Re: [Qemu-devel] [PATCH v2 04/11] vfio: add aer support for vfio device

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

On Mon, 7 Mar 2016 11:22:57 +0800
Cao jin <caoj.fnst@cn.fujitsu.com> wrote:

> From: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
> 
> Calling pcie_aer_init to initilize aer related registers for
> vfio device, then reload physical related registers to expose
> device capability.
> 
> Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
> ---
>  hw/vfio/pci.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
>  hw/vfio/pci.h |  3 +++
>  2 files changed, 81 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index e64cce3..8ec9b25 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -1868,6 +1868,62 @@ static int vfio_add_std_cap(VFIOPCIDevice *vdev, uint8_t pos)
>      return 0;
>  }
>  
> +static int vfio_setup_aer(VFIOPCIDevice *vdev, uint8_t cap_ver,
> +                          int pos, uint16_t size)
> +{
> +    PCIDevice *pdev = &vdev->pdev;
> +    PCIDevice *dev_iter;
> +    uint8_t type;
> +    uint32_t errcap;
> +
> +    if (!(vdev->features & VFIO_FEATURE_ENABLE_AER)) {
> +        pcie_add_capability(pdev, PCI_EXT_CAP_ID_ERR,
> +                            cap_ver, pos, size);
> +        return 0;
> +    }
> +
> +    dev_iter = pci_bridge_get_device(pdev->bus);
> +    if (!dev_iter) {
> +        goto error;
> +    }
> +
> +    while (dev_iter) {
> +        type = pcie_cap_get_type(dev_iter);

This asserts if dev_iter doesn't have an express capability so do we
really ever get to the error goto in practice?  I think an average user
is going to get more information from your error_report than from an
assert.  Thanks,

Alex

> +        if ((type != PCI_EXP_TYPE_ROOT_PORT &&
> +             type != PCI_EXP_TYPE_UPSTREAM &&
> +             type != PCI_EXP_TYPE_DOWNSTREAM)) {
> +            goto error;
> +        }
> +
> +        if (!dev_iter->exp.aer_cap) {
> +            goto error;
> +        }
> +
> +        dev_iter = pci_bridge_get_device(dev_iter->bus);
> +    }
> +
> +    errcap = vfio_pci_read_config(pdev, pos + PCI_ERR_CAP, 4);
> +    /*
> +     * The ability to record multiple headers is depending on
> +     * the state of the Multiple Header Recording Capable bit and
> +     * enabled by the Multiple Header Recording Enable bit.
> +     */
> +    if ((errcap & PCI_ERR_CAP_MHRC) &&
> +        (errcap & PCI_ERR_CAP_MHRE)) {
> +        pdev->exp.aer_log.log_max = PCIE_AER_LOG_MAX_DEFAULT;
> +    } else {
> +        pdev->exp.aer_log.log_max = 0;
> +    }
> +
> +    pcie_cap_deverr_init(pdev);
> +    return pcie_aer_init(pdev, pos, size);
> +
> +error:
> +    error_report("vfio: Unable to enable AER for device %s, parent bus "
> +                 "does not support AER signaling", vdev->vbasedev.name);
> +    return -1;
> +}
> +
>  static int vfio_add_ext_cap(VFIOPCIDevice *vdev)
>  {
>      PCIDevice *pdev = &vdev->pdev;
> @@ -1875,6 +1931,7 @@ static int vfio_add_ext_cap(VFIOPCIDevice *vdev)
>      uint16_t cap_id, next, size;
>      uint8_t cap_ver;
>      uint8_t *config;
> +    int ret = 0;
>  
>      /*
>       * pcie_add_capability always inserts the new capability at the tail
> @@ -1898,16 +1955,29 @@ static int vfio_add_ext_cap(VFIOPCIDevice *vdev)
>           */
>          size = vfio_ext_cap_max_size(config, next);
>  
> -        pcie_add_capability(pdev, cap_id, cap_ver, next, size);
> -        pci_set_long(dev->config + next, PCI_EXT_CAP(cap_id, cap_ver, 0));
> +        switch (cap_id) {
> +        case PCI_EXT_CAP_ID_ERR:
> +            ret = vfio_setup_aer(vdev, cap_ver, next, size);
> +            break;
> +        default:
> +            pcie_add_capability(pdev, cap_id, cap_ver, next, size);
> +            break;
> +        }
> +
> +        if (ret) {
> +            goto out;
> +        }
> +
> +        pci_set_long(pdev->config + next, PCI_EXT_CAP(cap_id, cap_ver, 0));
>  
>          /* Use emulated next pointer to allow dropping extended caps */
>          pci_long_test_and_set_mask(vdev->emulated_config_bits + next,
>                                     PCI_EXT_CAP_NEXT_MASK);
>      }
>  
> +out:
>      g_free(config);
> -    return 0;
> +    return ret;
>  }
>  
>  static int vfio_add_capabilities(VFIOPCIDevice *vdev)
> @@ -2662,6 +2732,11 @@ static int vfio_initfn(PCIDevice *pdev)
>          goto out_teardown;
>      }
>  
> +    if ((vdev->features & VFIO_FEATURE_ENABLE_AER) &&
> +        !pdev->exp.aer_cap) {
> +        goto out_teardown;
> +    }
> +
>      /* QEMU emulates all of MSI & MSIX */
>      if (pdev->cap_present & QEMU_PCI_CAP_MSIX) {
>          memset(vdev->emulated_config_bits + pdev->msix_cap, 0xff,
> diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
> index 6256587..e0c53f2 100644
> --- a/hw/vfio/pci.h
> +++ b/hw/vfio/pci.h
> @@ -15,6 +15,7 @@
>  #include "qemu-common.h"
>  #include "exec/memory.h"
>  #include "hw/pci/pci.h"
> +#include "hw/pci/pci_bridge.h"
>  #include "hw/vfio/vfio-common.h"
>  #include "qemu/event_notifier.h"
>  #include "qemu/queue.h"
> @@ -128,6 +129,8 @@ typedef struct VFIOPCIDevice {
>  #define VFIO_FEATURE_ENABLE_VGA (1 << VFIO_FEATURE_ENABLE_VGA_BIT)
>  #define VFIO_FEATURE_ENABLE_REQ_BIT 1
>  #define VFIO_FEATURE_ENABLE_REQ (1 << VFIO_FEATURE_ENABLE_REQ_BIT)
> +#define VFIO_FEATURE_ENABLE_AER_BIT 2
> +#define VFIO_FEATURE_ENABLE_AER (1 << VFIO_FEATURE_ENABLE_AER_BIT)
>      int32_t bootindex;
>      uint8_t pm_cap;
>      bool has_vga;