backends/iommufd: Make iommufd_backend_*() return bool

This is to follow the coding standand to return bool if 'Error **'
is used to pass error.

The changed functions include:

iommufd_backend_conn

backends/iommufd: Make iommufd_backend_*() return bool

This is to follow the coding standand to return bool if 'Error **'
is used to pass error.

The changed functions include:

iommufd_backend_connect
iommufd_backend_alloc_ioas

By this chance, simplify the functions a bit by avoiding duplicate
recordings, e.g., log through either error interface or trace, not
both.

Suggested-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>

show more ...

error: Drop superfluous #include "qapi/qmp/qerror.h"

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240312141343.3168265-2-armbru@redhat.com>

backends/iommufd: Fix missing ERRP_GUARD() for error_prepend()

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

* = Why, when and how to use ERRP_GUARD() =
*
*

backends/iommufd: Fix missing ERRP_GUARD() for error_prepend()

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>

show more ...

backends/iommufd: Fix missing ERRP_GUARD() for error_prepend()

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

* = Why, when and how to use ERRP_GUARD() =
*
*

backends/iommufd: Fix missing ERRP_GUARD() for error_prepend()

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>

show more ...

backends/iommufd: Fix missing ERRP_GUARD() for error_prepend()

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

* = Why, when and how to use ERRP_GUARD() =
*
*

backends/iommufd: Fix missing ERRP_GUARD() for error_prepend()

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>

show more ...

backends/iommufd: Remove mutex

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

backends/iommufd: Remove mutex

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>

show more ...

backends/iommufd: Remove check on number of backend users

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

backends/iommufd: Remove check on number of backend users

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>

show more ...

backends/iommufd: Introduce the iommufd object

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 q

backends/iommufd: Introduce the iommufd object

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>

show more ...