Re: [Qemu-devel] [PATCH 3/3] vfio/pci: pass an error object to vfio_msix_early_setup

[Markus Armbruster <armbru@redhat.com>]

Eric Auger <eric.auger@redhat.com> writes:

> Let's expand the usage of QEMU Error objects to vfio_msix_early_setup.
>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> ---
>  hw/vfio/pci.c | 28 ++++++++++++++++------------
>  1 file changed, 16 insertions(+), 12 deletions(-)
>
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index f7768e9..b132bf1 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -1275,7 +1275,7 @@ static void vfio_pci_fixup_msix_region(VFIOPCIDevice *vdev)
>   * need to first look for where the MSI-X table lives.  So we
>   * unfortunately split MSI-X setup across two functions.
>   */
> -static int vfio_msix_early_setup(VFIOPCIDevice *vdev)
> +static void vfio_msix_early_setup(VFIOPCIDevice *vdev, Error **errp)
>  {
>      uint8_t pos;
>      uint16_t ctrl;
> @@ -1285,22 +1285,25 @@ static int vfio_msix_early_setup(VFIOPCIDevice *vdev)
>  
>      pos = pci_find_capability(&vdev->pdev, PCI_CAP_ID_MSIX);
>      if (!pos) {
> -        return 0;
> +        return;
>      }
>  
>      if (pread(fd, &ctrl, sizeof(ctrl),
>                vdev->config_offset + pos + PCI_MSIX_FLAGS) != sizeof(ctrl)) {
> -        return -errno;
> +        error_setg_errno(errp, -errno, "failed to read PCI MSIX FLAGS");
> +        return;

Looks like a bug fix to me: before your series, this is a silent
failure.  PATCH 1 makes it non-silent, with a generic error message, and
this patch replaces it with a specific error message.

>      }
>  
>      if (pread(fd, &table, sizeof(table),
>                vdev->config_offset + pos + PCI_MSIX_TABLE) != sizeof(table)) {
> -        return -errno;
> +        error_setg_errno(errp, -errno, "failed to read PCI MSIX TABLE");
> +        return;

Likewise.

>      }
>  
>      if (pread(fd, &pba, sizeof(pba),
>                vdev->config_offset + pos + PCI_MSIX_PBA) != sizeof(pba)) {
> -        return -errno;
> +        error_setg_errno(errp, -errno, "failed to read PCI MSIX PBA");
> +        return;

Likewise.

>      }
>  
>      ctrl = le16_to_cpu(ctrl);
> @@ -1330,10 +1333,11 @@ static int vfio_msix_early_setup(VFIOPCIDevice *vdev)
>              (vdev->device_id & 0xff00) == 0x5800) {
>              msix->pba_offset = 0x1000;
>          } else {
> -            error_report("vfio: Hardware reports invalid configuration, "
> -                         "MSIX PBA outside of specified BAR");
> +            error_setg_errno(errp, -EINVAL,
> +                       "hardware reports invalid configuration, "
> +                       "MSIX PBA outside of specified BAR");
>              g_free(msix);
> -            return -EINVAL;
> +            return;
>          }
>      }
>  
> @@ -1343,7 +1347,7 @@ static int vfio_msix_early_setup(VFIOPCIDevice *vdev)
>  
>      vfio_pci_fixup_msix_region(vdev);
>  
> -    return 0;
> +    return;
>  }
>  
>  static int vfio_msix_setup(VFIOPCIDevice *vdev, int pos)
> @@ -2642,9 +2646,9 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
>  
>      vfio_pci_size_rom(vdev);
>  
> -    ret = vfio_msix_early_setup(vdev);
> -    if (ret) {
> -        error_setg_errno(errp, ret, "msix early setup failure");
> +    vfio_msix_early_setup(vdev, &err);
> +    if (err) {
> +        error_propagate(errp, err);
>          goto error;
>      }

vfio_realize() still calls a few functions that report errors with
error_report(), including vfio_get_group(), vfio_get_device(),
vfio_pci_igd_opregion_init(), vfio_intx_enable().  If you prefer not to
complete the job right now, please mark such calls FIXME.