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path: root/drivers/xen/xenbus
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2018-10-26xen: drop writing error messages to xenstoreJuergen Gross
xenbus_va_dev_error() will try to write error messages to Xenstore under the error/<dev-name>/error node (with <dev-name> something like "device/vbd/51872"). This will fail normally and another message about this failure is added to dmesg. I believe this is a remnant from very ancient times, as it was added in the first pvops rush of commits in 2007. So remove the additional message when writing to Xenstore failed as a minimum step. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracel.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2018-08-28xen: export device state to sysfsJoe Jin
Export device state to sysfs to allow for easier get device state. Signed-off-by: Joe Jin <joe.jin@oracle.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Juergen Gross <jgross@suse.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-05-17xen/store: do not store local values in xen_start_infoRoger Pau Monne
There's no need to store the xenstore page or event channel in xen_start_info if they are locally initialized. This also fixes PVH local xenstore initialization due to the lack of xen_start_info in that case. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2018-04-17xen: xenbus_dev_frontend: Really return response stringSimon Gaiser
xenbus_command_reply() did not actually copy the response string and leaked stack content instead. Fixes: 9a6161fe73bd ("xen: return xenstore command failures via response instead of rc") Signed-off-by: Simon Gaiser <simon@invisiblethingslab.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-03-21xen: xenbus_dev_frontend: Verify body of XS_TRANSACTION_ENDSimon Gaiser
By guaranteeing that the argument of XS_TRANSACTION_END is valid we can assume that the transaction has been closed when we get an XS_ERROR response from xenstore (Note that we already verify that it's a valid transaction id). Signed-off-by: Simon Gaiser <simon@invisiblethingslab.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-03-21xen: xenbus: Catch closing of non existent transactionsSimon Gaiser
Users of the xenbus functions should never close a non existent transaction (for example by trying to closing the same transaction twice) but better catch it in xs_request_exit() than to corrupt the reference counter. Signed-off-by: Simon Gaiser <simon@invisiblethingslab.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-03-21xen: xenbus_dev_frontend: Fix XS_TRANSACTION_END handlingSimon Gaiser
Commit fd8aa9095a95 ("xen: optimize xenbus driver for multiple concurrent xenstore accesses") made a subtle change to the semantic of xenbus_dev_request_and_reply() and xenbus_transaction_end(). Before on an error response to XS_TRANSACTION_END xenbus_dev_request_and_reply() would not decrement the active transaction counter. But xenbus_transaction_end() has always counted the transaction as finished regardless of the response. The new behavior is that xenbus_dev_request_and_reply() and xenbus_transaction_end() will always count the transaction as finished regardless the response code (handled in xs_request_exit()). But xenbus_dev_frontend tries to end a transaction on closing of the device if the XS_TRANSACTION_END failed before. Trying to close the transaction twice corrupts the reference count. So fix this by also considering a transaction closed if we have sent XS_TRANSACTION_END once regardless of the return code. Cc: <stable@vger.kernel.org> # 4.11 Fixes: fd8aa9095a95 ("xen: optimize xenbus driver for multiple concurrent xenstore accesses") Signed-off-by: Simon Gaiser <simon@invisiblethingslab.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-03-08xen: xenbus: use put_device() instead of kfree()Arvind Yadav
Never directly free @dev after calling device_register(), even if it returned an error! Always use put_device() to give up the reference initialized. Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2018-02-17xenbus: track caller request idJoao Martins
