Re: [virtio-dev] [RFC PATCH V2] virtio_pci: Add SR-IOV support

[Mark D Rustad]

> On Feb 25, 2018, at 7:20 AM, Yan Vugenfirer  wrote:
> 
> Small mistake in the commit message. Red Hat (Qumranet) vendor ID is 1af4, 
> virtio-net device ID is 1041.
> Should be:
> PF: vendor: 1af4 device: 1041 subvendor: 8086 subdevice: 15fe
> VF: vendor: 1af4 device: 1041 subvendor: 8086 subdevice: 05fe

You are so right. I will fix it before I send the updated patch that provides 
the generic helper that Christoph suggested. Thanks for catching my mislabeling.

--
Mark Rustad, mrus...@gmail.com



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Re: [virtio-dev] [RFC PATCH V2] virtio_pci: Add SR-IOV support

[Yan Vugenfirer]

> On 22 Feb 2018, at 19:52, Mark Rustad  wrote:
> 
> Hardware-realized virtio-pci devices can implement SR-IOV, so this
> patch enables its use. The device in question is an upcoming Intel
> NIC that implements both a virtio-net PF and virtio-net VFs. These
> are hardware realizations of what has been up to now been a software
> interface.
> 
> The device in question has the following 4-part PCI IDs:
> 
> PF: device: 1af4 vendor: 1041 subvendor: 8086 subdevice: 15fe
> VF: device: 1af4 vendor: 1041 subvendor: 8086 subdevice: 05fe

Small mistake in the commit message. Red Hat (Qumranet) vendor ID is 1af4, 
virtio-net device ID is 1041.
Should be:
PF: vendor: 1af4 device: 1041 subvendor: 8086 subdevice: 15fe
VF: vendor: 1af4 device: 1041 subvendor: 8086 subdevice: 05fe

Best regards,
Yan.

> 
> The patch needs no check for device ID, because the callback will
> never be made for devices that do not assert the capability or
> when run on a platform incapable of SR-IOV.
> 
> One reason for this patch is because the hardware requires the
> vendor ID of a VF to be the same as the vendor ID of the PF that
> created it. So it seemed logical to simply have a fully-functioning
> virtio-net PF create the VFs. This patch makes that possible.
> 
> Signed-off-by: Mark Rustad 
> Reviewed-by: Alexander Duyck 
> ---
> Changes in V2:
> - Simplified logic from previous version, removed added driver variable
> - Disable SR-IOV on driver removal excapt when VFs are assigned
> - Sent as RFC to virtio-dev, linux-pci, netdev, lkml and others
> ---
> drivers/virtio/virtio_pci_common.c |   47 
> 1 file changed, 47 insertions(+)
> 
> diff --git a/drivers/virtio/virtio_pci_common.c 
> b/drivers/virtio/virtio_pci_common.c
> index 48d4d1cf1cb6..78b53ffc4cee 100644
> --- a/drivers/virtio/virtio_pci_common.c
> +++ b/drivers/virtio/virtio_pci_common.c
> @@ -572,6 +572,47 @@ static int virtio_pci_probe(struct pci_dev *pci_dev,
>   return rc;
> }
> 
> +#ifdef CONFIG_PCI_IOV
> +static int virtio_pci_sriov_disable(struct pci_dev *pci_dev)
> +{
> + /* If vfs are assigned we cannot shut down SR-IOV without causing
> +  * issues, so just leave the hardware available.
> +  */
> + if (pci_vfs_assigned(pci_dev)) {
> + dev_warn(_dev->dev,
> +  "Unloading driver while VFs are assigned - VFs will 
> not be deallocated\n");
> + return -EPERM;
> + }
> + pci_disable_sriov(pci_dev);
> + return 0;
> +}
> +
> +static int virtio_pci_sriov_enable(struct pci_dev *pci_dev, int num_vfs)
> +{
> + int rc = 0;
> +
> + if (pci_num_vf(pci_dev))
> + return -EINVAL;
> +
> + rc = pci_enable_sriov(pci_dev, num_vfs);
> + if (rc) {
> + dev_warn(_dev->dev, "Failed to enable PCI sriov: %d\n", rc);
> + return rc;
> + }
> + dev_info(_dev->dev, "SR-IOV enabled with %d VFs\n", num_vfs);
> + return num_vfs;
> +}
> +
> +static int virtio_pci_sriov_configure(struct pci_dev *dev, int num_vfs)
> +{
> + if (num_vfs)
> + return virtio_pci_sriov_enable(dev, num_vfs);
> + if (!pci_num_vf(dev))
> + return -EINVAL;
> + return virtio_pci_sriov_disable(dev);
> +}
> +#endif /* CONFIG_PCI_IOV */
> +
> static void virtio_pci_remove(struct pci_dev *pci_dev)
> {
>   struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
> @@ -584,6 +625,9 @@ static void virtio_pci_remove(struct pci_dev *pci_dev)
>   else
>   virtio_pci_modern_remove(vp_dev);
> 
> +#ifdef CONFIG_PCI_IOV
> + virtio_pci_sriov_disable(pci_dev);
> +#endif
>   pci_disable_device(pci_dev);
>   put_device(dev);
> }
> @@ -596,6 +640,9 @@ static void virtio_pci_remove(struct pci_dev *pci_dev)
> #ifdef CONFIG_PM_SLEEP
>   .driver.pm  = _pci_pm_ops,
> #endif
> +#ifdef CONFIG_PCI_IOV
> + .sriov_configure = virtio_pci_sriov_configure,
> +#endif
> };
> 
> module_pci_driver(virtio_pci_driver);
> 
> 
> -
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> 

