[04/19] virtio: Implement get_shm_region for PCI transport
diff mbox series

Message ID 20190821175720.25901-5-vgoyal@redhat.com
State New
Headers show
Series
  • virtio-fs: Enable DAX support
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Commit Message

Vivek Goyal Aug. 21, 2019, 5:57 p.m. UTC
From: Sebastien Boeuf <sebastien.boeuf@intel.com>

On PCI the shm regions are found using capability entries;
find a region by searching for the capability.

Cc: kvm@vger.kernel.org
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: kbuild test robot <lkp@intel.com>
---
 drivers/virtio/virtio_pci_modern.c | 108 +++++++++++++++++++++++++++++
 include/uapi/linux/virtio_pci.h    |  11 ++-
 2 files changed, 118 insertions(+), 1 deletion(-)

Comments

piaojun Aug. 26, 2019, 1:43 a.m. UTC | #1
On 2019/8/22 1:57, Vivek Goyal wrote:
> From: Sebastien Boeuf <sebastien.boeuf@intel.com>
> 
> On PCI the shm regions are found using capability entries;
> find a region by searching for the capability.
> 
> Cc: kvm@vger.kernel.org
> Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> Signed-off-by: kbuild test robot <lkp@intel.com>
> ---
>  drivers/virtio/virtio_pci_modern.c | 108 +++++++++++++++++++++++++++++
>  include/uapi/linux/virtio_pci.h    |  11 ++-
>  2 files changed, 118 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> index 7abcc50838b8..1cdedd93f42a 100644
> --- a/drivers/virtio/virtio_pci_modern.c
> +++ b/drivers/virtio/virtio_pci_modern.c
> @@ -443,6 +443,112 @@ static void del_vq(struct virtio_pci_vq_info *info)
>  	vring_del_virtqueue(vq);
>  }
>  
> +static int virtio_pci_find_shm_cap(struct pci_dev *dev,
> +                                   u8 required_id,
> +                                   u8 *bar, u64 *offset, u64 *len)
> +{
> +	int pos;
> +
> +        for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
> +             pos > 0;
> +             pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
> +		u8 type, cap_len, id;
> +                u32 tmp32;
> +                u64 res_offset, res_length;
> +
> +		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> +                                                         cfg_type),
> +                                     &type);
> +                if (type != VIRTIO_PCI_CAP_SHARED_MEMORY_CFG)
> +                        continue;
> +
> +		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> +                                                         cap_len),
> +                                     &cap_len);
> +		if (cap_len != sizeof(struct virtio_pci_cap64)) {
> +		        printk(KERN_ERR "%s: shm cap with bad size offset: %d size: %d\n",
> +                               __func__, pos, cap_len);
> +                        continue;
> +                }
> +
> +		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> +                                                         id),
> +                                     &id);
> +                if (id != required_id)
> +                        continue;
> +
> +                /* Type, and ID match, looks good */
> +                pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> +                                                         bar),
> +                                     bar);
> +
> +                /* Read the lower 32bit of length and offset */
> +                pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap, offset),
> +                                      &tmp32);
> +                res_offset = tmp32;
> +                pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap, length),
> +                                      &tmp32);
> +                res_length = tmp32;
> +
> +                /* and now the top half */
> +                pci_read_config_dword(dev,
> +                                      pos + offsetof(struct virtio_pci_cap64,
> +                                                     offset_hi),
> +                                      &tmp32);
> +                res_offset |= ((u64)tmp32) << 32;
> +                pci_read_config_dword(dev,
> +                                      pos + offsetof(struct virtio_pci_cap64,
> +                                                     length_hi),
> +                                      &tmp32);
> +                res_length |= ((u64)tmp32) << 32;
> +
> +                *offset = res_offset;
> +                *len = res_length;
> +
> +                return pos;
> +        }
> +        return 0;
> +}
> +
> +static bool vp_get_shm_region(struct virtio_device *vdev,
> +			      struct virtio_shm_region *region, u8 id)
> +{
> +	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> +	struct pci_dev *pci_dev = vp_dev->pci_dev;
> +	u8 bar;
> +	u64 offset, len;
> +	phys_addr_t phys_addr;
> +	size_t bar_len;
> +	char *bar_name;

'char *bar_name' should be cleaned up to avoid compiling warning. And I
wonder if you mix tab and blankspace for code indent? Or it's just my
email display problem?

