Hi Markus,
On 22/09/2016 17:42, Markus Armbruster wrote:
> Eric Auger <eric.au...@redhat.com> writes:
>
>> To prepare for migration to realize, let's use a local error
>> object in vfio_initfn. Also let's use the same error prefix for all
>> error messages.
>>
>> On top of the 1-1 conversion, we start using a common error prefix for
>> all error messages. We also introduce a similar warning prefix which will
>> be used later on.
>>
>> Signed-off-by: Eric Auger <eric.au...@redhat.com>
>> ---
>>
>> v2: creation
>> ---
>> hw/vfio/pci.c | 73
>> +++++++++++++++++++++++++------------------
>> include/hw/vfio/vfio-common.h | 3 ++
>> 2 files changed, 46 insertions(+), 30 deletions(-)
>>
>> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
>> index a5a620a..ca0293d 100644
>> --- a/hw/vfio/pci.c
>> +++ b/hw/vfio/pci.c
>> @@ -2493,6 +2493,7 @@ static int vfio_initfn(PCIDevice *pdev)
>> VFIODevice *vbasedev_iter;
>> VFIOGroup *group;
>> char *tmp, group_path[PATH_MAX], *group_name;
>> + Error *err = NULL;
>> ssize_t len;
>> struct stat st;
>> int groupid;
>> @@ -2506,9 +2507,9 @@ static int vfio_initfn(PCIDevice *pdev)
>> }
>>
>> if (stat(vdev->vbasedev.sysfsdev, &st) < 0) {
>> - error_report("vfio: error: no such host device: %s",
>> - vdev->vbasedev.sysfsdev);
>> - return -errno;
>> + error_setg(&err, "no such host device");
>
> Any particular reason you don't use error_setg_errno() here?
I hesitated and eventually removed into thinking it was not bringing
much value. But not strong opinion here, I will restore it.
>
>> + ret = -errno;
>> + goto error;
>> }
>>
>> vdev->vbasedev.name = g_strdup(basename(vdev->vbasedev.sysfsdev));
>> @@ -2520,40 +2521,44 @@ static int vfio_initfn(PCIDevice *pdev)
>> g_free(tmp);
>>
>> if (len <= 0 || len >= sizeof(group_path)) {
>> - error_report("vfio: error no iommu_group for device");
>> - return len < 0 ? -errno : -ENAMETOOLONG;
>> + error_setg_errno(&err, len < 0 ? errno : ENAMETOOLONG,
>> + "no iommu_group found");
>> + ret = len < 0 ? -errno : -ENAMETOOLONG;
>
> Suggest
>
> ret = len < 0 ? -errno : -ENAMETOOLONG;
> error_setg_errno(&err, -ret, "no iommu_group found");
Sure. Eventually ret will disappear so we will come back to
error_setg_errno(&err, len < 0 ? errno : ENAMETOOLONG,
>> + "no iommu_group found");
>
>> + goto error;
>> }
>>
>> group_path[len] = 0;
>>
>> group_name = basename(group_path);
>> if (sscanf(group_name, "%d", &groupid) != 1) {
>> - error_report("vfio: error reading %s: %m", group_path);
>> - return -errno;
>> + error_setg_errno(&err, errno, "failed to read %s", group_path);
>> + ret = -errno;
>> + goto error;
>> }
>>
>> trace_vfio_initfn(vdev->vbasedev.name, groupid);
>>
>> group = vfio_get_group(groupid, pci_device_iommu_address_space(pdev));
>> if (!group) {
>> - error_report("vfio: failed to get group %d", groupid);
>> - return -ENOENT;
>> + error_setg(&err, "failed to get group %d", groupid);
>> + ret = -ENOENT;
>> + goto error;
>> }
>>
>> QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
>> if (strcmp(vbasedev_iter->name, vdev->vbasedev.name) == 0) {
>> - error_report("vfio: error: device %s is already attached",
>> - vdev->vbasedev.name);
>> + error_setg(&err, "device is already attached");
>> vfio_put_group(group);
>> - return -EBUSY;
>> + ret = -EBUSY;
>> + goto error;
>> }
>> }
>>
>> ret = vfio_get_device(group, vdev->vbasedev.name, &vdev->vbasedev);
>> if (ret) {
>> - error_report("vfio: failed to get device %s", vdev->vbasedev.name);
>> + error_setg_errno(&err, -ret, "failed to get device");
>> vfio_put_group(group);
>> - return ret;
>> + goto error;
>> }
>>
>> ret = vfio_populate_device(vdev);
>> @@ -2567,8 +2572,8 @@ static int vfio_initfn(PCIDevice *pdev)
>> vdev->config_offset);
>> if (ret < (int)MIN(pci_config_size(&vdev->pdev), vdev->config_size)) {
>> ret = ret < 0 ? -errno : -EFAULT;
>> - error_report("vfio: Failed to read device config space");
>> - return ret;
>> + error_setg_errno(&err, -ret, "failed to read device config space");
>> + goto error;
>> }
>>
>> /* vfio emulates a lot for us, but some bits need extra love */
>> @@ -2584,8 +2589,9 @@ static int vfio_initfn(PCIDevice *pdev)
>> */
>> if (vdev->vendor_id != PCI_ANY_ID) {
>> if (vdev->vendor_id >= 0xffff) {
>> - error_report("vfio: Invalid PCI vendor ID provided");
>> - return -EINVAL;
>> + error_setg(&err, "invalid PCI vendor ID provided");
>> + ret = -EINVAL;
>> + goto error;
>> }
