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2024-03-12backends/iommufd: Fix missing ERRP_GUARD() for error_prepend()Zhao Liu
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]. The iommufd_backend_set_fd() passes @errp to error_prepend(), to avoid the above issue, add missing ERRP_GUARD() at the beginning of this function. [1]: Issue description in the commit message of commit ae7c80a7bd73 ("error: New macro ERRP_GUARD()"). Cc: Yi Liu <yi.l.liu@intel.com> Cc: Eric Auger <eric.auger@redhat.com> Cc: Zhenzhong Duan <zhenzhong.duan@intel.com> Signed-off-by: Zhao Liu <zhao1.liu@intel.com> Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Message-ID: <20240311033822.3142585-3-zhao1.liu@linux.intel.com> Signed-off-by: Thomas Huth <thuth@redhat.com>
2024-01-05backends/iommufd: Remove mutexCédric Le Goater
Coverity reports a concurrent data access violation because be->users is being accessed in iommufd_backend_can_be_deleted() without holding the mutex. However, these routines are called from the QEMU main thread when a device is created. In this case, the code paths should be protected by the BQL lock and it should be safe to drop the IOMMUFD backend mutex. Simply remove it. Fixes: CID 1531550 Fixes: CID 1531549 Reviewed-by: Eric Auger <eric.auger@redhat.com> Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com> Signed-off-by: Cédric Le Goater <clg@redhat.com>
2024-01-05backends/iommufd: Remove check on number of backend usersCédric Le Goater
QOM already has a ref count on objects and it will assert much earlier, when INT_MAX is reached. Reviewed-by: Eric Auger <eric.auger@redhat.com> Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com> Signed-off-by: Cédric Le Goater <clg@redhat.com>
2023-12-19backends/iommufd: Introduce the iommufd objectEric Auger
Introduce an iommufd object which allows the interaction with the host /dev/iommu device. The /dev/iommu can have been already pre-opened outside of qemu, in which case the fd can be passed directly along with the iommufd object: This allows the iommufd object to be shared accross several subsystems (VFIO, VDPA, ...). For example, libvirt would open the /dev/iommu once. If no fd is passed along with the iommufd object, the /dev/iommu is opened by the qemu code. Suggested-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Eric Auger <eric.auger@redhat.com> Signed-off-by: Yi Liu <yi.l.liu@intel.com> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com> Reviewed-by: Cédric Le Goater <clg@redhat.com> Tested-by: Eric Auger <eric.auger@redhat.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Cédric Le Goater <clg@redhat.com>