Thanks,
Jun
Vivek Goyal Aug. 26, 2019, 1:06 p.m. UTC | #2
On Mon, Aug 26, 2019 at 09:43:08AM +0800, piaojun wrote:

[..]
> > +static bool vp_get_shm_region(struct virtio_device *vdev,
> > +			      struct virtio_shm_region *region, u8 id)
> > +{
> > +	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> > +	struct pci_dev *pci_dev = vp_dev->pci_dev;
> > +	u8 bar;
> > +	u64 offset, len;
> > +	phys_addr_t phys_addr;
> > +	size_t bar_len;
> > +	char *bar_name;
> 
> 'char *bar_name' should be cleaned up to avoid compiling warning. And I
> wonder if you mix tab and blankspace for code indent? Or it's just my
> email display problem?

Will get rid of now unused bar_name. 

Generally git flags if there are tab/space issues. I did not see any. So
if you see something, point it out and I will fix it.

Vivek
Cornelia Huck Aug. 27, 2019, 8:34 a.m. UTC | #3
On Wed, 21 Aug 2019 13:57:05 -0400
Vivek Goyal <vgoyal@redhat.com> wrote:

> From: Sebastien Boeuf <sebastien.boeuf@intel.com>
> 
> On PCI the shm regions are found using capability entries;
> find a region by searching for the capability.
> 
> Cc: kvm@vger.kernel.org
> Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> Signed-off-by: kbuild test robot <lkp@intel.com>

An s-o-b by a test robot looks a bit odd.

> ---
>  drivers/virtio/virtio_pci_modern.c | 108 +++++++++++++++++++++++++++++
>  include/uapi/linux/virtio_pci.h    |  11 ++-
>  2 files changed, 118 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> index 7abcc50838b8..1cdedd93f42a 100644
> --- a/drivers/virtio/virtio_pci_modern.c
> +++ b/drivers/virtio/virtio_pci_modern.c
> @@ -443,6 +443,112 @@ static void del_vq(struct virtio_pci_vq_info *info)
>  	vring_del_virtqueue(vq);
>  }
>  
> +static int virtio_pci_find_shm_cap(struct pci_dev *dev,
> +                                   u8 required_id,
> +                                   u8 *bar, u64 *offset, u64 *len)
> +{
> +	int pos;
> +
> +        for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);

Indentation looks a bit off here.

> +             pos > 0;
> +             pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
> +		u8 type, cap_len, id;
> +                u32 tmp32;

Here as well.

> +                u64 res_offset, res_length;
> +
> +		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> +                                                         cfg_type),
> +                                     &type);
> +                if (type != VIRTIO_PCI_CAP_SHARED_MEMORY_CFG)

And here.

> +                        continue;
> +
> +		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> +                                                         cap_len),
> +                                     &cap_len);
> +		if (cap_len != sizeof(struct virtio_pci_cap64)) {
> +		        printk(KERN_ERR "%s: shm cap with bad size offset: %d size: %d\n",
> +                               __func__, pos, cap_len);

Probably better to use dev_warn() instead of printk.

> +                        continue;
> +                }

Indentation looks off again (might be a space vs tabs issue; maybe
check the whole patch for indentation problems?)