>> vfio_add_emulated_word(vdev, PCI_VENDOR_ID, vdev->vendor_id, ~0);
>> trace_vfio_pci_emulated_vendor_id(vdev->vbasedev.name,
>> vdev->vendor_id);
>> @@ -2595,8 +2601,9 @@ static int vfio_initfn(PCIDevice *pdev)
>>
>> if (vdev->device_id != PCI_ANY_ID) {
>> if (vdev->device_id > 0xffff) {
>> - error_report("vfio: Invalid PCI device ID provided");
>> - return -EINVAL;
>> + error_setg(&err, "invalid PCI device ID provided");
>> + ret = -EINVAL;
>> + goto error;
>> }
>> vfio_add_emulated_word(vdev, PCI_DEVICE_ID, vdev->device_id, ~0);
>> trace_vfio_pci_emulated_device_id(vdev->vbasedev.name,
>> vdev->device_id);
>> @@ -2606,8 +2613,9 @@ static int vfio_initfn(PCIDevice *pdev)
>>
>> if (vdev->sub_vendor_id != PCI_ANY_ID) {
>> if (vdev->sub_vendor_id > 0xffff) {
>> - error_report("vfio: Invalid PCI subsystem vendor ID provided");
>> - return -EINVAL;
>> + error_setg(&err, "invalid PCI subsystem vendor ID provided");
>> + ret = -EINVAL;
>> + goto error;
>> }
>> vfio_add_emulated_word(vdev, PCI_SUBSYSTEM_VENDOR_ID,
>> vdev->sub_vendor_id, ~0);
>> @@ -2617,8 +2625,9 @@ static int vfio_initfn(PCIDevice *pdev)
>>
>> if (vdev->sub_device_id != PCI_ANY_ID) {
>> if (vdev->sub_device_id > 0xffff) {
>> - error_report("vfio: Invalid PCI subsystem device ID provided");
>> - return -EINVAL;
>> + error_setg(&err, "invalid PCI subsystem device ID provided");
>> + ret = -EINVAL;
>> + goto error;
>> }
>> vfio_add_emulated_word(vdev, PCI_SUBSYSTEM_ID, vdev->sub_device_id,
>> ~0);
>> trace_vfio_pci_emulated_sub_device_id(vdev->vbasedev.name,
>> @@ -2671,8 +2680,9 @@ static int vfio_initfn(PCIDevice *pdev)
>> struct vfio_region_info *opregion;
>>
>> if (vdev->pdev.qdev.hotplugged) {
>> - error_report("Cannot support IGD OpRegion feature on hotplugged
>> "
>> - "device %s", vdev->vbasedev.name);
>> + error_setg(&err,
>> + "cannot support IGD OpRegion feature on hotplugged "
>> + "device");
>> ret = -EINVAL;
>> goto out_teardown;
>> }
>> @@ -2681,16 +2691,15 @@ static int vfio_initfn(PCIDevice *pdev)
>> VFIO_REGION_TYPE_PCI_VENDOR_TYPE |
>> PCI_VENDOR_ID_INTEL,
>> VFIO_REGION_SUBTYPE_INTEL_IGD_OPREGION, &opregion);
>> if (ret) {
>> - error_report("Device %s does not support requested IGD OpRegion
>> "
>> - "feature", vdev->vbasedev.name);
>> + error_setg_errno(&err, -ret,
>> + "does not support requested IGD OpRegion
>> feature");
>> goto out_teardown;
>> }
>>
>> ret = vfio_pci_igd_opregion_init(vdev, opregion);
>> g_free(opregion);
>> if (ret) {
>> - error_report("Device %s IGD OpRegion initialization failed",
>> - vdev->vbasedev.name);
>> + error_setg_errno(&err, -ret, "IGD OpRegion initialization
>> failed");
>> goto out_teardown;
>> }
>> }
>> @@ -2726,6 +2735,10 @@ out_teardown:
>> pci_device_set_intx_routing_notifier(&vdev->pdev, NULL);
>> vfio_teardown_msi(vdev);
>> vfio_bars_exit(vdev);
>> +error:
>> + if (err) {
>> + error_reportf_err(err, ERR_PREFIX, vdev->vbasedev.name);
>> + }
>> return ret;
>> }
>
> The value assigned to ret doesn't matter as long as it's negative, which
> makes me wonder why we bother with different values here. Peeking
> ahead, I see you simplify this already as part of your conversion to
> realize(). Okay, that works for me.
At that stage it was a 1-1 conversion. Indeed this eventually disappears.
>
>>
>> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
>> index 94dfae3..fd19880 100644
>> --- a/include/hw/vfio/vfio-common.h
>> +++ b/include/hw/vfio/vfio-common.h
>> @@ -30,6 +30,9 @@
>> #include <linux/vfio.h>
>> #endif
>>
>> +#define ERR_PREFIX "vfio error: %s: "
>> +#define WARN_PREFIX "vfio warning: %s: "
>> +
>> /*#define DEBUG_VFIO*/
>> #ifdef DEBUG_VFIO
>> #define DPRINTF(fmt, ...) \
>
> We already discussed error message prefixes and errno strings. I got my
> taste, you got yours. Since this is your code, yours wins :)
>
Here is a sample output. Using qmp interactively you easily get to know
which device BDF produced the error. Also qemu prints the -device option
which lead to the error.
(QEMU) device_add driver=vfio-pci host=0000:01:10.0 bus=head.2 addr=0x14
{"error": {"class": "GenericError", "desc": "vfio error: 0000:01:10.0:
error opening /dev/vfio/6: No such file or directory"}}
qemu-system-aarch64: -device vfio-pci,host=0000:01:10.0: vfio error:
0000:01:10.0: error opening /dev/vfio/6: No such file or directory
However in case of more complex usage (qmp scripts?), might be helpful
to get the BDF directly in the error output?
Thanks
Eric
