linux-dev/drivers/s390/cio/device_ops.c, branch linus/master

s390/cio: make ccw_device_dma_* more robust

2021-10-26T13:21:30Z

Since commit 48720ba56891 ("virtio/s390: use DMA memory for ccw I/O and classic notifiers") we were supposed to make sure that virtio_ccw_release_dev() completes before the ccw device and the attached dma pool are torn down, but unfortunately we did not. Before that commit it used to be OK to delay cleaning up the memory allocated by virtio-ccw indefinitely (which isn't really intuitive for guys used to destruction happens in reverse construction order), but now we trigger a BUG_ON if the genpool is destroyed before all memory allocated from it is deallocated. Which brings down the guest. We can observe this problem, when unregister_virtio_device() does not give up the last reference to the virtio_device (e.g. because a virtio-scsi attached scsi disk got removed without previously unmounting its previously mounted partition). To make sure that the genpool is only destroyed after all the necessary freeing is done let us take a reference on the ccw device on each ccw_device_dma_zalloc() and give it up on each ccw_device_dma_free(). Actually there are multiple approaches to fixing the problem at hand that can work. The upside of this one is that it is the safest one while remaining simple. We don't crash the guest even if the driver does not pair allocations and frees. The downside is the reference counting overhead, that the reference counting for ccw devices becomes more complex, in a sense that we need to pair the calls to the aforementioned functions for it to be correct, and that if we happen to leak, we leak more than necessary (the whole ccw device instead of just the genpool). Some alternatives to this approach are taking a reference in virtio_ccw_online() and giving it up in virtio_ccw_release_dev() or making sure virtio_ccw_release_dev() completes its work before virtio_ccw_remove() returns. The downside of these approaches is that these are less safe against programming errors. Cc: # v5.3 Signed-off-by: Halil Pasic Fixes: 48720ba56891 ("virtio/s390: use DMA memory for ccw I/O and classic notifiers") Reported-by: bfu@redhat.com Reviewed-by: Vineeth Vijayan Acked-by: Cornelia Huck Signed-off-by: Vasily Gorbik

s390/cio: Helper functions to read CSSID, IID, and CHID

2020-09-15T20:21:46Z

Add helper functions to expose Channel Subsystem ID (CSSID), MIF Image Id (IID), Channel ID (CHID) and Channel Path ID (CHPID). These values are required by the qeth driver's exploitation of network- address-change-notifications to determine which entries belong to this interface. Store the Partition identifier in System log, as this may be used to map a Linux view to a Hardware view for debugging purpose. Signed-off-by: Alexandra Winter Reviewed-by: Vineeth Vijayan Signed-off-by: Julian Wiedmann Acked-by: Heiko Carstens Signed-off-by: David S. Miller

s390/cio: Add new Operation Code OC3 to PNSO

2020-09-15T20:21:46Z

Add support for operation code 3 (OC3) of the Perform-Network-Subchannel-Operations (PNSO) function of the Channel-Subsystem-Call (CHSC) instruction. PNSO provides 2 operation codes: OC0 - BRIDGE_INFO OC3 - ADDR_INFO (new) Extend the function calls to *pnso* to pass the OC and add new response code 0108. Support for OC3 is indicated by a flag in the css_general_characteristics. Signed-off-by: Alexandra Winter Reviewed-by: Julian Wiedmann Reviewed-by: Peter Oberparleiter Reviewed-by: Vineeth Vijayan Signed-off-by: Julian Wiedmann Acked-by: Heiko Carstens Signed-off-by: David S. Miller

