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2014-12-04xen/pciback: Don't deadlock when unbinding.Konrad Rzeszutek Wilk1-3/+11
As commit 0a9fd0152929db372ff61b0d6c280fdd34ae8bdb 'xen/pciback: Document the entry points for 'pcistub_put_pci_dev'' explained there are four entry points in this function. Two of them are when the user fiddles in the SysFS to unbind a device which might be in use by a guest or not. Both 'unbind' states will cause a deadlock as the the PCI lock has already been taken, which then pci_device_reset tries to take. We can simplify this by requiring that all callers of pcistub_put_pci_dev MUST hold the device lock. And then we can just call the lockless version of pci_device_reset. To make it even simpler we will modify xen_pcibk_release_pci_dev to quality whether it should take a lock or not - as it ends up calling xen_pcibk_release_pci_dev and needs to hold the lock. Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2011-09-21xen/pciback: miscellaneous adjustmentsJan Beulich1-1/+1
This is a minor bugfix and a set of small cleanups; as it is not clear whether this needs splitting into pieces (and if so, at what granularity), it is a single combined patch. - add a missing return statement to an error path in kill_domain_by_device() - use pci_is_enabled() rather than raw atomic_read() - remove a bogus attempt to zero-terminate an already zero-terminated string - #define DRV_NAME once uniformly in the shared local header - make DRIVER_ATTR() variables static - eliminate a pointless use of list_for_each_entry_safe() - add MODULE_ALIAS() - a little bit of constification - adjust a few messages - remove stray semicolons from inline function definitions Signed-off-by: Jan Beulich <jbeulich@suse.com> [v1: Dropped the resource_size fix, altered the description] [v2: Fixed cleanpatch.pl comments] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-09-21xen/pciback: use mutex rather than spinlock in passthrough backendJan Beulich1-19/+13
To accommodate the call to the callback function from __xen_pcibk_publish_pci_roots(), which so far dropped and the re- acquired the lock without checking that the list didn't actually change, convert the code to use a mutex instead (observing that the code taking the lock won't ever get called from non-sleepable context). As a result, drop the bogus use of list_for_each_entry_safe() and remove the inappropriate dropping of the lock. Signed-off-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-07-19xen/pciback: Have 'passthrough' option instead of XEN_PCIDEV_BACKEND_PASS and XEN_PCIDEV_BACKEND_VPCIKonrad Rzeszutek Wilk1-15/+28
.. compile options. This way the user can decide during runtime whether they want the default 'vpci' (virtual pci passthrough) or where the PCI devices are passed in without any BDF renumbering. The option 'passthrough' allows the user to toggle the it from 0 (vpci) to 1 (passthrough). Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-07-19xen/pciback: Drop two backends, squash and cleanup some code.Konrad Rzeszutek Wilk1-15/+15
- Remove the slot and controller controller backend as they are not used. - Document the find pciback_[read|write]_config_[byte|word|dword] to make it easier to find. - Collapse the code from conf_space_capability_msi into pciback_ops.c - Collapse conf_space_capability_[pm|vpd].c in conf_space_capability.c [and remove the conf_space_capability.h file] - Rename all visible functions from pciback to xen_pcibk. - Rename all the printk/pr_info, etc that use the "pciback" to say "xen-pciback". - Convert functions that are not referenced outside the code to be static to save on name space. - Do the same thing for structures that are internal to the driver. - Run checkpatch.pl after the renames and fixup its warnings and fix any compile errors caused by the variable rename - Cleanup any structs that checkpath.pl commented about or just look odd. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-07-19xen/pciback: Fine-grain the spinlocks and fix BUG: scheduling while atomic cases.Konrad Rzeszutek Wilk1-3/+6
We were using coarse spinlocks that could end up with a deadlock. This patch fixes that and makes the spinlocks much more fine-grained. We also drop be->watchding state spinlocks as they are already guarded by the xenwatch_thread against multiple customers. Without that we would trigger the BUG: scheduling while atomic. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-07-19xen/pciback: xen pci backend driver.Konrad Rzeszutek Wilk1-0/+178
This is the host side counterpart to the frontend driver in drivers/pci/xen-pcifront.c. The PV protocol is also implemented by frontend drivers in other OSes too, such as the BSDs. The PV protocol is rather simple. There is page shared with the guest, which has the 'struct xen_pci_sharedinfo' embossed in it. The backend has a thread that is kicked every-time the structure is changed and based on the operation field it performs specific tasks: XEN_PCI_OP_conf_[read|write]: Read/Write 0xCF8/0xCFC filtered data. (conf_space*.c) Based on which field is probed, we either enable/disable the PCI device, change power state, read VPD, etc. The major goal of this call is to provide a Physical IRQ (PIRQ) to the guest. The PIRQ is Xen hypervisor global IRQ value irrespective of the IRQ is tied in to the IO-APIC, or is a vector. For GSI type interrupts, the PIRQ==GSI holds. For MSI/MSI-X the PIRQ value != Linux IRQ number (thought PIRQ==vector). Please note, that with Xen, all interrupts (except those level shared ones) are injected directly to the guest - there is no host interaction. XEN_PCI_OP_[enable|disable]_msi[|x] (pciback_ops.c) Enables/disables the MSI/MSI-X capability of the device. These operations setup the MSI/MSI-X vectors for the guest and pass them to the frontend. When the device is activated, the interrupts are directly injected in the guest without involving the host. XEN_PCI_OP_aer_[detected|resume|mmio|slotreset]: In case of failure, perform the appropriate AER commands on the guest. Right now that is a cop-out - we just kill the guest. Besides implementing those commands, it can also - hide a PCI device from the host. When booting up, the user can specify xen-pciback.hide=(1:0:0)(BDF..) so that host does not try to use the device. The driver was lifted from linux-2.6.18.hg tree and fixed up so that it could compile under v3.0. Per suggestion from Jesse Barnes moved the driver to drivers/xen/xen-pciback. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>