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

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

On Fri, 2015-02-06 at 15:03 +0800, Chen Fan wrote:
> On 02/03/2015 04:15 AM, Alex Williamson wrote:
> > 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?
> I am afraid pcie_aer_init() maybe impact the corresponding values
> in pdev->config.

Then we should do cleanup after calling pcie_aer_init() or modify
pcie_aer_init() to do what we need.  Doing raw aer manipulation outside
of core support just causes maintenance issues down the road.  Thanks,

Alex

> >> +
> >> +             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().
> it is a good idea.
> 
> Thanks,
> Chen
> 
> 
> >
> >>       /* QEMU emulates all of MSI & MSIX */
> >>       if (pdev->cap_present & QEMU_PCI_CAP_MSIX) {
> >>           memset(vdev->emulated_config_bits + pdev->msix_cap, 0xff,
> >
> >
> > .
> >
>