> +
> +		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> +                                                         id),
> +                                     &id);
> +                if (id != required_id)
> +                        continue;
> +
> +                /* Type, and ID match, looks good */
> +                pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> +                                                         bar),
> +                                     bar);
> +
> +                /* Read the lower 32bit of length and offset */
> +                pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap, offset),
> +                                      &tmp32);
> +                res_offset = tmp32;
> +                pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap, length),
> +                                      &tmp32);
> +                res_length = tmp32;
> +
> +                /* and now the top half */
> +                pci_read_config_dword(dev,
> +                                      pos + offsetof(struct virtio_pci_cap64,
> +                                                     offset_hi),
> +                                      &tmp32);
> +                res_offset |= ((u64)tmp32) << 32;
> +                pci_read_config_dword(dev,
> +                                      pos + offsetof(struct virtio_pci_cap64,
> +                                                     length_hi),
> +                                      &tmp32);
> +                res_length |= ((u64)tmp32) << 32;
> +
> +                *offset = res_offset;
> +                *len = res_length;
> +
> +                return pos;
> +        }
> +        return 0;
> +}
> +
> +static bool vp_get_shm_region(struct virtio_device *vdev,
> +			      struct virtio_shm_region *region, u8 id)
> +{
> +	struct virtio_pci_device *vp_dev = to_vp_device(vdev);

This whole function looks like it is indented incorrectly.

> +	struct pci_dev *pci_dev = vp_dev->pci_dev;
> +	u8 bar;
> +	u64 offset, len;
> +	phys_addr_t phys_addr;
> +	size_t bar_len;
> +	char *bar_name;
> +	int ret;
> +
> +	if (!virtio_pci_find_shm_cap(pci_dev, id, &bar, &offset, &len)) {
> +		return false;
> +	}

You can drop the curly braces.

> +
> +	ret = pci_request_region(pci_dev, bar, "virtio-pci-shm");
> +	if (ret < 0) {
> +		dev_err(&pci_dev->dev, "%s: failed to request BAR\n",
> +			__func__);
> +		return false;
> +	}
> +
> +	phys_addr = pci_resource_start(pci_dev, bar);
> +	bar_len = pci_resource_len(pci_dev, bar);
> +
> +        if (offset + len > bar_len) {
> +                dev_err(&pci_dev->dev,
> +                        "%s: bar shorter than cap offset+len\n",
> +                        __func__);
> +                return false;
> +        }
> +
> +	region->len = len;
> +	region->addr = (u64) phys_addr + offset;
> +
> +	return true;
> +}
> +
>  static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
>  	.get		= NULL,
>  	.set		= NULL,

Apart from the coding style nits, the logic of the patch looks sane to
me.

(...)

As does the rest of the patch.
Cornelia Huck Aug. 27, 2019, 8:46 a.m. UTC | #4
On Tue, 27 Aug 2019 10:34:57 +0200
Cornelia Huck <cohuck@redhat.com> wrote:

> On Wed, 21 Aug 2019 13:57:05 -0400
> Vivek Goyal <vgoyal@redhat.com> wrote:

> > +static bool vp_get_shm_region(struct virtio_device *vdev,
> > +			      struct virtio_shm_region *region, u8 id)
> > +{
> > +	struct virtio_pci_device *vp_dev = to_vp_device(vdev);  
> 
> This whole function looks like it is indented incorrectly.

Hmpf, it looks like my mail client is squashing tabs, so the
indentation looks off here, but is probably fine :) It's the function
above that seems to have a mix of spaces and tabs.

> 
> > +	struct pci_dev *pci_dev = vp_dev->pci_dev;
> > +	u8 bar;
> > +	u64 offset, len;
> > +	phys_addr_t phys_addr;
> > +	size_t bar_len;
> > +	char *bar_name;
> > +	int ret;
piaojun Aug. 27, 2019, 9:41 a.m. UTC | #5
On 2019/8/26 21:06, Vivek Goyal wrote:
> On Mon, Aug 26, 2019 at 09:43:08AM +0800, piaojun wrote:
> 
> [..]
>>> +static bool vp_get_shm_region(struct virtio_device *vdev,
>>> +			      struct virtio_shm_region *region, u8 id)
>>> +{
>>> +	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
>>> +	struct pci_dev *pci_dev = vp_dev->pci_dev;
>>> +	u8 bar;
>>> +	u64 offset, len;
>>> +	phys_addr_t phys_addr;
>>> +	size_t bar_len;
>>> +	char *bar_name;
>>
>> 'char *bar_name' should be cleaned up to avoid compiling warning. And I
>> wonder if you mix tab and blankspace for code indent? Or it's just my
>> email display problem?
> 
> Will get rid of now unused bar_name. 
> 
OK

> Generally git flags if there are tab/space issues. I did not see any. So
> if you see something, point it out and I will fix it.
> 

cohuck found the same indent problem and pointed them in another email.