Commit fd8aa9095a95 ("xen: optimize xenbus driver for multiple concurrent xenstore accesses") optimized xenbus concurrent accesses but in doing so broke UABI of /dev/xen/xenbus. Through /dev/xen/xenbus applications are in charge of xenbus message exchange with the correct header and body. Now, after the mentioned commit the replies received by application will no longer have the header req_id echoed back as it was on request (see specification below for reference), because that particular field is being overwritten by kernel. struct xsd_sockmsg { uint32_t type; /* XS_??? */ uint32_t req_id;/* Request identifier, echoed in daemon's response. */ uint32_t tx_id; /* Transaction id (0 if not related to a transaction). */ uint32_t len; /* Length of data following this. */ /* Generally followed by nul-terminated string(s). */ }; Before there was only one request at a time so req_id could simply be forwarded back and forth. To allow simultaneous requests we need a different req_id for each message thus kernel keeps a monotonic increasing counter for this field and is written on every request irrespective of userspace value. Forwarding again the req_id on userspace requests is not a solution because we would open the possibility of userspace-generated req_id colliding with kernel ones. So this patch instead takes another route which is to artificially keep user req_id while keeping the xenbus logic as is. We do that by saving the original req_id before xs_send(), use the private kernel counter as req_id and then once reply comes and was validated, we restore back the original req_id. Cc: <stable@vger.kernel.org> # 4.11 Fixes: fd8aa9095a ("xen: optimize xenbus driver for multiple concurrent xenstore accesses") Reported-by: Bhavesh Davda <bhavesh.davda@oracle.com> Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2018-02-11vfs: do bulk POLL* -> EPOLL* replacementLinus Torvalds
This is the mindless scripted replacement of kernel use of POLL* variables as described by Al, done by this script: for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'` for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done done with de-mangling cleanups yet to come. NOTE! On almost all architectures, the EPOLL* constants have the same values as the POLL* constants do. But they keyword here is "almost". For various bad reasons they aren't the same, and epoll() doesn't actually work quite correctly in some cases due to this on Sparc et al. The next patch from Al will sort out the final differences, and we should be all done. Scripted-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-28the rest of drivers/*: annotate ->poll() instancesAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-11-16Merge tag 'for-linus-4.15-rc1-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen updates from Juergen Gross: "Xen features and fixes for v4.15-rc1 Apart from several small fixes it contains the following features: - a series by Joao Martins to add vdso support of the pv clock interface - a series by Juergen Gross to add support for Xen pv guests to be able to run on 5 level paging hosts - a series by Stefano Stabellini adding the Xen pvcalls frontend driver using a paravirtualized socket interface" * tag 'for-linus-4.15-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (34 commits) xen/pvcalls: fix potential endless loop in pvcalls-front.c xen/pvcalls: Add MODULE_LICENSE() MAINTAINERS: xen, kvm: track pvclock-abi.h changes x86/xen/time: setup vcpu 0 time info page x86/xen/time: set pvclock flags on xen_time_init() x86/pvclock: add setter for pvclock_pvti_cpu0_va ptp_kvm: probe for kvm guest availability xen/privcmd: remove unused variable pageidx xen: select grant interface version xen: update arch/x86/include/asm/xen/cpuid.h xen: add grant interface version dependent constants to gnttab_ops xen: limit grant v2 interface to the v1 functionality xen: re-introduce support for grant v2 interface xen: support priv-mapping in an HVM tools domain xen/pvcalls: remove redundant check for irq >= 0 xen/pvcalls: fix unsigned less than zero error check xen/time: Return -ENODEV from xen_get_wallclock() xen/pvcalls-front: mark expected switch fall-through xen: xenbus_probe_frontend: mark expected switch fall-throughs xen/time: do not decrease steal time after live migration on xen ...
