commit 0991028cd49567d7016d1b224fe0117c35059f86 upstream.
Prior to this commit, if a grant mapping operation failed partially,
some of the entries in the map_ops array would be invalid, whereas all
of the entries in the kmap_ops array would be valid. This in turn would
cause the following logic in gntdev_map_grant_pages to become invalid:
for (i = 0; i < map->count; i++) {
if (map->map_ops[i].status == GNTST_okay) {
map->unmap_ops[i].handle = map->map_ops[i].handle;
if (!use_ptemod)
alloced++;
}
if (use_ptemod) {
if (map->kmap_ops[i].status == GNTST_okay) {
if (map->map_ops[i].status == GNTST_okay)
alloced++;
map->kunmap_ops[i].handle = map->kmap_ops[i].handle;
}
}
}
...
atomic_add(alloced, &map->live_grants);
Assume that use_ptemod is true (i.e., the domain mapping the granted
pages is a paravirtualized domain). In the code excerpt above, note that
the "alloced" variable is only incremented when both kmap_ops[i].status
and map_ops[i].status are set to GNTST_okay (i.e., both mapping
operations are successful). However, as also noted above, there are
cases where a grant mapping operation fails partially, breaking the
assumption of the code excerpt above.
The aforementioned causes map->live_grants to be incorrectly set. In
some cases, all of the map_ops mappings fail, but all of the kmap_ops
mappings succeed, meaning that live_grants may remain zero. This in turn
makes it impossible to unmap the successfully grant-mapped pages pointed
to by kmap_ops, because unmap_grant_pages has the following snippet of
code at its beginning:
if (atomic_read(&map->live_grants) == 0)
return; /* Nothing to do */
In other cases where only some of the map_ops mappings fail but all
kmap_ops mappings succeed, live_grants is made positive, but when the
user requests unmapping the grant-mapped pages, __unmap_grant_pages_done
will then make map->live_grants negative, because the latter function
does not check if all of the pages that were requested to be unmapped
were actually unmapped, and the same function unconditionally subtracts
"data->count" (i.e., a value that can be greater than map->live_grants)
from map->live_grants. The side effects of a negative live_grants value
have not been studied.
The net effect of all of this is that grant references are leaked in one
of the above conditions. In Qubes OS v4.1 (which uses Xen's grant
mechanism extensively for X11 GUI isolation), this issue manifests
itself with warning messages like the following to be printed out by the
Linux kernel in the VM that had granted pages (that contain X11 GUI
window data) to dom0: "g.e. 0x1234 still pending", especially after the
user rapidly resizes GUI VM windows (causing some grant-mapping
operations to partially or completely fail, due to the fact that the VM
unshares some of the pages as part of the window resizing, making the
pages impossible to grant-map from dom0).
The fix for this issue involves counting all successful map_ops and
kmap_ops mappings separately, and then adding the sum to live_grants.
During unmapping, only the number of successfully unmapped grants is
subtracted from live_grants. The code is also modified to check for
negative live_grants values after the subtraction and warn the user.
Link: https://github.com/QubesOS/qubes-issues/issues/7631
Fixes: dbe97cff7dd9 ("xen/gntdev: Avoid blocking in unmap_grant_pages()")
Cc: stable@vger.kernel.org
Signed-off-by: M. Vefa Bicakci <m.v.b@runbox.com>
Acked-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20221002222006.2077-2-m.v.b@runbox.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f28347cc66395e96712f5c2db0a302ee75bafce6 upstream.
While working on XSA-361 and its follow-ups, I failed to spot another
place where the kernel mapping part of an operation was not treated the
same as the user space part. Detect and propagate errors and add a 2nd
pr_debug().
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/c2513395-74dc-aea3-9192-fd265aa44e35@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Co-authored-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 32ad11127b95236dfc52375f3707853194a7f4b4 upstream.
This code tries to store -EFAULT in an unsigned int. The
xenbus_file_read() function returns type ssize_t so the negative value
is returned as a positive value to the user.
This change forces another change to the min() macro. Originally, the
min() macro used "unsigned" type which checkpatch complains about. Also
unsigned type would break if "len" were not capped at MAX_RW_COUNT. Use
size_t for the min(). (No effect on runtime for the min_t() change).
Fixes: 2fb3683e7b ("xen: Add xenbus device driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Link: https://lore.kernel.org/r/YutxJUaUYRG/VLVc@kili
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 166d3863231667c4f64dee72b77d1102cdfad11f upstream.
The error paths of gntdev_mmap() can call unmap_grant_pages() even
though not all of the pages have been successfully mapped. This will
trigger the WARN_ON()s in __unmap_grant_pages_done(). The number of
warnings can be very large; I have observed thousands of lines of
warnings in the systemd journal.
Avoid this problem by only warning on unmapping failure if the handle
being unmapped is not INVALID_GRANT_HANDLE. The handle field of any
page that was not successfully mapped will be INVALID_GRANT_HANDLE, so
this catches all cases where unmapping can legitimately fail.
Fixes: dbe97cff7dd9 ("xen/gntdev: Avoid blocking in unmap_grant_pages()")
Cc: stable@vger.kernel.org
Suggested-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220710230522.1563-1-demi@invisiblethingslab.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit dbe97cff7dd9f0f75c524afdd55ad46be3d15295 upstream.
unmap_grant_pages() currently waits for the pages to no longer be used.
