Re: [PATCH] PCI: Add vf reset notification for pf
On Sun, 4 Feb 2024 14:12:57 +0800
Emily Deng wrote:
> When a vf has been reset, the pf wants to get notification to remove
> the vf out of schedule.
>
> Solution:
> Add the callback function in pci_driver sriov_vf_reset_notification.
> When vf reset happens, then call this callback function.
>
> Signed-off-by: Emily Deng
> ---
> drivers/pci/pci.c | 8
> include/linux/pci.h | 1 +
> 2 files changed, 9 insertions(+)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 60230da957e0..aca937b05531 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -4780,6 +4780,14 @@ EXPORT_SYMBOL_GPL(pcie_flr);
> */
> int pcie_reset_flr(struct pci_dev *dev, bool probe)
> {
> + struct pci_dev *pf_dev;
> +
> + if (dev->is_virtfn) {
> + pf_dev = dev->physfn;
> + if (pf_dev->driver->sriov_vf_reset_notification)
> +
> pf_dev->driver->sriov_vf_reset_notification(pf_dev, dev);
> + }
> +
> if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
> return -ENOTTY;
>
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index c69a2cc1f412..4fa31d9b0aa7 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -926,6 +926,7 @@ struct pci_driver {
> int (*sriov_configure)(struct pci_dev *dev, int num_vfs);
> /* On PF */ int (*sriov_set_msix_vec_count)(struct pci_dev *vf, int
> msix_vec_count); /* On PF */ u32 (*sriov_get_vf_total_msix)(struct
> pci_dev *pf);
> + void (*sriov_vf_reset_notification)(struct pci_dev *pf,
> struct pci_dev *vf); const struct pci_error_handlers *err_handler;
> const struct attribute_group **groups;
> const struct attribute_group **dev_groups;
Hi:
I would suggest you can provide a cover letter including a complete
picture that tells the background, detailed problem statement, the
solutions and plus the users. As this seems very like a generic change,
it needs a better justification to convince folks why this is the best
solution. Without a complete picture, the solution just looks like a
workaround.
Thanks,
Zhi.
Re: [PATCH] PCI: Add vf reset notification for pf
Am 04.02.24 um 07:12 schrieb Emily Deng:
When a vf has been reset, the pf wants to get notification to remove the vf
out of schedule.
Solution:
Add the callback function in pci_driver sriov_vf_reset_notification. When
vf reset happens, then call this callback function.
Well that doesn't make much sense. As other already noted as well a VF
should be an encapsulated representation of a physical devices
functionality.
AMD implemented that a bit different with a hypervisor to control which
PF functionality a VF exposes, but that doesn't mean that we can leak
this AMD specific handling into the common Linux PCI subsystem.
Additional to that a technical blocker is that when a VF is passed into
a VM you don't have access to the PF any more to make this reset
notification.
Regards,
Christian.
Signed-off-by: Emily Deng
---
drivers/pci/pci.c | 8
include/linux/pci.h | 1 +
2 files changed, 9 insertions(+)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 60230da957e0..aca937b05531 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4780,6 +4780,14 @@ EXPORT_SYMBOL_GPL(pcie_flr);
*/
int pcie_reset_flr(struct pci_dev *dev, bool probe)
{
+ struct pci_dev *pf_dev;
+
+ if (dev->is_virtfn) {
+ pf_dev = dev->physfn;
+ if (pf_dev->driver->sriov_vf_reset_notification)
+ pf_dev->driver->sriov_vf_reset_notification(pf_dev,
dev);
+ }
+
if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
return -ENOTTY;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index c69a2cc1f412..4fa31d9b0aa7 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -926,6 +926,7 @@ struct pci_driver {
int (*sriov_configure)(struct pci_dev *dev, int num_vfs); /* On PF */
int (*sriov_set_msix_vec_count)(struct pci_dev *vf, int
msix_vec_count); /* On PF */
u32 (*sriov_get_vf_total_msix)(struct pci_dev *pf);
+ void (*sriov_vf_reset_notification)(struct pci_dev *pf, struct pci_dev
*vf);
const struct pci_error_handlers *err_handler;
const struct attribute_group **groups;
const struct attribute_group **dev_groups;
Re: [PATCH] PCI: Add vf reset notification for pf
On Sun, Feb 04, 2024 at 02:12:57PM +0800, Emily Deng wrote:
> When a vf has been reset, the pf wants to get notification to remove the vf
> out of schedule.