2017-11-03xen: xenbus_probe_frontend: mark expected switch fall-throughsGustavo A. R. Silva
In preparation to enabling -Wimplicit-fallthrough, mark switch cases where we are expecting to fall through. Addresses-Coverity-ID: 146562 Addresses-Coverity-ID: 146563 Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-09-18xen: don't compile pv-specific parts if XEN_PV isn't configuredJuergen Gross
xenbus_client.c contains some functions specific for pv guests. Enclose them with #ifdef CONFIG_XEN_PV to avoid compiling them when they are not needed (e.g. on ARM). Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-08-11xen: avoid deadlock in xenbusJuergen Gross
When starting the xenwatch thread a theoretical deadlock situation is possible: xs_init() contains: task = kthread_run(xenwatch_thread, NULL, "xenwatch"); if (IS_ERR(task)) return PTR_ERR(task); xenwatch_pid = task->pid; And xenwatch_thread() does: mutex_lock(&xenwatch_mutex); ... event->handle->callback(); ... mutex_unlock(&xenwatch_mutex); The callback could call unregister_xenbus_watch() which does: ... if (current->pid != xenwatch_pid) mutex_lock(&xenwatch_mutex); ... In case a watch is firing before xenwatch_pid could be set and the callback of that watch unregisters a watch, then a self-deadlock would occur. Avoid this by setting xenwatch_pid in xenwatch_thread(). Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2017-06-25xen: avoid deadlock in xenbus driverJuergen Gross
There has been a report about a deadlock in the xenbus driver: [ 247.979498] ====================================================== [ 247.985688] WARNING: possible circular locking dependency detected [ 247.991882] 4.12.0-rc4-00022-gc4b25c0 #575 Not tainted [ 247.997040] ------------------------------------------------------ [ 248.003232] xenbus/91 is trying to acquire lock: [ 248.007875] (&u->msgbuffer_mutex){+.+.+.}, at: [<ffff00000863e904>] xenbus_dev_queue_reply+0x3c/0x230 [ 248.017163] [ 248.017163] but task is already holding lock: [ 248.023096] (xb_write_mutex){+.+...}, at: [<ffff00000863a940>] xenbus_thread+0x5f0/0x798 [ 248.031267] [ 248.031267] which lock already depends on the new lock. [ 248.031267] [ 248.039615] [ 248.039615] the existing dependency chain (in reverse order) is: [ 248.047176] [ 248.047176] -> #1 (xb_write_mutex){+.+...}: [ 248.052943] __lock_acquire+0x1728/0x1778 [ 248.057498] lock_acquire+0xc4/0x288 [ 248.061630] __mutex_lock+0x84/0x868 [ 248.065755] mutex_lock_nested+0x3c/0x50 [ 248.070227] xs_send+0x164/0x1f8 [ 248.074015] xenbus_dev_request_and_reply+0x6c/0x88 [ 248.079427] xenbus_file_write+0x260/0x420 [ 248.084073] __vfs_write+0x48/0x138 [ 248.088113] vfs_write+0xa8/0x1b8 [ 248.091983] SyS_write+0x54/0xb0 [ 248.095768] el0_svc_naked+0x24/0x28 [ 248.099897] [ 248.099897] -> #0 (&u->msgbuffer_mutex){+.+.+.}: [ 248.106088] print_circular_bug+0x80/0x2e0 [ 248.110730] __lock_acquire+0x1768/0x1778 [ 248.115288] lock_acquire+0xc4/0x288 [ 248.119417] __mutex_lock+0x84/0x868 [ 248.123545] mutex_lock_nested+0x3c/0x50 [ 248.128016] xenbus_dev_queue_reply+0x3c/0x230 [ 248.133005] xenbus_thread+0x788/0x798 [ 248.137306] kthread+0x110/0x140 [ 248.141087] ret_from_fork+0x10/0x40 It is rather easy to avoid by dropping xb_write_mutex before calling xenbus_dev_queue_reply(). Fixes: fd8aa9095a95c02dcc35540a263267c29b8fda9d ("xen: optimize xenbus driver for multiple concurrent xenstore accesses"). Cc: <stable@vger.kernel.org> # 4.11 Reported-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Juergen Gross <jgross@suse.com> Tested-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2017-04-04xenbus: remove transaction holder from list before freeingJan Beulich
After allocation the item is being placed on the list right away. Consequently it needs to be taken off the list before freeing in the case xenbus_dev_request_and_reply() failed, as in that case the callback (xenbus_dev_queue_reply()) is not being called (and if it was called, it should do both). Fixes: 5584ea250ae44f929feb4c7bd3877d1c5edbf813 Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-02-27xenbus: Remove duplicate inclusion of linux/init.hMasanari Iida
This patch remove duplicate inclusion of linux/init.h in xenbus_dev_frontend.c. Confirm successfully compile after remove the line. Signed-off-by: Masanari Iida <standby24x7@gmail.com> Reviewed-by: Juergen Gross <jgross@suse.com>
2017-02-09xen: optimize xenbus driver for multiple concurrent xenstore accessesJuergen Gross