s390/cio, s390/qeth: cleanup PNSO CHSC

2020-05-28T10:21:55Z

CHSC3D (PNSO - perform network subchannel operation) is used for OC0 (Store-network-bridging-information) as well as for OC3 (Store-network-address-information). So common fields are renamed from *brinfo* to *pnso*. Also *_bridge_host_* is changed into *_addr_change_*, e.g. qeth_bridge_host_event to qeth_addr_change_event, for the same reasons. The keywords in the card traces are changed accordingly. Remove unused L3 types, as PNSO will only return Layer2 entries. Make PNSO CHSC implementation more consistent with existing API usage: Add new function ccw_device_pnso() to drivers/s390/cio/device_ops.c and the function declaration to arch/s390/include/asm/ccwdev.h, which takes a struct ccw_device * as parameter instead of schid and calls chsc_pnso(). PNSO CHSC has no strict relationship to qdio. So move the calling function from qdio to qeth_l2 and move the necessary structures to a new file arch/s390/include/asm/chsc.h. Do response code evaluation only in chsc_error_from_response() and use return code in all other places. qeth_anset_makerc() was meant to evaluate the PNSO response code, but never did, because pnso_rc was already non-zero. Indentation was corrected in some places. Signed-off-by: Alexandra Winter Reviewed-by: Peter Oberparleiter Reviewed-by: Vineeth Vijayan Reviewed-by: Julian Wiedmann Signed-off-by: Vasily Gorbik

s390/dasd/cio: Interpret ccw_device_get_mdc return value correctly

2019-12-20T18:52:01Z

The max data count (mdc) is an unsigned 16-bit integer value as per AR documentation and is received via ccw_device_get_mdc() for a specific path mask from the CIO layer. The function itself also always returns a positive mdc value or 0 in case mdc isn't supported or couldn't be determined. Though, the comment for this function describes a negative return value to indicate failures. As a result, the DASD device driver interprets the return value of ccw_device_get_mdc() incorrectly. The error case is essentially a dead code path. To fix this behaviour, check explicitly for a return value of 0 and change the comment for ccw_device_get_mdc() accordingly. This fix merely enables the error code path in the DASD functions get_fcx_max_data() and verify_fcx_max_data(). The actual functionality stays the same and is still correct. Reviewed-by: Cornelia Huck Signed-off-by: Jan Höppner Acked-by: Peter Oberparleiter Reviewed-by: Stefan Haberland Signed-off-by: Stefan Haberland Signed-off-by: Jens Axboe

s390/cio: fix intparm documentation

2019-09-19T10:56:06Z

The common I/O layer is maintaining an "intparm" inspired by the hardware intparm for driver usage. This "intparm" is not only applicaple for ssch, but also for hsch/csch. The kerneldoc states that it is only updated for hsch/csch if no prior request is pending; however, this is not what the code does (whether that would actually desireable is a different issue.) Let's at least fix the kerneldoc for now. Fixes: b2ffd8e9a76e ("[S390] cio: Add docbook comments.") Signed-off-by: Cornelia Huck Signed-off-by: Sebastian Ott Signed-off-by: Vasily Gorbik

s390/cio: add basic protected virtualization support

2019-06-15T10:25:00Z

As virtio-ccw devices are channel devices, we need to use the dma area within the common I/O layer for any communication with the hypervisor. Note that we do not need to use that area for control blocks directly referenced by instructions, e.g. the orb. It handles neither QDIO in the common code, nor any device type specific stuff (like channel programs constructed by the DASD driver). An interesting side effect is that virtio structures are now going to get allocated in 31 bit addressable storage. Signed-off-by: Halil Pasic Reviewed-by: Sebastian Ott Reviewed-by: Cornelia Huck Reviewed-by: Michael Mueller Tested-by: Michael Mueller Signed-off-by: Heiko Carstens

s390/cio: add helper to query utility strings per given ccw device

2018-05-23T06:06:56Z

Signed-off-by: Sebastian Ott Signed-off-by: Martin Schwidefsky

s390/cio: rename struct channel_path_desc

2018-03-26T14:13:11Z

Rename struct channel_path_desc to struct channel_path_desc_fmt0 to fit the scheme. Provide a macro for the function wrappers that gather this and related data from firmware. Signed-off-by: Sebastian Ott Reviewed-by: Peter Oberparleiter Signed-off-by: Martin Schwidefsky

s390/cio: fix ccw_device_start_timeout API

2018-02-22T09:09:22Z

There are cases a device driver can't start IO because the device is currently in use by cio. In this case the device driver is notified when the device is usable again. Using ccw_device_start_timeout we would set the timeout (and change an existing timeout) before we test for internal usage. Worst case this could lead to an unexpected timer deletion. Fix this by setting the timeout after we test for internal usage. Signed-off-by: Sebastian Ott Signed-off-by: Martin Schwidefsky