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hw/vfio/pci: Fix missing ERRP_GUARD() for error_prepend()

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As the comment in qapi/error, passing @errp to error_prepend() requires
ERRP_GUARD():

* = Why, when and how to use ERRP_GUARD() =
*
* Without ERRP_GUARD(), use of the @errp parameter is restricted:
...
* - It should not be passed to error_prepend(), error_vprepend() or
*   error_append_hint(), because that doesn't work with &error_fatal.
* ERRP_GUARD() lifts these restrictions.
*
* To use ERRP_GUARD(), add it right at the beginning of the function.
* @errp can then be used without worrying about the argument being
* NULL or &error_fatal.

ERRP_GUARD() could avoid the case when @errp is &error_fatal, the user
can't see this additional information, because exit() happens in
error_setg earlier than information is added [1].

In hw/vfio/pci.c, there are 2 functions passing @errp to error_prepend()
without ERRP_GUARD():
- vfio_add_std_cap()
- vfio_realize()

The @errp of vfio_add_std_cap() is also from vfio_realize(). And
vfio_realize(), as a PCIDeviceClass.realize method, its @errp is from
DeviceClass.realize so that there is no guarantee that the @errp won't
point to @error_fatal.

To avoid the issue like [1] said, add missing ERRP_GUARD() at their
beginning.

[1]: Issue description in the commit message of commit ae7c80a7bd
     ("error: New macro ERRP_GUARD()").

Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Message-ID: <20240311033822.3142585-24-zhao1.liu@linux.intel.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
This commit is contained in:
Zhao Liu 2024-03-11 11:38:16 +08:00 committed by Thomas Huth
parent 447655089e
commit cf8afdfad4
1 changed files with 2 additions and 0 deletions
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2
hw/vfio/pci.c
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@ -2136,6 +2136,7 @@ static void vfio_check_af_flr(VFIOPCIDevice *vdev, uint8_t pos)
static int vfio_add_std_cap(VFIOPCIDevice *vdev, uint8_t pos, Error **errp)
{
ERRP_GUARD();
PCIDevice *pdev = &vdev->pdev;
uint8_t cap_id, next, size;
int ret;
@ -2942,6 +2943,7 @@ static void vfio_unregister_req_notifier(VFIOPCIDevice *vdev)
static void vfio_realize(PCIDevice *pdev, Error **errp)
{
ERRP_GUARD();
VFIOPCIDevice *vdev = VFIO_PCI(pdev);
VFIODevice *vbasedev = &vdev->vbasedev;
char *tmp, *subsys;