Handling of multiple concurrent Xenstore accesses through xenbus driver either from the kernel or user land is rather lame today: xenbus is capable to have one access active only at one point of time. Rewrite xenbus to handle multiple requests concurrently by making use of the request id of the Xenstore protocol. This requires to: - Instead of blocking inside xb_read() when trying to read data from the xenstore ring buffer do so only in the main loop of xenbus_thread(). - Instead of doing writes to the xenstore ring buffer in the context of the caller just queue the request and do the write in the dedicated xenbus thread. - Instead of just forwarding the request id specified by the caller of xenbus to xenstore use a xenbus internal unique request id. This will allow multiple outstanding requests. - Modify the locking scheme in order to allow multiple requests being active in parallel. - Instead of waiting for the reply of a user's xenstore request after writing the request to the xenstore ring buffer return directly to the caller and do the waiting in the read path. Additionally signal handling was optimized by avoiding waking up the xenbus thread or sending an event to Xenstore in case the addressed entity is known to be running already. As a result communication with Xenstore is sped up by a factor of up to 5: depending on the request type (read or write) and the amount of data transferred the gain was at least 20% (small reads) and went up to a factor of 5 for large writes. In the end some more rough edges of xenbus have been smoothed: - Handling of memory shortage when reading from xenstore ring buffer in the xenbus driver was not optimal: it was busy looping and issuing a warning in each loop. - In case of xenstore not running in dom0 but in a stubdom we end up with two xenbus threads running as the initialization of xenbus in dom0 expecting a local xenstored will be redone later when connecting to the xenstore domain. Up to now this was no problem as locking would prevent the two xenbus threads interfering with each other, but this was just a waste of kernel resources. - An out of memory situation while writing to or reading from the xenstore ring buffer no longer will lead to a possible loss of synchronization with xenstore. - The user read and write part are now interruptible by signals. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-02-09xen: modify xenstore watch event interfaceJuergen Gross
Today a Xenstore watch event is delivered via a callback function declared as: void (*callback)(struct xenbus_watch *, const char **vec, unsigned int len); As all watch events only ever come with two parameters (path and token) changing the prototype to: void (*callback)(struct xenbus_watch *, const char *path, const char *token); is the natural thing to do. Apply this change and adapt all users. Cc: konrad.wilk@oracle.com Cc: roger.pau@citrix.com Cc: wei.liu2@citrix.com Cc: paul.durrant@citrix.com Cc: netdev@vger.kernel.org Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Paul Durrant <paul.durrant@citrix.com> Reviewed-by: Wei Liu <wei.liu2@citrix.com> Reviewed-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-02-09xen: clean up xenbus internal headersJuergen Gross
The xenbus driver has an awful mixture of internally and globally visible headers: some of the internally used only stuff is defined in the global header include/xen/xenbus.h while some stuff defined in internal headers is used by other drivers, too. Clean this up by moving the externally used symbols to include/xen/xenbus.h and the symbols used internally only to a new header drivers/xen/xenbus/xenbus.h replacing xenbus_comms.h and xenbus_probe.h Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-02-08xenbus: Neaten xenbus_va_dev_errorJoe Perches
This function error patch can be simplified, so do so. Remove fail: label and somewhat obfuscating, used once "error_path" function. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2016-12-23xen: remove stale xs_input_avail() from headerJuergen Gross
In drivers/xen/xenbus/xenbus_comms.h there is a stale declaration of xs_input_avail(). Remove it. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2016-12-23xen: return xenstore command failures via response instead of rcJuergen Gross
When the xenbus driver does some special handling for a Xenstore command any error condition related to the command should be returned via an error response instead of letting the related write operation fail. Otherwise the user land handler might take wrong decisions assuming the connection to Xenstore is broken. While at it try to return the same error values xenstored would return for those cases. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2016-12-23xen: xenbus driver must not accept invalid transaction idsJuergen Gross
When accessing Xenstore in a transaction the user is specifying a transaction id which he normally obtained from Xenstore when starting the transaction. Xenstore is validating a transaction id against all known transaction ids of the connection the request came in. As all requests of a domain not being the one where Xenstore lives share one connection, validation of transaction ids of different users of Xenstore in that domain should be done by the kernel of that domain being the multiplexer between the Xenstore users in that domain and Xenstore. In order to prohibit one Xenstore user "hijacking" a transaction from another user the xenbus driver has to verify a given transaction id against all known transaction ids of the user before forwarding it to Xenstore. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2016-12-12xenbus: fix deadlock on writes to /proc/xen/xenbusDavid Vrabel
