Allow dynamic MSI-X vector allocation for pci_hyperv PCI controller
by adding support for the flag MSI_FLAG_PCI_MSIX_ALLOC_DYN and using
pci_msix_prepare_desc() to prepare the MSI-X descriptors.

Feature support added for both x86 and ARM64

Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
---
 Changes in v3:
 * Add arm64 support
---
 Changes in v2:
 * split the patch to keep changes in PCI and pci_hyperv controller
   seperate
 * replace strings "pci vectors" by "MSI-X vectors"
---
 drivers/pci/controller/pci-hyperv.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index ac27bda5ba26..8c8882cb0ad2 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	pci_msix_prepare_desc
 
 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;
-- 
2.34.1

On Fri, May 09, 2025 at 03:13:22AM -0700, Shradha Gupta wrote:
> Allow dynamic MSI-X vector allocation for pci_hyperv PCI controller
> by adding support for the flag MSI_FLAG_PCI_MSIX_ALLOC_DYN and using
> pci_msix_prepare_desc() to prepare the MSI-X descriptors.
> 
> Feature support added for both x86 and ARM64
> 
> Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
> ---
>  Changes in v3:
>  * Add arm64 support
> ---
>  Changes in v2:
>  * split the patch to keep changes in PCI and pci_hyperv controller
>    seperate
>  * replace strings "pci vectors" by "MSI-X vectors"
> ---
>  drivers/pci/controller/pci-hyperv.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
> index ac27bda5ba26..8c8882cb0ad2 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

Please do not use custom macro unless its defintion changes based on some
conditional. In this case, you should use pci_msix_prepare_desc directly for
prepare_desc() callback.

- Mani

--
மணிவண்ணன் சதாசிவம்

On Mon, May 12, 2025 at 12:30:04PM +0530, Manivannan Sadhasivam wrote:
> On Fri, May 09, 2025 at 03:13:22AM -0700, Shradha Gupta wrote:
> > Allow dynamic MSI-X vector allocation for pci_hyperv PCI controller
> > by adding support for the flag MSI_FLAG_PCI_MSIX_ALLOC_DYN and using
> > pci_msix_prepare_desc() to prepare the MSI-X descriptors.
> > 
> > Feature support added for both x86 and ARM64
> > 
> > Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
> > Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
> > ---
> >  Changes in v3:
> >  * Add arm64 support
> > ---
> >  Changes in v2:
> >  * split the patch to keep changes in PCI and pci_hyperv controller
> >    seperate
> >  * replace strings "pci vectors" by "MSI-X vectors"
> > ---
> >  drivers/pci/controller/pci-hyperv.c | 7 +++++--
> >  1 file changed, 5 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
> > index ac27bda5ba26..8c8882cb0ad2 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
> 
> Please do not use custom macro unless its defintion changes based on some
> conditional. In this case, you should use pci_msix_prepare_desc directly for
> prepare_desc() callback.
> 
> - Mani
> 
> --
> ??????????????????????????? ????????????????????????

Thanks for catching this Mani, I agree. I will fix this.

regards,
Shradha.