1. Patchew
  2. linux
  3. [PATCH v2 0/3] Allow dyn MSI-X vector allocation of MANA
  4. View patch

[PATCH v2 1/3] PCI: Export pci_msix_prepare_desc() for dynamic MSI-X alloc

Shradha Gupta posted 3 patches 9 months, 2 weeks ago
There is a newer version of this series
[PATCH v2 1/3] PCI: Export pci_msix_prepare_desc() for dynamic MSI-X alloc
Posted by Shradha Gupta 9 months, 2 weeks ago 
For supporting dynamic MSI-X vector allocation by PCI controllers, enabling
the flag MSI_FLAG_PCI_MSIX_ALLOC_DYN is not enough, msix_prepare_msi_desc()
to prepare the desc is also needed.

Export pci_msix_prepare_desc() to allow PCI controllers to support dynamic
MSI-X vector allocation.

Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
---
 drivers/pci/msi/irqdomain.c | 5 +++--
 include/linux/msi.h         | 2 ++
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/msi/irqdomain.c b/drivers/pci/msi/irqdomain.c
index d7ba8795d60f..43129aa6d6c7 100644
--- a/drivers/pci/msi/irqdomain.c
+++ b/drivers/pci/msi/irqdomain.c
@@ -222,13 +222,14 @@ static void pci_irq_unmask_msix(struct irq_data *data)
 	pci_msix_unmask(irq_data_get_msi_desc(data));
 }
 
-static void pci_msix_prepare_desc(struct irq_domain *domain, msi_alloc_info_t *arg,
-				  struct msi_desc *desc)
+void pci_msix_prepare_desc(struct irq_domain *domain, msi_alloc_info_t *arg,
+			   struct msi_desc *desc)
 {
 	/* Don't fiddle with preallocated MSI descriptors */
 	if (!desc->pci.mask_base)
 		msix_prepare_msi_desc(to_pci_dev(desc->dev), desc);
 }
+EXPORT_SYMBOL_GPL(pci_msix_prepare_desc);
 
 static const struct msi_domain_template pci_msix_template = {
 	.chip = {
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 86e42742fd0f..d5864d5e75c2 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -691,6 +691,8 @@ struct irq_domain *pci_msi_create_irq_domain(struct fwnode_handle *fwnode,
 					     struct irq_domain *parent);
 u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev);
 struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev);
+void pci_msix_prepare_desc(struct irq_domain *domain, msi_alloc_info_t *arg,
+			   struct msi_desc *desc);
 #else /* CONFIG_PCI_MSI */
 static inline struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev)
 {
-- 
2.34.1
Re: [PATCH v2 1/3] PCI: Export pci_msix_prepare_desc() for dynamic MSI-X alloc
Posted by Bjorn Helgaas 9 months, 2 weeks ago 
On Fri, Apr 25, 2025 at 03:53:57AM -0700, Shradha Gupta wrote:
> For supporting dynamic MSI-X vector allocation by PCI controllers, enabling
> the flag MSI_FLAG_PCI_MSIX_ALLOC_DYN is not enough, msix_prepare_msi_desc()
> to prepare the desc is also needed.
> 
> Export pci_msix_prepare_desc() to allow PCI controllers to support dynamic
> MSI-X vector allocation.
> 
> Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>

Thanks for the update and for splitting this from the hv driver
update.  Will watch for Thomas's ack here.

For future postings, you might consider limiting the "To:" line to
people you expect to actually act on the patch, and moving the rest to
"Cc:".

> ---
>  drivers/pci/msi/irqdomain.c | 5 +++--
>  include/linux/msi.h         | 2 ++
>  2 files changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/msi/irqdomain.c b/drivers/pci/msi/irqdomain.c
> index d7ba8795d60f..43129aa6d6c7 100644
> --- a/drivers/pci/msi/irqdomain.c
> +++ b/drivers/pci/msi/irqdomain.c
> @@ -222,13 +222,14 @@ static void pci_irq_unmask_msix(struct irq_data *data)
>  	pci_msix_unmask(irq_data_get_msi_desc(data));
>  }
>  
> -static void pci_msix_prepare_desc(struct irq_domain *domain, msi_alloc_info_t *arg,
> -				  struct msi_desc *desc)
> +void pci_msix_prepare_desc(struct irq_domain *domain, msi_alloc_info_t *arg,
> +			   struct msi_desc *desc)
>  {
>  	/* Don't fiddle with preallocated MSI descriptors */
>  	if (!desc->pci.mask_base)
>  		msix_prepare_msi_desc(to_pci_dev(desc->dev), desc);
>  }
> +EXPORT_SYMBOL_GPL(pci_msix_prepare_desc);
>  
>  static const struct msi_domain_template pci_msix_template = {
>  	.chip = {
> diff --git a/include/linux/msi.h b/include/linux/msi.h
> index 86e42742fd0f..d5864d5e75c2 100644
> --- a/include/linux/msi.h
> +++ b/include/linux/msi.h
> @@ -691,6 +691,8 @@ struct irq_domain *pci_msi_create_irq_domain(struct fwnode_handle *fwnode,
>  					     struct irq_domain *parent);
>  u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev);
>  struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev);
> +void pci_msix_prepare_desc(struct irq_domain *domain, msi_alloc_info_t *arg,
> +			   struct msi_desc *desc);
>  #else /* CONFIG_PCI_MSI */
>  static inline struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev)
>  {
> -- 
> 2.34.1
>
Re: [PATCH v2 1/3] PCI: Export pci_msix_prepare_desc() for dynamic MSI-X alloc
Posted by Thomas Gleixner 9 months, 2 weeks ago 
On Fri, Apr 25 2025 at 11:37, Bjorn Helgaas wrote:

Subject prefix wants to be PCI/MSI

  git log --format=oneline path/to/file

gives you a pretty decent hint



> On Fri, Apr 25, 2025 at 03:53:57AM -0700, Shradha Gupta wrote:
>> For supporting dynamic MSI-X vector allocation by PCI controllers, enabling
>> the flag MSI_FLAG_PCI_MSIX_ALLOC_DYN is not enough, msix_prepare_msi_desc()
>> to prepare the desc is also needed.