/proc/xen/xenbus does not work correctly. A read blocked waiting for a xenstore message holds the mutex needed for atomic file position updates. This blocks any writes on the same file handle, which can deadlock if the write is needed to unblock the read. Clear FMODE_ATOMIC_POS when opening this device to always get character device like sematics. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2016-12-08xen: xenbus: set error code on failurePan Bian
Variable err is initialized with 0. As a result, the return value may be 0 even if get_zeroed_page() fails to allocate memory. This patch fixes the bug, initializing err with "-ENOMEM". Signed-off-by: Pan Bian <bianpan2016@163.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2016-11-17xenfs: Use proc_create_mount_point() to create /proc/xenSeth Forshee
Mounting proc in user namespace containers fails if the xenbus filesystem is mounted on /proc/xen because this directory fails the "permanently empty" test. proc_create_mount_point() exists specifically to create such mountpoints in proc but is currently proc-internal. Export this interface to modules, then use it in xenbus when creating /proc/xen. Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2016-11-07xen: make use of xenbus_read_unsigned() in xenbusJuergen Gross
Use xenbus_read_unsigned() instead of xenbus_scanf() when possible. This requires to change the type of the reads from int to unsigned, but these cases have been wrong before: negative values are not allowed for the modified cases. Signed-off-by: Juergen Gross <jgross@suse.com> Acked-by: David Vrabel <david.vrabel@citrix.com>
2016-11-07xen: introduce xenbus_read_unsigned()Juergen Gross
There are multiple instances of code reading an optional unsigned parameter from Xenstore via xenbus_scanf(). Instead of repeating the same code over and over add a service function doing the job. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com>
2016-10-24Merge tag 'for-linus-4.9-rc2-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen fixes from David Vrabel: - advertise control feature flags in xenstore - fix x86 build when XEN_PVHVM is disabled * tag 'for-linus-4.9-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xenbus: check return value of xenbus_scanf() xenbus: prefer list_for_each() x86: xen: move cpu_up functions out of ifdef xenbus: advertise control feature flags
2016-10-24xenbus: check return value of xenbus_scanf()Jan Beulich
Don't ignore errors here: Set backend state to unknown when unsuccessful. Signed-off-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2016-10-24xenbus: prefer list_for_each()Jan Beulich
This is more efficient than list_for_each_safe() when list modification is accompanied by breaking out of the loop. Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2016-08-24xenbus: don't look up transaction IDs for ordinary writesJan Beulich
This should really only be done for XS_TRANSACTION_END messages, or else at least some of the xenstore-* tools don't work anymore. Fixes: 0beef634b8 ("xenbus: don't BUG() on user mode induced condition") Reported-by: Richard Schütz <rschuetz@uni-koblenz.de> Cc: <stable@vger.kernel.org> Signed-off-by: Jan Beulich <jbeulich@suse.com> Tested-by: Richard Schütz <rschuetz@uni-koblenz.de> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2016-07-27Merge tag 'for-linus-4.8-rc0-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen updates from David Vrabel: "Features and fixes for 4.8-rc0: - ACPI support for guests on ARM platforms. - Generic steal time support for arm and x86. - Support cases where kernel cpu is not Xen VCPU number (e.g., if in-guest kexec is used). - Use the system workqueue instead of a custom workqueue in various places" * tag 'for-linus-4.8-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (47 commits) xen: add static initialization of steal_clock op to xen_time_ops xen/pvhvm: run xen_vcpu_setup() for the boot CPU xen/evtchn: use xen_vcpu_id mapping xen/events: fifo: use xen_vcpu_id mapping xen/events: use xen_vcpu_id mapping in events_base x86/xen: use xen_vcpu_id mapping when pointing vcpu_info to shared_info x86/xen: use xen_vcpu_id mapping for HYPERVISOR_vcpu_op xen: introduce xen_vcpu_id mapping x86/acpi: store ACPI ids from MADT for future usage x86/xen: update cpuid.h from Xen-4.7 xen/evtchn: add IOCTL_EVTCHN_RESTRICT xen-blkback: really don't leak mode property xen-blkback: constify instance of "struct attribute_group" xen-blkfront: prefer xenbus_scanf() over xenbus_gather() xen-blkback: prefer xenbus_scanf() over xenbus_gather() xen: support runqueue steal time on xen arm/xen: add support for vm_assist hypercall xen: update xen headers xen-pciback: drop superfluous variables xen-pciback: short-circuit read path used for merging write values ...
