DEASSIGN;
+    }
+    r = kvm_vm_ioctl(kvm_state, KVM_IOEVENTFD, &kick);
+    if (r < 0) {
+        return r;
+    }
+    return 0;
+}
+
 int kvm_set_ioeventfd_pio_word(int fd, uint16_t addr, uint16_t val, bool assign)
 {
     struct kvm_ioeventfd kick = {
diff --git a/kvm.h b/kvm.h
index b15e1dd..c2373c9 100644
--- a/kvm.h
+++ b/kvm.h
@@ -198,6 +198,7 @@  int kvm_set_ioeventfd_mmio_long(int fd, uint32_t adr, uint32_t val, bool assign)
 
 int kvm_set_irqfd(int gsi, int fd, bool assigned);
 
+int kvm_set_ioeventfd_pio_long(int fd, uint32_t adr, uint32_t val, bool assign);
 int kvm_set_ioeventfd_pio_word(int fd, uint16_t adr, uint16_t val, bool assign);
 
 typedef struct KVMMsiMessage {