Jun
Vivek Goyal Aug. 27, 2019, 11:53 a.m. UTC | #6
On Tue, Aug 27, 2019 at 10:34:57AM +0200, Cornelia Huck wrote:
> On Wed, 21 Aug 2019 13:57:05 -0400
> Vivek Goyal <vgoyal@redhat.com> wrote:
> 
> > From: Sebastien Boeuf <sebastien.boeuf@intel.com>
> > 
> > On PCI the shm regions are found using capability entries;
> > find a region by searching for the capability.
> > 
> > Cc: kvm@vger.kernel.org
> > Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
> > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> > Signed-off-by: kbuild test robot <lkp@intel.com>
> 
> An s-o-b by a test robot looks a bit odd.

I think one of the fixes came from the robot and that's why I put s-o-b
from the robot as well. 

I will review the whole patch and fix all the intendation issues.

Vivek

> 
> > ---
> >  drivers/virtio/virtio_pci_modern.c | 108 +++++++++++++++++++++++++++++
> >  include/uapi/linux/virtio_pci.h    |  11 ++-
> >  2 files changed, 118 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> > index 7abcc50838b8..1cdedd93f42a 100644
> > --- a/drivers/virtio/virtio_pci_modern.c
> > +++ b/drivers/virtio/virtio_pci_modern.c
> > @@ -443,6 +443,112 @@ static void del_vq(struct virtio_pci_vq_info *info)
> >  	vring_del_virtqueue(vq);
> >  }
> >  
> > +static int virtio_pci_find_shm_cap(struct pci_dev *dev,
> > +                                   u8 required_id,
> > +                                   u8 *bar, u64 *offset, u64 *len)
> > +{
> > +	int pos;
> > +
> > +        for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
> 
> Indentation looks a bit off here.
> 
> > +             pos > 0;
> > +             pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
> > +		u8 type, cap_len, id;
> > +                u32 tmp32;
> 
> Here as well.
> 
> > +                u64 res_offset, res_length;
> > +
> > +		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> > +                                                         cfg_type),
> > +                                     &type);
> > +                if (type != VIRTIO_PCI_CAP_SHARED_MEMORY_CFG)
> 
> And here.
> 
> > +                        continue;
> > +
> > +		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> > +                                                         cap_len),
> > +                                     &cap_len);
> > +		if (cap_len != sizeof(struct virtio_pci_cap64)) {
> > +		        printk(KERN_ERR "%s: shm cap with bad size offset: %d size: %d\n",
> > +                               __func__, pos, cap_len);
> 
> Probably better to use dev_warn() instead of printk.
> 
> > +                        continue;
> > +                }
> 
> Indentation looks off again (might be a space vs tabs issue; maybe
> check the whole patch for indentation problems?)
> 
> > +
> > +		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> > +                                                         id),
> > +                                     &id);
> > +                if (id != required_id)
> > +                        continue;