2016-07-08xenbus: simplify xenbus_dev_request_and_reply()Jan Beulich
No need to retain a local copy of the full request message, only the type is really needed. Signed-off-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2016-07-08xenbus: don't bail early from xenbus_dev_request_and_reply()Jan Beulich
xenbus_dev_request_and_reply() needs to track whether a transaction is open. For XS_TRANSACTION_START messages it calls transaction_start() and for XS_TRANSACTION_END messages it calls transaction_end(). If sending an XS_TRANSACTION_START message fails or responds with an an error, the transaction is not open and transaction_end() must be called. If sending an XS_TRANSACTION_END message fails, the transaction is still open, but if an error response is returned the transaction is closed. Commit 027bd7e89906 ("xen/xenbus: Avoid synchronous wait on XenBus stalling shutdown/restart") introduced a regression where failed XS_TRANSACTION_START messages were leaving the transaction open. This can cause problems with suspend (and migration) as all transactions must be closed before suspending. It appears that the problematic change was added accidentally, so just remove it. Signed-off-by: Jan Beulich <jbeulich@suse.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2016-07-07xenbus: don't BUG() on user mode induced conditionJan Beulich
Inability to locate a user mode specified transaction ID should not lead to a kernel crash. For other than XS_TRANSACTION_START also don't issue anything to xenbus if the specified ID doesn't match that of any active transaction. Signed-off-by: Jan Beulich <jbeulich@suse.com> Cc: <stable@vger.kernel.org> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2016-07-06xen: xenbus: Remove create_workqueueBhaktipriya Shridhar
System workqueues have been able to handle high level of concurrency for a long time now and there's no reason to use dedicated workqueues just to gain concurrency. Replace dedicated xenbus_frontend_wq with the use of system_wq. Unlike a dedicated per-cpu workqueue created with create_workqueue(), system_wq allows multiple work items to overlap executions even on the same CPU; however, a per-cpu workqueue doesn't have any CPU locality or global ordering guarantees unless the target CPU is explicitly specified and the increase of local concurrency shouldn't make any difference. In this case, there is only a single work item, increase of concurrency level by switching to system_wq should not make any difference. Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2016-03-22Merge tag 'for-linus-4.6-rc0-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen updates from David Vrabel: "Features and fixes for 4.6: - Make earlyprintk=xen work for HVM guests - Remove module support for things never built as modules" * tag 'for-linus-4.6-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: drivers/xen: make platform-pci.c explicitly non-modular drivers/xen: make sys-hypervisor.c explicitly non-modular drivers/xen: make xenbus_dev_[front/back]end explicitly non-modular drivers/xen: make [xen-]ballon explicitly non-modular xen: audit usages of module.h ; remove unnecessary instances xen/x86: Drop mode-selecting ifdefs in startup_xen() xen/x86: Zero out .bss for PV guests hvc_xen: make early_printk work with HVM guests hvc_xen: fix xenboot for DomUs hvc_xen: add earlycon support
2016-03-21drivers/xen: make xenbus_dev_[front/back]end explicitly non-modularPaul Gortmaker
The Makefile / Kconfig currently controlling compilation here is: obj-y += xenbus_dev_frontend.o [...] obj-$(CONFIG_XEN_BACKEND) += xenbus_dev_backend.o ...with: drivers/xen/Kconfig:config XEN_BACKEND drivers/xen/Kconfig: bool "Backend driver support" ...meaning that they currently are not being built as modules by anyone. Lets remove the modular code that is essentially orphaned, so that when reading the driver there is no doubt it is builtin-only. Since module_init translates to device_initcall in the non-modular case, the init ordering remains unchanged with this commit. We also delete the MODULE_LICENSE tag since all that information is already contained at the top of the file in the comments. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2016-03-21xen: audit usages of module.h ; remove unnecessary instancesPaul Gortmaker
