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Re: [Qemu-devel] [PATCH v2 09/12] vfio/pci: Conversion to realize
From: |
Auger Eric |
Subject: |
Re: [Qemu-devel] [PATCH v2 09/12] vfio/pci: Conversion to realize |
Date: |
Fri, 30 Sep 2016 15:34:27 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 |
Hi,
On 22/09/2016 19:24, Markus Armbruster wrote:
> Eric Auger <address@hidden> writes:
>
>> This patch converts VFIO PCI to realize function.
>>
>> Also original initfn errors now are propagated using QEMU
>> error objects. All errors are formatted with the same pattern:
>> "vfio: %s: the error description"
>>
>> Signed-off-by: Eric Auger <address@hidden>
>>
>> ---
>>
>> v1 -> v2:
>> - correct error_setg_errno with positive error values
>> ---
>> hw/vfio/pci.c | 52
>> ++++++++++++++++++++++------------------------------
>> hw/vfio/trace-events | 2 +-
>> 2 files changed, 23 insertions(+), 31 deletions(-)
>>
>> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
>> index 3d43718..857d89f 100644
>> --- a/hw/vfio/pci.c
>> +++ b/hw/vfio/pci.c
>> @@ -2511,7 +2511,7 @@ static void vfio_unregister_req_notifier(VFIOPCIDevice
>> *vdev)
>> vdev->req_enabled = false;
>> }
>>
>> -static int vfio_initfn(PCIDevice *pdev)
>> +static void vfio_realize(PCIDevice *pdev, Error **errp)
>> {
>> VFIOPCIDevice *vdev = DO_UPCAST(VFIOPCIDevice, pdev, pdev);
>> VFIODevice *vbasedev_iter;
>> @@ -2531,9 +2531,9 @@ static int vfio_initfn(PCIDevice *pdev)
>> }
>>
>> if (stat(vdev->vbasedev.sysfsdev, &st) < 0) {
>> - error_setg(&err, "no such host device");
>> - ret = -errno;
>> - goto error;
>> + error_setg(errp, "no such host device");
>> + error_prepend(errp, ERR_PREFIX, vdev->vbasedev.sysfsdev);
>> + return;
>
> Could do
>
> error_setg(errp, "no such host device");
> goto error;
>
> Your choice.
At that stage the vdev->vbasedev.name is not populated yet.
>
>> }
>>
>> vdev->vbasedev.name = g_strdup(basename(vdev->vbasedev.sysfsdev));
>> @@ -2545,9 +2545,8 @@ static int vfio_initfn(PCIDevice *pdev)
>> g_free(tmp);
>>
>> if (len <= 0 || len >= sizeof(group_path)) {
>> - error_setg_errno(&err, len < 0 ? errno : ENAMETOOLONG,
>> + error_setg_errno(errp, len < 0 ? errno : ENAMETOOLONG,
>> "no iommu_group found");
>> - ret = len < 0 ? -errno : -ENAMETOOLONG;
>> goto error;
>> }
>>
>
> Due to this change and others below, ret is no longer valid at the error
> label (fine, it's not used), and the error is set either via err or via
> errp. Works, because error_propagate(errp, err) does the right thing
> then: nothing when err is null. However, changing the goto to jump
> behind the error_propagate when using errp rather than err might be
> clearer.
Let's use a local error when I can't do otherwise then.
>
> Continuing to set the error via err also works. Less churn.
>
> Your choice.
>
>> @@ -2555,24 +2554,21 @@ static int vfio_initfn(PCIDevice *pdev)
>>
>> group_name = basename(group_path);
>> if (sscanf(group_name, "%d", &groupid) != 1) {
>> - error_setg_errno(&err, errno, "failed to read %s", group_path);
>> - ret = -errno;
>> + error_setg_errno(errp, errno, "failed to read %s", group_path);
>> goto error;
>> }
>>
>> - trace_vfio_initfn(vdev->vbasedev.name, groupid);
>> + trace_vfio_realize(vdev->vbasedev.name, groupid);
>>
>> group = vfio_get_group(groupid, pci_device_iommu_address_space(pdev),
>> &err);
>> if (!group) {
>> - ret = -ENOENT;
>> goto error;
>> }
>
> Since you don't examine the error, you could use errp rather than &err.
> Perhaps not worth the churn unless you can get rid of err entirely.
