On Thu, 27 Jul 2023 03:24:08 -0400
Jing Liu <jing2....@intel.com> wrote:
> From: Reinette Chatre <reinette.cha...@intel.com>
>
> Kernel provides the guidance of dynamic MSI-X allocation support of
> passthrough device, by clearing the VFIO_IRQ_INFO_NORESIZE flag to
> guide user space.
>
> Fetch and store the flags from host for later use to determine if
> specific flags are set.
>
> Signed-off-by: Reinette Chatre <reinette.cha...@intel.com>
> Signed-off-by: Jing Liu <jing2....@intel.com>
> ---
> hw/vfio/pci.c | 12 ++++++++++++
> hw/vfio/pci.h | 1 +
> hw/vfio/trace-events | 2 ++
> 3 files changed, 15 insertions(+)
>
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index a205c6b1130f..0c4ac0873d40 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -1572,6 +1572,7 @@ static void vfio_msix_early_setup(VFIOPCIDevice *vdev,
> Error **errp)
>
> static int vfio_msix_setup(VFIOPCIDevice *vdev, int pos, Error **errp)
> {
> + struct vfio_irq_info irq_info = { .argsz = sizeof(irq_info) };
> int ret;
> Error *err = NULL;
>
> @@ -1624,6 +1625,17 @@ static int vfio_msix_setup(VFIOPCIDevice *vdev, int
> pos, Error **errp)
> memory_region_set_enabled(&vdev->pdev.msix_table_mmio, false);
> }
>
> + irq_info.index = VFIO_PCI_MSIX_IRQ_INDEX;
> + ret = ioctl(vdev->vbasedev.fd, VFIO_DEVICE_GET_IRQ_INFO, &irq_info);
> + if (ret) {
> + /* This can fail for an old kernel or legacy PCI dev */
> + trace_vfio_msix_setup_get_irq_info_failure(strerror(errno));
We only call vfio_msix_setup() if the device has an MSI-X capability,
so the "legacy PCI" portion of this comment seems unjustified.
Otherwise the GET_IRQ_INFO ioctl has always existed, so I'd also
question the "old kernel" part of this comment. We don't currently
sanity test the device exposed MSI-X info versus that reported by
GET_IRQ_INFO, but it seems valid to do so. I'd expect this to happen
in vfio_msix_early_setup() though, especially since that's where the
remainder of VFIOMSIXInfo is setup.
> + } else {
> + vdev->msix->irq_info_flags = irq_info.flags;
> + }
> + trace_vfio_msix_setup_irq_info_flags(vdev->vbasedev.name,
> + vdev->msix->irq_info_flags);
> +
> return 0;
> }
>
> diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
> index a2771b9ff3cc..ad34ec56d0ae 100644
> --- a/hw/vfio/pci.h
> +++ b/hw/vfio/pci.h
> @@ -113,6 +113,7 @@ typedef struct VFIOMSIXInfo {
> uint32_t table_offset;
> uint32_t pba_offset;
> unsigned long *pending;
> + uint32_t irq_info_flags;
Why not simply pull out a "noresize" bool? Thanks,
Alex
> } VFIOMSIXInfo;
>
> #define TYPE_VFIO_PCI "vfio-pci"
> diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
> index ee7509e68e4f..7d4a398f044d 100644
> --- a/hw/vfio/trace-events
> +++ b/hw/vfio/trace-events
> @@ -28,6 +28,8 @@ vfio_pci_read_config(const char *name, int addr, int len,
> int val) " (%s, @0x%x,
> vfio_pci_write_config(const char *name, int addr, int val, int len) " (%s,
> @0x%x, 0x%x, len=0x%x)"
> vfio_msi_setup(const char *name, int pos) "%s PCI MSI CAP @0x%x"
> vfio_msix_early_setup(const char *name, int pos, int table_bar, int offset,
> int entries) "%s PCI MSI-X CAP @0x%x, BAR %d, offset 0x%x, entries %d"
> +vfio_msix_setup_get_irq_info_failure(const char *errstr)
> "VFIO_DEVICE_GET_IRQ_INFO failure: %s"
> +vfio_msix_setup_irq_info_flags(const char *name, uint32_t flags) " (%s)
> MSI-X irq info flags 0x%x"
> vfio_check_pcie_flr(const char *name) "%s Supports FLR via PCIe cap"
> vfio_check_pm_reset(const char *name) "%s Supports PM reset"
> vfio_check_af_flr(const char *name) "%s Supports FLR via AF cap"