Code that uses no modular facilities whatsoever should not be sourcing module.h at all, since that header drags in a bunch of other headers with it. Similarly, code that is not explicitly using modular facilities like module_init() but only is declaring module_param setup variables should be using moduleparam.h and not the larger module.h file for that. In making this change, we also uncover an implicit use of BUG() in inline fcns within arch/arm/include/asm/xen/hypercall.h so we explicitly source <linux/bug.h> for that file now. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2016-02-22Merge tag 'for-linus-4.5-rc5-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen bug fixes from David Vrabel: - Two scsiback fixes (resource leak and spurious warning). - Fix DMA mapping of compound pages on arm/arm64. - Fix some pciback regressions in MSI-X handling. - Fix a pcifront crash due to some uninitialize state. * tag 'for-linus-4.5-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/pcifront: Fix mysterious crashes when NUMA locality information was extracted. xen/pcifront: Report the errors better. xen/pciback: Save the number of MSI-X entries to be copied later. xen/pciback: Check PF instead of VF for PCI_COMMAND_MEMORY xen: fix potential integer overflow in queue_reply xen/arm: correctly handle DMA mapping of compound pages xen/scsiback: avoid warnings when adding multiple LUNs to a domain xen/scsiback: correct frontend counting
2016-02-15xen: fix potential integer overflow in queue_replyInsu Yun
When len is greater than UINT_MAX - sizeof(*rb), in next allocation, it can overflow integer range and allocates small size of heap. After that, memcpy will overflow the allocated heap. Therefore, it needs to check the size of given length. Signed-off-by: Insu Yun <wuninsu@gmail.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2016-01-12xenbus: use virt_xxx barriersMichael S. Tsirkin
drivers/xen/xenbus/xenbus_comms.c uses full memory barriers to communicate with the other side. For guests compiled with CONFIG_SMP, smp_wmb and smp_mb would be sufficient, so mb() and wmb() here are only needed if a non-SMP guest runs on an SMP host. Switch to virt_xxx barriers which serve this exact purpose. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: David Vrabel <david.vrabel@citrix.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2015-10-23xenbus: Support multiple grants ring with 64KBJulien Grall
The PV ring may use multiple grants and expect them to be mapped contiguously in the virtual memory. Although, the current code is relying on a Linux page will be mapped to a single grant. On build where Linux is using a different page size than the grant (i.e other than 4KB), the grant will always be mapped on the first 4KB of each Linux page which make the final ring not contiguous in the memory. This can be fixed by mapping multiple grant in a same Linux page. Signed-off-by: Julien Grall <julien.grall@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-10-23xen/xenbus: Rename *RING_PAGE* to *RING_GRANT*Julien Grall
Linux may use a different page size than the size of grant. So make clear that the order is actually in number of grant. Signed-off-by: Julien Grall <julien.grall@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-10-23xen/xenbus: Use Xen page definitionJulien Grall
All the ring (xenstore, and PV rings) are always based on the page granularity of Xen. Signed-off-by: Julien Grall <julien.grall@citrix.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-10-23xen/balloon: make alloc_xenballoon_pages() always allocate low pagesDavid Vrabel
All users of alloc_xenballoon_pages() wanted low memory pages, so remove the option for high memory. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>