Please write things out: ... to prepare the MSI descriptor ....

This is not twitter.

>> Export pci_msix_prepare_desc() to allow PCI controllers to support dynamic
>> MSI-X vector allocation.
>> 
>> Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
>> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>

> Thanks for the update and for splitting this from the hv driver
> update.  Will watch for Thomas's ack here.

Other than that:

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Re: [PATCH v2 1/3] PCI: Export pci_msix_prepare_desc() for dynamic MSI-X alloc
Posted by Shradha Gupta 9 months, 2 weeks ago 
On Mon, Apr 28, 2025 at 02:22:57PM +0200, Thomas Gleixner wrote:
> On Fri, Apr 25 2025 at 11:37, Bjorn Helgaas wrote:
> 
> Subject prefix wants to be PCI/MSI
> 
>   git log --format=oneline path/to/file
> 
> gives you a pretty decent hint
> 
> 
> 
> > On Fri, Apr 25, 2025 at 03:53:57AM -0700, Shradha Gupta wrote:
> >> For supporting dynamic MSI-X vector allocation by PCI controllers, enabling
> >> the flag MSI_FLAG_PCI_MSIX_ALLOC_DYN is not enough, msix_prepare_msi_desc()
> >> to prepare the desc is also needed.
> 
> Please write things out: ... to prepare the MSI descriptor ....
> 
> This is not twitter.
> 
> >> Export pci_msix_prepare_desc() to allow PCI controllers to support dynamic
> >> MSI-X vector allocation.
> >> 
> >> Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
> >> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
> 
> > Thanks for the update and for splitting this from the hv driver
> > update.  Will watch for Thomas's ack here.
> 
> Other than that:
> 
> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

Thank you for all the comments Thomas.
I'll be mindful of these going forward.

regards,
Shradha.
Re: [PATCH v2 1/3] PCI: Export pci_msix_prepare_desc() for dynamic MSI-X alloc
Posted by Shradha Gupta 9 months, 2 weeks ago 
On Fri, Apr 25, 2025 at 11:37:48AM -0500, Bjorn Helgaas wrote:
> On Fri, Apr 25, 2025 at 03:53:57AM -0700, Shradha Gupta wrote:
> > For supporting dynamic MSI-X vector allocation by PCI controllers, enabling
> > the flag MSI_FLAG_PCI_MSIX_ALLOC_DYN is not enough, msix_prepare_msi_desc()
> > to prepare the desc is also needed.
> > 
> > Export pci_msix_prepare_desc() to allow PCI controllers to support dynamic
> > MSI-X vector allocation.
> > 
> > Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
> > Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
> 
> Thanks for the update and for splitting this from the hv driver
> update.  Will watch for Thomas's ack here.
> 
> For future postings, you might consider limiting the "To:" line to
> people you expect to actually act on the patch, and moving the rest to
> "Cc:".

Thanks Bjorn, Noted.
> 
> > ---
> >  drivers/pci/msi/irqdomain.c | 5 +++--
> >  include/linux/msi.h         | 2 ++
> >  2 files changed, 5 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/pci/msi/irqdomain.c b/drivers/pci/msi/irqdomain.c
> > index d7ba8795d60f..43129aa6d6c7 100644
> > --- a/drivers/pci/msi/irqdomain.c
> > +++ b/drivers/pci/msi/irqdomain.c
> > @@ -222,13 +222,14 @@ static void pci_irq_unmask_msix(struct irq_data *data)
> >  	pci_msix_unmask(irq_data_get_msi_desc(data));
> >  }
> >  
> > -static void pci_msix_prepare_desc(struct irq_domain *domain, msi_alloc_info_t *arg,
> > -				  struct msi_desc *desc)
> > +void pci_msix_prepare_desc(struct irq_domain *domain, msi_alloc_info_t *arg,
> > +			   struct msi_desc *desc)
> >  {
> >  	/* Don't fiddle with preallocated MSI descriptors */
> >  	if (!desc->pci.mask_base)
> >  		msix_prepare_msi_desc(to_pci_dev(desc->dev), desc);
> >  }
> > +EXPORT_SYMBOL_GPL(pci_msix_prepare_desc);
> >  
> >  static const struct msi_domain_template pci_msix_template = {
> >  	.chip = {
> > diff --git a/include/linux/msi.h b/include/linux/msi.h
> > index 86e42742fd0f..d5864d5e75c2 100644
> > --- a/include/linux/msi.h
> > +++ b/include/linux/msi.h
> > @@ -691,6 +691,8 @@ struct irq_domain *pci_msi_create_irq_domain(struct fwnode_handle *fwnode,
> >  					     struct irq_domain *parent);
> >  u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev);
> >  struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev);
> > +void pci_msix_prepare_desc(struct irq_domain *domain, msi_alloc_info_t *arg,
> > +			   struct msi_desc *desc);
> >  #else /* CONFIG_PCI_MSI */
> >  static inline struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev)
> >  {
> > -- 
> > 2.34.1
> >

Patchew 2.1-devel-b67e4c2

© 2016 - 2026 Red Hat, Inc.