> > +
> > +                /* Type, and ID match, looks good */
> > +                pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> > +                                                         bar),
> > +                                     bar);
> > +
> > +                /* Read the lower 32bit of length and offset */
> > +                pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap, offset),
> > +                                      &tmp32);
> > +                res_offset = tmp32;
> > +                pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap, length),
> > +                                      &tmp32);
> > +                res_length = tmp32;
> > +
> > +                /* and now the top half */
> > +                pci_read_config_dword(dev,
> > +                                      pos + offsetof(struct virtio_pci_cap64,
> > +                                                     offset_hi),
> > +                                      &tmp32);
> > +                res_offset |= ((u64)tmp32) << 32;
> > +                pci_read_config_dword(dev,
> > +                                      pos + offsetof(struct virtio_pci_cap64,
> > +                                                     length_hi),
> > +                                      &tmp32);
> > +                res_length |= ((u64)tmp32) << 32;
> > +
> > +                *offset = res_offset;
> > +                *len = res_length;
> > +
> > +                return pos;
> > +        }
> > +        return 0;
> > +}
> > +
> > +static bool vp_get_shm_region(struct virtio_device *vdev,
> > +			      struct virtio_shm_region *region, u8 id)
> > +{
> > +	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> 
> This whole function looks like it is indented incorrectly.
> 
> > +	struct pci_dev *pci_dev = vp_dev->pci_dev;
> > +	u8 bar;
> > +	u64 offset, len;
> > +	phys_addr_t phys_addr;
> > +	size_t bar_len;
> > +	char *bar_name;
> > +	int ret;
> > +
> > +	if (!virtio_pci_find_shm_cap(pci_dev, id, &bar, &offset, &len)) {
> > +		return false;
> > +	}
> 
> You can drop the curly braces.
> 
> > +
> > +	ret = pci_request_region(pci_dev, bar, "virtio-pci-shm");
> > +	if (ret < 0) {
> > +		dev_err(&pci_dev->dev, "%s: failed to request BAR\n",
> > +			__func__);
> > +		return false;
> > +	}
> > +
> > +	phys_addr = pci_resource_start(pci_dev, bar);
> > +	bar_len = pci_resource_len(pci_dev, bar);
> > +
> > +        if (offset + len > bar_len) {
> > +                dev_err(&pci_dev->dev,
> > +                        "%s: bar shorter than cap offset+len\n",
> > +                        __func__);
> > +                return false;
> > +        }
> > +
> > +	region->len = len;
> > +	region->addr = (u64) phys_addr + offset;
> > +
> > +	return true;
> > +}
> > +
> >  static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
> >  	.get		= NULL,
> >  	.set		= NULL,
> 
> Apart from the coding style nits, the logic of the patch looks sane to
> me.
> 
> (...)
> 
> As does the rest of the patch.