Re: [RFC PATCH V2] virtio_pci: Add SR-IOV support

[Rustad, Mark D]

> On Feb 22, 2018, at 10:26 AM, Christoph Hellwig  wrote:
> 
> Can we move this into common code as a a generic_sriov_configure
> helper?  Nothing is really virtio specific, and it seems like
> some other drivers could also use it, e.g. ena or nvme.

That seems like a good idea to me, especially if PCI developers concur.

-- 
Mark Rustad, Networking Division, Intel Corporation

Re: [RFC PATCH V2] virtio_pci: Add SR-IOV support

[Christoph Hellwig]

Can we move this into common code as a a generic_sriov_configure
helper?  Nothing is really virtio specific, and it seems like
some other drivers could also use it, e.g. ena or nvme.

[RFC PATCH V2] virtio_pci: Add SR-IOV support

[Mark Rustad]

Hardware-realized virtio-pci devices can implement SR-IOV, so this
patch enables its use. The device in question is an upcoming Intel
NIC that implements both a virtio-net PF and virtio-net VFs. These
are hardware realizations of what has been up to now been a software
interface.

The device in question has the following 4-part PCI IDs:

PF: device: 1af4 vendor: 1041 subvendor: 8086 subdevice: 15fe
VF: device: 1af4 vendor: 1041 subvendor: 8086 subdevice: 05fe

The patch needs no check for device ID, because the callback will
never be made for devices that do not assert the capability or
when run on a platform incapable of SR-IOV.

One reason for this patch is because the hardware requires the
vendor ID of a VF to be the same as the vendor ID of the PF that
created it. So it seemed logical to simply have a fully-functioning
virtio-net PF create the VFs. This patch makes that possible.

Signed-off-by: Mark Rustad 
Reviewed-by: Alexander Duyck 
---
Changes in V2:
- Simplified logic from previous version, removed added driver variable
- Disable SR-IOV on driver removal excapt when VFs are assigned
- Sent as RFC to virtio-dev, linux-pci, netdev, lkml and others
---
 drivers/virtio/virtio_pci_common.c |   47 
 1 file changed, 47 insertions(+)

diff --git a/drivers/virtio/virtio_pci_common.c 
b/drivers/virtio/virtio_pci_common.c
index 48d4d1cf1cb6..78b53ffc4cee 100644
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -572,6 +572,47 @@ static int virtio_pci_probe(struct pci_dev *pci_dev,
return rc;
 }
 
+#ifdef CONFIG_PCI_IOV
+static int virtio_pci_sriov_disable(struct pci_dev *pci_dev)
+{
+   /* If vfs are assigned we cannot shut down SR-IOV without causing
+* issues, so just leave the hardware available.
+*/
+   if (pci_vfs_assigned(pci_dev)) {
+   dev_warn(_dev->dev,
+"Unloading driver while VFs are assigned - VFs will 
not be deallocated\n");
+   return -EPERM;
+   }
+   pci_disable_sriov(pci_dev);
+   return 0;
+}
+
+static int virtio_pci_sriov_enable(struct pci_dev *pci_dev, int num_vfs)
+{
+   int rc = 0;
+
+   if (pci_num_vf(pci_dev))
+   return -EINVAL;
+
+   rc = pci_enable_sriov(pci_dev, num_vfs);
+   if (rc) {
+   dev_warn(_dev->dev, "Failed to enable PCI sriov: %d\n", rc);
+   return rc;
+   }
+   dev_info(_dev->dev, "SR-IOV enabled with %d VFs\n", num_vfs);
+   return num_vfs;
+}
+
+static int virtio_pci_sriov_configure(struct pci_dev *dev, int num_vfs)
+{
+   if (num_vfs)
+   return virtio_pci_sriov_enable(dev, num_vfs);
+   if (!pci_num_vf(dev))
+   return -EINVAL;
+   return virtio_pci_sriov_disable(dev);
+}
+#endif /* CONFIG_PCI_IOV */
+
 static void virtio_pci_remove(struct pci_dev *pci_dev)
 {
struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
@@ -584,6 +625,9 @@ static void virtio_pci_remove(struct pci_dev *pci_dev)
else
virtio_pci_modern_remove(vp_dev);
 
+#ifdef CONFIG_PCI_IOV
+   virtio_pci_sriov_disable(pci_dev);
+#endif
pci_disable_device(pci_dev);
put_device(dev);
 }
@@ -596,6 +640,9 @@ static void virtio_pci_remove(struct pci_dev *pci_dev)
 #ifdef CONFIG_PM_SLEEP
.driver.pm  = _pci_pm_ops,
 #endif
+#ifdef CONFIG_PCI_IOV
+   .sriov_configure = virtio_pci_sriov_configure,
+#endif
 };
 
 module_pci_driver(virtio_pci_driver);