Re: [Qemu-devel] [RFC v2 2/8] vfio-pci: add aer capability support

[Alex Williamson <alex.williamson@redhat.com>]

On Wed, 2015-01-28 at 16:37 +0800, Chen Fan wrote:
> if we detect the aer capability in vfio device, then
> we should initialize the vfio device aer rigister bits.
> so guest OS can set this bits as needed.

s/rigister/register/

> Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
> ---
>  hw/vfio/pci.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 72 insertions(+)
> 
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index 014a92c..2072261 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -2670,6 +2670,73 @@ static int vfio_add_capabilities(VFIOPCIDevice *vdev)
>      return vfio_add_std_cap(vdev, pdev->config[PCI_CAPABILITY_LIST]);
>  }
>  
> +static void vfio_pci_aer_init(VFIOPCIDevice *vdev)
> +{
> +    PCIDevice *pdev = &vdev->pdev;
> +    PCIExpressDevice *exp = &pdev->exp;
> +    uint16_t offset = exp->aer_cap;
> +
> +    if (!offset) {
> +        return;
> +    }
> +

All of these need to be documented with comments.

> +    memset(pdev->wmask + offset, 0, PCI_ERR_SIZEOF);
> +    memset(pdev->w1cmask + offset, 0, PCI_ERR_SIZEOF);
> +    memset(pdev->cmask + offset, 0xFF, PCI_ERR_SIZEOF);
> +
> +    pci_long_test_and_set_mask(pdev->wmask + exp->exp_cap + PCI_EXP_DEVCTL,
> +                               PCI_EXP_DEVCTL_CERE | PCI_EXP_DEVCTL_NFERE |
> +                               PCI_EXP_DEVCTL_FERE | PCI_EXP_DEVCTL_URRE);
> +    pci_long_test_and_set_mask(pdev->w1cmask + exp->exp_cap + PCI_EXP_DEVSTA,
> +                               PCI_EXP_DEVSTA_CED | PCI_EXP_DEVSTA_NFED |
> +                               PCI_EXP_DEVSTA_FED | PCI_EXP_DEVSTA_URD);
> +
> +    pci_set_long(pdev->w1cmask + offset + PCI_ERR_UNCOR_STATUS,
> +                 PCI_ERR_UNC_SUPPORTED);
> +    pci_set_long(pdev->wmask + offset + PCI_ERR_UNCOR_SEVER,
> +                 PCI_ERR_UNC_SUPPORTED);
> +    pci_long_test_and_set_mask(pdev->w1cmask + offset + PCI_ERR_COR_STATUS,
> +                               PCI_ERR_COR_STATUS);
> +    pci_set_long(pdev->wmask + offset + PCI_ERR_COR_MASK,
> +                 PCI_ERR_COR_SUPPORTED);
> +
> +    pci_set_long(pdev->wmask + offset + PCI_ERR_CAP,
> +                 PCI_ERR_CAP_ECRC_GENE | PCI_ERR_CAP_ECRC_CHKE |
> +                 PCI_ERR_CAP_MHRE);
> +}
> +
> +static int vfio_add_ext_capabilities(VFIOPCIDevice *vdev)
> +{
> +    PCIDevice *pdev = &vdev->pdev;
> +    PCIExpressDevice *exp;
> +    uint32_t header;
> +    uint16_t next = PCI_CONFIG_SPACE_SIZE;
> +
> +    if (pci_config_size(pdev) <= PCI_CONFIG_SPACE_SIZE) {
> +        return 0;
> +    }
> +
> +    header = pci_get_long(pdev->config + next);
> +    while (header) {
> +        switch (PCI_EXT_CAP_ID(header)) {
> +        case PCI_EXT_CAP_ID_ERR:
> +             exp = &pdev->exp;
> +             exp->aer_cap = next;

Shouldn't we call pcie_aer_init() here?

> +
> +             vfio_pci_aer_init(vdev);
> +             break;
> +        };
> +
> +        next = PCI_EXT_CAP_NEXT(header);
> +        if (!next) {
> +            return 0;
> +        }
> +        header = pci_get_long(pdev->config + next);

I'd like to see this look more like vfio_add_std_cap(), registering
every capability with the QEMU PCIe-core and setting up emulation to
allow QEMU to skip capabilities that it doesn't want to expose.

> +    }
> +
> +    return 0;
> +}
> +
>  static void vfio_pci_pre_reset(VFIOPCIDevice *vdev)
>  {
>      PCIDevice *pdev = &vdev->pdev;
> @@ -3296,6 +3363,11 @@ static int vfio_initfn(PCIDevice *pdev)
>          goto out_teardown;
>      }
>  
> +    ret = vfio_add_ext_capabilities(vdev);
> +    if (ret) {
> +        goto out_teardown;
> +    }
> +

Why not extend vfio_add_capabilities()?  It specifically calls
vfio_add_std_cap() in order that there could be a vfio_add_ext_cap().

>      /* QEMU emulates all of MSI & MSIX */
>      if (pdev->cap_present & QEMU_PCI_CAP_MSIX) {
>          memset(vdev->emulated_config_bits + pdev->msix_cap, 0xff,