Re: [Qemu-devel] [PATCH v16 13/14] vfio-pci: pass the aer error to guest

[Marcel Apfelbaum]

On 01/12/2016 04:43 AM, Cao jin wrote:
> From: Chen Fan <address@hidden>
>
> when the vfio device encounters an uncorrectable error in host,
> the vfio_pci driver will signal the eventfd registered by this
> vfio device, the results in the qemu eventfd handler getting

Maybe "the results in" -> resulting in

> invoked.
>
> this patch is to pass the error to guest and have the guest driver
> recover from the error.

Maybe "Pass the error to... and let the ... "

> Signed-off-by: Chen Fan <address@hidden>
> ---
>   hw/vfio/pci.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++------
>   1 file changed, 47 insertions(+), 6 deletions(-)
>
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index da4815e..efa5e01 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -2553,18 +2553,59 @@ static void vfio_put_device(VFIOPCIDevice *vdev)
>   static void vfio_err_notifier_handler(void *opaque)
>   {
>       VFIOPCIDevice *vdev = opaque;
> +    PCIDevice *dev = &vdev->pdev;
> +    PCIEAERMsg msg = {
> +        .severity = 0,
> +        .source_id = (pci_bus_num(dev->bus) << 8) | dev->devfn,
> +    };
>
>       if (!event_notifier_test_and_clear(&vdev->err_notifier)) {
>           return;
>       }
>
>       /*
> -     * TBD. Retrieve the error details and decide what action
> -     * needs to be taken. One of the actions could be to pass
> -     * the error to the guest and have the guest driver recover
> -     * from the error. This requires that PCIe capabilities be
> -     * exposed to the guest. For now, we just terminate the
> -     * guest to contain the error.
> +     * in case the real hardware configration has been changed,

configration -> configuration


> +     * here we should recheck the bus reset capability.
> +     */
> +    if ((vdev->features & VFIO_FEATURE_ENABLE_AER) &&
> +        vfio_check_host_bus_reset(vdev)) {
> +        goto stop;
> +    }
> +    /*
> +     * we should read the error details from the real hardware
> +     * configuration spaces, here we only need to do is signaling
> +     * to guest an uncorrectable error has occurred.
> +     */
> +    if ((vdev->features & VFIO_FEATURE_ENABLE_AER) &&
> +        dev->exp.aer_cap) {

Why do we need dev->exp.aer_cap check here? In patch 7/14 we fail the device 
init
process if this happens, right?

> +        uint8_t *aer_cap = dev->config + dev->exp.aer_cap;
> +        uint32_t uncor_status;
> +        bool isfatal;
> +
> +        uncor_status = vfio_pci_read_config(dev,
> +                           dev->exp.aer_cap + PCI_ERR_UNCOR_STATUS, 4);
> +
> +        /*
> +         * if we receive the error signal but not this device, we can

maybe "if the error is not emitted by this device..."


Thanks,
Marcel

> +         * just ignore it.
> +         */
> +        if (!(uncor_status & ~0UL)) {
> +            return;
> +        }
> +
> +        isfatal = uncor_status & pci_get_long(aer_cap + PCI_ERR_UNCOR_SEVER);
> +
> +        msg.severity = isfatal ? PCI_ERR_ROOT_CMD_FATAL_EN :
> +                                 PCI_ERR_ROOT_CMD_NONFATAL_EN;
> +
> +        pcie_aer_msg(dev, &msg);
> +        return;
> +    }
> +
> +stop:
> +    /*
> +     * If the aer capability is not exposed to the guest. we just
> +     * terminate the guest to contain the error.
>        */
>
>       error_report("%s(%04x:%02x:%02x.%x) Unrecoverable error detected.  "