On Wed, Apr 16, 2025 at 01:30:42PM -0500, Bjorn Helgaas wrote:
> [+to Thomas]
>
> On Wed, Apr 16, 2025 at 08:36:06AM -0700, Shradha Gupta wrote:
> > For supporting dynamic MSI 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 needed. Export pci_msix_prepare_desc() to allow pci
> > controllers like pci-hyperv to support dynamic MSI vector allocation.
> > Also, add the flag MSI_FLAG_PCI_MSIX_ALLOC_DYN and use
> > pci_msix_prepare_desc() in pci_hyperv controller
>
> Follow capitalization convention for subject line. Probably remove
> "pci_hyperv" since it already contains "PCI: hv" and add something
> about MSI-X.
>
> s/pci/PCI/
>
> s/MSI vector/MSI-X vector/ since the context says you're concerned
> with MSI-X.
>
> This requires an ack from Thomas; moved him to "To:" line.
>
Thanks Bjorn. I will work on addressing these.
Regards,
Shradha.
> > Signed-off-by: Shradha Gupta <shradhagu...@linux.microsoft.com>
> > Reviewed-by: Haiyang Zhang <haiya...@microsoft.com>
> > Reviewed-by: Long Li <lon...@microsoft.com>
> > ---
> > drivers/pci/controller/pci-hyperv.c | 7 +++++--
> > drivers/pci/msi/irqdomain.c | 5 +++--
> > include/linux/msi.h | 2 ++
> > 3 files changed, 10 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/pci/controller/pci-hyperv.c
> > b/drivers/pci/controller/pci-hyperv.c
> > index ac27bda5ba26..f2fa6bdb6bb8 100644
> > --- a/drivers/pci/controller/pci-hyperv.c
> > +++ b/drivers/pci/controller/pci-hyperv.c
> > @@ -598,7 +598,8 @@ static unsigned int hv_msi_get_int_vector(struct
> > irq_data *data)
> > return cfg->vector;
> > }
> >
> > -#define hv_msi_prepare pci_msi_prepare
> > +#define hv_msi_prepare pci_msi_prepare
> > +#define hv_msix_prepare_desc pci_msix_prepare_desc
> >
> > /**
> > * hv_arch_irq_unmask() - "Unmask" the IRQ by setting its current
> > @@ -727,6 +728,7 @@ static void hv_arch_irq_unmask(struct irq_data *data)
> > #define FLOW_HANDLER NULL
> > #define FLOW_NAME NULL
> > #define hv_msi_prepare NULL
> > +#define hv_msix_prepare_desc NULL
> >
> > struct hv_pci_chip_data {
> > DECLARE_BITMAP(spi_map, HV_PCI_MSI_SPI_NR);
> > @@ -2063,6 +2065,7 @@ static struct irq_chip hv_msi_irq_chip = {
> > static struct msi_domain_ops hv_msi_ops = {
> > .msi_prepare = hv_msi_prepare,
> > .msi_free = hv_msi_free,
> > + .prepare_desc = hv_msix_prepare_desc,
> > };
> >
> > /**
> > @@ -2084,7 +2087,7 @@ static int hv_pcie_init_irq_domain(struct
> > hv_pcibus_device *hbus)
> > hbus->msi_info.ops = &hv_msi_ops;
> > hbus->msi_info.flags = (MSI_FLAG_USE_DEF_DOM_OPS |
> > MSI_FLAG_USE_DEF_CHIP_OPS | MSI_FLAG_MULTI_PCI_MSI |
> > - MSI_FLAG_PCI_MSIX);
> > + MSI_FLAG_PCI_MSIX | MSI_FLAG_PCI_MSIX_ALLOC_DYN);
> > hbus->msi_info.handler = FLOW_HANDLER;
> > hbus->msi_info.handler_name = FLOW_NAME;
> > hbus->msi_info.data = hbus;
> > 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
> >