Patch
diff mbox series

diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index 7abcc50838b8..1cdedd93f42a 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -443,6 +443,112 @@  static void del_vq(struct virtio_pci_vq_info *info)
 	vring_del_virtqueue(vq);
 }
 
+static int virtio_pci_find_shm_cap(struct pci_dev *dev,
+                                   u8 required_id,
+                                   u8 *bar, u64 *offset, u64 *len)
+{
+	int pos;
+
+        for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
+             pos > 0;
+             pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
+		u8 type, cap_len, id;
+                u32 tmp32;
+                u64 res_offset, res_length;
+
+		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
+                                                         cfg_type),
+                                     &type);
+                if (type != VIRTIO_PCI_CAP_SHARED_MEMORY_CFG)
+                        continue;
+
+		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
+                                                         cap_len),
+                                     &cap_len);
+		if (cap_len != sizeof(struct virtio_pci_cap64)) {
+		        printk(KERN_ERR "%s: shm cap with bad size offset: %d size: %d\n",
+                               __func__, pos, cap_len);
+                        continue;
+                }
+
+		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
+                                                         id),
+                                     &id);
+                if (id != required_id)
+                        continue;
+
+                /* Type, and ID match, looks good */
+                pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
+                                                         bar),
+                                     bar);
+
+                /* Read the lower 32bit of length and offset */
+                pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap, offset),
+                                      &tmp32);
+                res_offset = tmp32;
+                pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap, length),
+                                      &tmp32);
+                res_length = tmp32;
+
+                /* and now the top half */
+                pci_read_config_dword(dev,
+                                      pos + offsetof(struct virtio_pci_cap64,
+                                                     offset_hi),
+                                      &tmp32);
+                res_offset |= ((u64)tmp32) << 32;
+                pci_read_config_dword(dev,
+                                      pos + offsetof(struct virtio_pci_cap64,
+                                                     length_hi),
+                                      &tmp32);
+                res_length |= ((u64)tmp32) << 32;
+
+                *offset = res_offset;
+                *len = res_length;
+
+                return pos;
+        }
+        return 0;
+}
+
+static bool vp_get_shm_region(struct virtio_device *vdev,
+			      struct virtio_shm_region *region, u8 id)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+	struct pci_dev *pci_dev = vp_dev->pci_dev;
+	u8 bar;
+	u64 offset, len;
+	phys_addr_t phys_addr;
+	size_t bar_len;
+	char *bar_name;
+	int ret;
+
+	if (!virtio_pci_find_shm_cap(pci_dev, id, &bar, &offset, &len)) {
+		return false;
+	}
+
+	ret = pci_request_region(pci_dev, bar, "virtio-pci-shm");
+	if (ret < 0) {
+		dev_err(&pci_dev->dev, "%s: failed to request BAR\n",
+			__func__);
+		return false;
+	}
+
+	phys_addr = pci_resource_start(pci_dev, bar);
+	bar_len = pci_resource_len(pci_dev, bar);
+
+        if (offset + len > bar_len) {
+                dev_err(&pci_dev->dev,
+                        "%s: bar shorter than cap offset+len\n",
+                        __func__);
+                return false;
+        }
+
+	region->len = len;
+	region->addr = (u64) phys_addr + offset;
+
+	return true;
+}
+
 static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
 	.get		= NULL,
 	.set		= NULL,
@@ -457,6 +563,7 @@  static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
 	.bus_name	= vp_bus_name,
 	.set_vq_affinity = vp_set_vq_affinity,
 	.get_vq_affinity = vp_get_vq_affinity,
+	.get_shm_region  = vp_get_shm_region,
 };
 
 static const struct virtio_config_ops virtio_pci_config_ops = {
@@ -473,6 +580,7 @@  static const struct virtio_config_ops virtio_pci_config_ops = {
 	.bus_name	= vp_bus_name,
 	.set_vq_affinity = vp_set_vq_affinity,
 	.get_vq_affinity = vp_get_vq_affinity,
+	.get_shm_region  = vp_get_shm_region,
 };
 
 /**
diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
index 90007a1abcab..fe9f43680a1d 100644
--- a/include/uapi/linux/virtio_pci.h
+++ b/include/uapi/linux/virtio_pci.h
@@ -113,6 +113,8 @@ 
 #define VIRTIO_PCI_CAP_DEVICE_CFG	4
 /* PCI configuration access */
 #define VIRTIO_PCI_CAP_PCI_CFG		5
+/* Additional shared memory capability */
+#define VIRTIO_PCI_CAP_SHARED_MEMORY_CFG 8
 
 /* This is the PCI capability header: */
 struct virtio_pci_cap {
@@ -121,11 +123,18 @@  struct virtio_pci_cap {
 	__u8 cap_len;		/* Generic PCI field: capability length */
 	__u8 cfg_type;		/* Identifies the structure. */
 	__u8 bar;		/* Where to find it. */
-	__u8 padding[3];	/* Pad to full dword. */
+	__u8 id;		/* Multiple capabilities of the same type */
+	__u8 padding[2];	/* Pad to full dword. */
 	__le32 offset;		/* Offset within bar. */
 	__le32 length;		/* Length of the structure, in bytes. */
 };
 
+struct virtio_pci_cap64 {
+       struct virtio_pci_cap cap;
+       __le32 offset_hi;             /* Most sig 32 bits of offset */
+       __le32 length_hi;             /* Most sig 32 bits of length */
+};
+
 struct virtio_pci_notify_cap {
 	struct virtio_pci_cap cap;
 	__le32 notify_off_multiplier;	/* Multiplier for queue_notify_off. */