On Mon, Apr 28, 2025 at 01:47:22PM +0000, Michael Kelley wrote:
> From: Shradha Gupta <shradhagu...@linux.microsoft.com> Sent: Friday, April
> 25, 2025 3:54 AM
> >
> > 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 descriptors.
>
> I'm unclear from the code below whether the intent is to support dynamic
> allocation only x86, or on both x86 and arm64. On arm64, you've defined
> hv_msi_prepare_desc as NULL, but hv_msi_prepare is also defined as NULL
> on arm64, so I'm not sure what to conclude. MSI_FLAG_PCI_MSIX_ALLOC_DYN
> is being set for both architectures.
>
> In any case, please be explicit about your intent in the commit message.
> If the intent is to not support arm64, why is that?
>
> Michael
Thank you for the comments Michael, in my recent testing on arm64, turns
out this function is indeed needed for the complete support.
I will test this out more thoroughly on arm64 and include the arm64 support
in next version.
Regards,
Shradha.
>
> >
> > Signed-off-by: Shradha Gupta <shradhagu...@linux.microsoft.com>
> > Reviewed-by: Haiyang Zhang <haiya...@microsoft.com>
> > ---
> > 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..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;
> > --
> > 2.34.1
> >