It is very questionable if this is right thing to do. The idea of SR-IOV
is that VFs represent a physical device and they should be treated
separately from the PF.
In addition to that Keith said, this patch needs better justification.
Thanks
>
> Solution:
> Add the callback function in pci_driver sriov_vf_reset_notification. When
> vf reset happens, then call this callback function.
>
> Signed-off-by: Emily Deng
> ---
> drivers/pci/pci.c | 8
> include/linux/pci.h | 1 +
> 2 files changed, 9 insertions(+)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 60230da957e0..aca937b05531 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -4780,6 +4780,14 @@ EXPORT_SYMBOL_GPL(pcie_flr);
> */
> int pcie_reset_flr(struct pci_dev *dev, bool probe)
> {
> + struct pci_dev *pf_dev;
> +
> + if (dev->is_virtfn) {
> + pf_dev = dev->physfn;
> + if (pf_dev->driver->sriov_vf_reset_notification)
> + pf_dev->driver->sriov_vf_reset_notification(pf_dev,
> dev);
> + }
> +
> if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
> return -ENOTTY;
>
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index c69a2cc1f412..4fa31d9b0aa7 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -926,6 +926,7 @@ struct pci_driver {
> int (*sriov_configure)(struct pci_dev *dev, int num_vfs); /* On PF */
> int (*sriov_set_msix_vec_count)(struct pci_dev *vf, int
> msix_vec_count); /* On PF */
> u32 (*sriov_get_vf_total_msix)(struct pci_dev *pf);
> + void (*sriov_vf_reset_notification)(struct pci_dev *pf, struct pci_dev
> *vf);
> const struct pci_error_handlers *err_handler;
> const struct attribute_group **groups;
> const struct attribute_group **dev_groups;
> --
> 2.36.1
>
>
Re: [PATCH] PCI: Add vf reset notification for pf
On Sun, Feb 04, 2024 at 02:12:57PM +0800, Emily Deng wrote:
> @@ -926,6 +926,7 @@ struct pci_driver {
> int (*sriov_configure)(struct pci_dev *dev, int num_vfs); /* On PF */
> int (*sriov_set_msix_vec_count)(struct pci_dev *vf, int
> msix_vec_count); /* On PF */
> u32 (*sriov_get_vf_total_msix)(struct pci_dev *pf);
> + void (*sriov_vf_reset_notification)(struct pci_dev *pf, struct pci_dev
> *vf);
You've created a new callback, but there is no user. Could you resubmit
this with an in-kernel use case?
[PATCH] PCI: Add vf reset notification for pf
When a vf has been reset, the pf wants to get notification to remove the vf
out of schedule.
Solution:
Add the callback function in pci_driver sriov_vf_reset_notification. When
vf reset happens, then call this callback function.
Signed-off-by: Emily Deng
---
drivers/pci/pci.c | 8
include/linux/pci.h | 1 +
2 files changed, 9 insertions(+)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 60230da957e0..aca937b05531 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4780,6 +4780,14 @@ EXPORT_SYMBOL_GPL(pcie_flr);
*/
int pcie_reset_flr(struct pci_dev *dev, bool probe)
{
+ struct pci_dev *pf_dev;
+
+ if (dev->is_virtfn) {
+ pf_dev = dev->physfn;
+ if (pf_dev->driver->sriov_vf_reset_notification)
+ pf_dev->driver->sriov_vf_reset_notification(pf_dev,
dev);
+ }
+
if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
return -ENOTTY;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index c69a2cc1f412..4fa31d9b0aa7 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -926,6 +926,7 @@ struct pci_driver {
int (*sriov_configure)(struct pci_dev *dev, int num_vfs); /* On PF */
int (*sriov_set_msix_vec_count)(struct pci_dev *vf, int
msix_vec_count); /* On PF */
u32 (*sriov_get_vf_total_msix)(struct pci_dev *pf);
+ void (*sriov_vf_reset_notification)(struct pci_dev *pf, struct pci_dev
*vf);
const struct pci_error_handlers *err_handler;
const struct attribute_group **groups;
const struct attribute_group **dev_groups;
--
2.36.1