Not possible to completely get rid of local err due to
vfio_pci_igd_opregion_init - since can't dereference errp -but I can do
a local error_propagate.
>
>>
>> QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
>> if (strcmp(vbasedev_iter->name, vdev->vbasedev.name) == 0) {
>> - error_setg(&err, "device is already attached");
>> + error_setg(errp, "device is already attached");
>> vfio_put_group(group);
>> - ret = -EBUSY;
>> goto error;
>> }
>> }
>> @@ -2594,7 +2590,7 @@ 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_setg_errno(&err, -ret, "failed to read device config space");
>> + error_setg_errno(errp, -ret, "failed to read device config space");
>> goto error;
>> }
>>
>> @@ -2611,8 +2607,7 @@ static int vfio_initfn(PCIDevice *pdev)
>> */
>> if (vdev->vendor_id != PCI_ANY_ID) {
>> if (vdev->vendor_id >= 0xffff) {
>> - error_setg(&err, "invalid PCI vendor ID provided");
>> - ret = -EINVAL;
>> + error_setg(errp, "invalid PCI vendor ID provided");
>> goto error;
>> }
>> vfio_add_emulated_word(vdev, PCI_VENDOR_ID, vdev->vendor_id, ~0);
>> @@ -2623,8 +2618,7 @@ static int vfio_initfn(PCIDevice *pdev)
>>
>> if (vdev->device_id != PCI_ANY_ID) {
>> if (vdev->device_id > 0xffff) {
>> - error_setg(&err, "invalid PCI device ID provided");
>> - ret = -EINVAL;
>> + error_setg(errp, "invalid PCI device ID provided");
>> goto error;
>> }
>> vfio_add_emulated_word(vdev, PCI_DEVICE_ID, vdev->device_id, ~0);
>> @@ -2635,8 +2629,7 @@ static int vfio_initfn(PCIDevice *pdev)
>>
>> if (vdev->sub_vendor_id != PCI_ANY_ID) {
>> if (vdev->sub_vendor_id > 0xffff) {
>> - error_setg(&err, "invalid PCI subsystem vendor ID provided");
>> - ret = -EINVAL;
>> + error_setg(errp, "invalid PCI subsystem vendor ID provided");
>> goto error;
>> }
>> vfio_add_emulated_word(vdev, PCI_SUBSYSTEM_VENDOR_ID,
>> @@ -2647,8 +2640,7 @@ static int vfio_initfn(PCIDevice *pdev)
>>
>> if (vdev->sub_device_id != PCI_ANY_ID) {
>> if (vdev->sub_device_id > 0xffff) {
>> - error_setg(&err, "invalid PCI subsystem device ID provided");
>> - ret = -EINVAL;
>> + error_setg(errp, "invalid PCI subsystem device ID provided");
>> goto error;
>> }
>> vfio_add_emulated_word(vdev, PCI_SUBSYSTEM_ID, vdev->sub_device_id,
>> ~0);
>> @@ -2702,10 +2694,9 @@ static int vfio_initfn(PCIDevice *pdev)
>> struct vfio_region_info *opregion;
>>
>> if (vdev->pdev.qdev.hotplugged) {
>> - error_setg(&err,
>> + error_setg(errp,
>> "cannot support IGD OpRegion feature on hotplugged "
>> "device");
>> - ret = -EINVAL;
>> goto out_teardown;
>> }
>>
>> @@ -2713,7 +2704,7 @@ 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_setg_errno(&err, -ret,
>> + error_setg_errno(errp, -ret,
>> "does not support requested IGD OpRegion
>> feature");
>> goto out_teardown;
>> }
>> @@ -2721,7 +2712,6 @@ static int vfio_initfn(PCIDevice *pdev)
>> vfio_pci_igd_opregion_init(vdev, opregion, &err);
>> g_free(opregion);
>> if (err) {
>> - ret = -EINVAL;
>> goto out_teardown;
>> }
>> }
>> @@ -2743,6 +2733,7 @@ static int vfio_initfn(PCIDevice *pdev)
>> pci_device_set_intx_routing_notifier(&vdev->pdev, vfio_intx_update);
>> ret = vfio_intx_enable(vdev, &err);
>> if (ret) {
>> + error_setg_errno(errp, -ret, "failed to enable intx");
>
> If vfio_intx_enable() sets an error on any failure (as it should), then
> the later error_propagate(errp, err) will simply free err. Adding the
> error_setg_errno() here overrides the specific error set by
> vfio_intx_enable() with a generic one. Looks wrong to me.
