linux/include/xen, branch v5.11

arm/xen: Don't probe xenbus as part of an early initcall

2021-02-11T06:49:37Z

After Commit 3499ba8198cad ("xen: Fix event channel callback via INTX/GSI"), xenbus_probe() will be called too early on Arm. This will recent to a guest hang during boot. If the hang wasn't there, we would have ended up to call xenbus_probe() twice (the second time is in xenbus_probe_initcall()). We don't need to initialize xenbus_probe() early for Arm guest. Therefore, the call in xen_guest_init() is now removed. After this change, there is no more external caller for xenbus_probe(). So the function is turned to a static one. Interestingly there were two prototypes for it. Cc: stable@vger.kernel.org Fixes: 3499ba8198cad ("xen: Fix event channel callback via INTX/GSI") Reported-by: Ian Jackson Signed-off-by: Julien Grall Reviewed-by: David Woodhouse Reviewed-by: Stefano Stabellini Link: https://lore.kernel.org/r/20210210170654.5377-1-julien@xen.org Signed-off-by: Juergen Gross

xen: Fix event channel callback via INTX/GSI

2021-01-13T15:12:00Z

For a while, event channel notification via the PCI platform device has been broken, because we attempt to communicate with xenstore before we even have notifications working, with the xs_reset_watches() call in xs_init(). We tend to get away with this on Xen versions below 4.0 because we avoid calling xs_reset_watches() anyway, because xenstore might not cope with reading a non-existent key. And newer Xen *does* have the vector callback support, so we rarely fall back to INTX/GSI delivery. To fix it, clean up a bit of the mess of xs_init() and xenbus_probe() startup. Call xs_init() directly from xenbus_init() only in the !XS_HVM case, deferring it to be called from xenbus_probe() in the XS_HVM case instead. Then fix up the invocation of xenbus_probe() to happen either from its device_initcall if the callback is available early enough, or when the callback is finally set up. This means that the hack of calling xenbus_probe() from a workqueue after the first interrupt, or directly from the PCI platform device setup, is no longer needed. Signed-off-by: David Woodhouse Reviewed-by: Boris Ostrovsky Link: https://lore.kernel.org/r/20210113132606.422794-2-dwmw2@infradead.org Signed-off-by: Juergen Gross

xen/xenbus: Count pending messages for each watch

2020-12-14T09:07:13Z

This commit adds a counter of pending messages for each watch in the struct. It is used to skip unnecessary pending messages lookup in 'unregister_xenbus_watch()'. It could also be used in 'will_handle' callback. This is part of XSA-349 Cc: stable@vger.kernel.org Signed-off-by: SeongJae Park Reported-by: Michael Kurth Reported-by: Pawel Wieczorkiewicz Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross

xen/xenbus: Add 'will_handle' callback support in xenbus_watch_path()

2020-12-14T09:04:18Z

Some code does not directly make 'xenbus_watch' object and call 'register_xenbus_watch()' but use 'xenbus_watch_path()' instead. This commit adds support of 'will_handle' callback in the 'xenbus_watch_path()' and it's wrapper, 'xenbus_watch_pathfmt()'. This is part of XSA-349 Cc: stable@vger.kernel.org Signed-off-by: SeongJae Park Reported-by: Michael Kurth Reported-by: Pawel Wieczorkiewicz Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross

xen/xenbus: Allow watches discard events before queueing

2020-12-14T09:02:45Z

If handling logics of watch events are slower than the events enqueue logic and the events can be created from the guests, the guests could trigger memory pressure by intensively inducing the events, because it will create a huge number of pending events that exhausting the memory. Fortunately, some watch events could be ignored, depending on its handler callback. For example, if the callback has interest in only one single path, the watch wouldn't want multiple pending events. Or, some watches could ignore events to same path. To let such watches to volutarily help avoiding the memory pressure situation, this commit introduces new watch callback, 'will_handle'. If it is not NULL, it will be called for each new event just before enqueuing it. Then, if the callback returns false, the event will be discarded. No watch is using the callback for now, though. This is part of XSA-349 Cc: stable@vger.kernel.org Signed-off-by: SeongJae Park Reported-by: Michael Kurth Reported-by: Pawel Wieczorkiewicz Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross

xen: don't use page->lru for ZONE_DEVICE memory

2020-12-09T09:31:41Z

Commit 9e2369c06c8a18 ("xen: add helpers to allocate unpopulated memory") introduced usage of ZONE_DEVICE memory for foreign memory mappings. Unfortunately this collides with using page->lru for Xen backend private page caches. Fix that by using page->zone_device_data instead. Cc: # 5.9 Fixes: 9e2369c06c8a18 ("xen: add helpers to allocate unpopulated memory") Signed-off-by: Juergen Gross Reviewed-by: Boris Ostrovsky Reviewed-by: Jason Andryuk Signed-off-by: Juergen Gross

xen: add helpers for caching grant mapping pages

2020-12-09T09:31:37Z

Instead of having similar helpers in multiple backend drivers use common helpers for caching pages allocated via gnttab_alloc_pages(). Make use of those helpers in blkback and scsiback. Cc: # 5.9 Signed-off-by: Juergen Gross Reviewed-by: Boris Ostrovsky Signed-off-by: Juergen Gross

Merge tag 'for-linus-5.10b-rc1c-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2020-10-25T17:55:35Z

Pull more xen updates from Juergen Gross: - a series for the Xen pv block drivers adding module parameters for better control of resource usge - a cleanup series for the Xen event driver * tag 'for-linus-5.10b-rc1c-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: Documentation: add xen.fifo_events kernel parameter description xen/events: unmask a fifo event channel only if it was masked xen/events: only register debug interrupt for 2-level events xen/events: make struct irq_info private to events_base.c xen: remove no longer used functions xen-blkfront: Apply changed parameter name to the document xen-blkfront: add a parameter for disabling of persistent grants xen-blkback: add a parameter for disabling of persistent grants

xen: remove no longer used functions

2020-10-23T10:41:25Z

With the switch to the lateeoi model for interdomain event channels some functions are no longer in use. Remove them. Suggested-by: Jan Beulich Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Link: https://lore.kernel.org/r/20201022094907.28560-2-jgross@suse.com Signed-off-by: Boris Ostrovsky

Merge tag 'for-linus-5.10b-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2020-10-20T16:24:01Z

Pull more xen updates from Juergen Gross: - A single patch to fix the Xen security issue XSA-331 (malicious guests can DoS dom0 by triggering NULL-pointer dereferences or access to stale data). - A larger series to fix the Xen security issue XSA-332 (malicious guests can DoS dom0 by sending events at high frequency leading to dom0's vcpus being busy in IRQ handling for elongated times). * tag 'for-linus-5.10b-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/events: block rogue events for some time xen/events: defer eoi in case of excessive number of events xen/events: use a common cpu hotplug hook for event channels xen/events: switch user event channels to lateeoi model xen/pciback: use lateeoi irq binding xen/pvcallsback: use lateeoi irq binding xen/scsiback: use lateeoi irq binding xen/netback: use lateeoi irq binding xen/blkback: use lateeoi irq binding xen/events: add a new "late EOI" evtchn framework xen/events: fix race in evtchn_fifo_unmask() xen/events: add a proper barrier to 2-level uevent unmasking xen/events: avoid removing an event channel while handling it