Yes this is definitively wrong!
>
> If it doesn't, then the error_propagate() will work around that
> misbehavior. You should fix vfio_intx_enable() then.
>
>> goto out_teardown;
>> }
>> }
>> @@ -2751,17 +2742,18 @@ static int vfio_initfn(PCIDevice *pdev)
>> vfio_register_req_notifier(vdev);
>> vfio_setup_resetfn_quirk(vdev);
>>
>> - return 0;
>> + return;
>>
>> 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);
>> + error_propagate(errp, err);
>> +
>> + if (*errp) {
>> + error_prepend(errp, ERR_PREFIX, vdev->vbasedev.name);
>> }
>
> Dereferencing errp is unclean, because callers may pass null to ignore
> errors. The qdev core doesn't. However, error_prepend() does the right
> thing when passed null, namely nothing. Simply call it unconditionally.
understood.
Thank you for your time!
Best Regards
Eric
>
>> - return ret;
>> }
>>
>> static void vfio_instance_finalize(Object *obj)
>> @@ -2890,7 +2882,7 @@ static void vfio_pci_dev_class_init(ObjectClass
>> *klass, void *data)
>> dc->vmsd = &vfio_pci_vmstate;
>> dc->desc = "VFIO-based PCI device assignment";
>> set_bit(DEVICE_CATEGORY_MISC, dc->categories);
>> - pdc->init = vfio_initfn;
>> + pdc->realize = vfio_realize;
>> pdc->exit = vfio_exitfn;
>> pdc->config_read = vfio_pci_read_config;
>> pdc->config_write = vfio_pci_write_config;
>> diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
>> index da13322..ef81609 100644
>> --- a/hw/vfio/trace-events
>> +++ b/hw/vfio/trace-events
>> @@ -36,7 +36,7 @@ vfio_pci_hot_reset_dep_devices(int domain, int bus, int
>> slot, int function, int
>> vfio_pci_hot_reset_result(const char *name, const char *result) "%s hot
>> reset: %s"
>> vfio_populate_device_config(const char *name, unsigned long size, unsigned
>> long offset, unsigned long flags) "Device %s config:\n size: 0x%lx, offset:
>> 0x%lx, flags: 0x%lx"
>> vfio_populate_device_get_irq_info_failure(void) "VFIO_DEVICE_GET_IRQ_INFO
>> failure: %m"
>> -vfio_initfn(const char *name, int group_id) " (%s) group %d"
>> +vfio_realize(const char *name, int group_id) " (%s) group %d"
>> vfio_add_ext_cap_dropped(const char *name, uint16_t cap, uint16_t offset)
>> "%s address@hidden"
>> vfio_pci_reset(const char *name) " (%s)"
>> vfio_pci_reset_flr(const char *name) "%s FLR/VFIO_DEVICE_RESET"
>
- [Qemu-devel] [PATCH v2 05/12] vfio/pci: Pass an error object to vfio_add_capabilities, (continued)
- [Qemu-devel] [PATCH v2 05/12] vfio/pci: Pass an error object to vfio_add_capabilities, Eric Auger, 2016/09/20
- [Qemu-devel] [PATCH v2 06/12] vfio/pci: Pass an error object to vfio_pci_igd_opregion_init, Eric Auger, 2016/09/20
- [Qemu-devel] [PATCH v2 07/12] vfio: Pass an error object to vfio_get_group, Eric Auger, 2016/09/20
- [Qemu-devel] [PATCH v2 08/12] vfio: Pass an error object to vfio_get_device, Eric Auger, 2016/09/20
- [Qemu-devel] [PATCH v2 09/12] vfio/pci: Conversion to realize, Eric Auger, 2016/09/20
- [Qemu-devel] [PATCH v2 10/12] vfio/pci: Remove vfio_msix_early_setup returned value, Eric Auger, 2016/09/20
- [Qemu-devel] [PATCH v2 11/12] vfio/pci: Remove vfio_populate_device returned value, Eric Auger, 2016/09/20
- [Qemu-devel] [PATCH v2 12/12] vfio/pci: Handle host oversight, Eric Auger, 2016/09/20
- Re: [Qemu-devel] [PATCH v2 00/12] Convert VFIO-PCI to realize, Markus Armbruster, 2016/09/22