In https://github.com/QubesOS/qubes-issues/issues/7481, this lead to a
deadlock against i915: i915 was waiting for gntdev's MMU notifier to
finish, while gntdev was waiting for i915 to free its pages. I also
believe this is responsible for various deadlocks I have experienced in
the past.
Avoid these problems by making unmap_grant_pages async. This requires
making it return void, as any errors will not be available when the
function returns. Fortunately, the only use of the return value is a
WARN_ON(), which can be replaced by a WARN_ON when the error is
detected. Additionally, a failed call will not prevent further calls
from being made, but this is harmless.
Because unmap_grant_pages is now async, the grant handle will be sent to
INVALID_GRANT_HANDLE too late to prevent multiple unmaps of the same
handle. Instead, a separate bool array is allocated for this purpose.
This wastes memory, but stuffing this information in padding bytes is
too fragile. Furthermore, it is necessary to grab a reference to the
map before making the asynchronous call, and release the reference when
the call returns.
It is also necessary to guard against reentrancy in gntdev_map_put(),
and to handle the case where userspace tries to map a mapping whose
contents have not all been freed yet.
Fixes: 745282256c ("xen/gntdev: safely unmap grants in case they are still in use")
Cc: stable@vger.kernel.org
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220622022726.2538-1-demi@invisiblethingslab.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit dbac14a5a05ff8e1ce7c0da0e1f520ce39ec62ea upstream.
EXPORT_SYMBOL and __init is a bad combination because the .init.text
section is freed up after the initialization. Hence, modules cannot
use symbols annotated __init. The access to a freed symbol may end up
with kernel panic.
modpost used to detect it, but it has been broken for a decade.
Recently, I fixed modpost so it started to warn it again, then this
showed up in linux-next builds.
There are two ways to fix it:
- Remove __init
- Remove EXPORT_SYMBOL
I chose the latter for this case because none of the in-tree call-sites
(arch/arm/xen/enlighten.c, arch/x86/xen/grant-table.c) is compiled as
modular.
Fixes: 243848fc01 ("xen/grant-table: Move xlated_setup_gnttab_pages to common place")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20220606045920.4161881-1-masahiroy@kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 42baefac638f06314298087394b982ead9ec444b upstream.
gnttab_end_foreign_access() is used to free a grant reference and
optionally to free the associated page. In case the grant is still in
use by the other side processing is being deferred. This leads to a
problem in case no page to be freed is specified by the caller: the
caller doesn't know that the page is still mapped by the other side
and thus should not be used for other purposes.
The correct way to handle this situation is to take an additional
reference to the granted page in case handling is being deferred and
to drop that reference when the grant reference could be freed
finally.
This requires that there are no users of gnttab_end_foreign_access()
left directly repurposing the granted page after the call, as this
might result in clobbered data or information leaks via the not yet
freed grant reference.
This is part of CVE-2022-23041 / XSA-396.
Reported-by: Simon Gaiser <simon@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit b0576cc9c6b843d99c6982888d59a56209341888 upstream.
Instead of __get_free_pages() and free_pages() use alloc_pages_exact()
and free_pages_exact(). This is in preparation of a change of
gnttab_end_foreign_access() which will prohibit use of high-order
pages.
This is part of CVE-2022-23041 / XSA-396.
Reported-by: Simon Gaiser <simon@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 1dbd11ca75fe664d3e54607547771d021f531f59 upstream.
Remove gnttab_query_foreign_access(), as it is unused and unsafe to
use.
All previous use cases assumed a grant would not be in use after
gnttab_query_foreign_access() returned 0. This information is useless
in best case, as it only refers to a situation in the past, which could
have changed already.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit d3b6372c5881cb54925212abb62c521df8ba4809 upstream.
Using gnttab_query_foreign_access() is unsafe, as it is racy by design.
The use case in the gntalloc driver is not needed at all. While at it
replace the call of gnttab_end_foreign_access_ref() with a call of
gnttab_end_foreign_access(), which is what is really wanted there. In
case the grant wasn't used due to an allocation failure, just free the
grant via gnttab_free_grant_reference().
This is CVE-2022-23039 / part of XSA-396.
Reported-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 6b1775f26a2da2b05a6dc8ec2b5d14e9a4701a1a upstream.
Add a new grant table function gnttab_try_end_foreign_access(), which
will remove and free a grant if it is not in use.
Its main use case is to either free a grant if it is no longer in use,
or to take some other action if it is still in use. This other action
can be an error exit, or (e.g. in the case of blkfront persistent grant
feature) some special handling.
This is CVE-2022-23036, CVE-2022-23038 / part of XSA-396.
Reported-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 3777ea7bac3113005b7180e6b9dadf16d19a5827 upstream.
Letting xenbus_grant_ring() tear down grants in the error case is
problematic, as the other side could already have used these grants.
Calling gnttab_end_foreign_access_ref() without checking success is
resulting in an unclear situation for any caller of xenbus_grant_ring()
as in the error case the memory pages of the ring page might be
partially mapped. Freeing them would risk unwanted foreign access to
them, while not freeing them would leak memory.
In order to remove the need to undo any gnttab_grant_foreign_access()
calls, use gnttab_alloc_grant_references() to make sure no further
error can occur in the loop granting access to the ring pages.
It should be noted that this way of handling removes leaking of
grant entries in the error case, too.
This is CVE-2022-23040 / part of XSA-396.
Reported-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 36e8f60f0867d3b70d398d653c17108459a04efe upstream.
If the xenstore page hasn't been allocated properly, reading the value
of the related hvm_param (HVM_PARAM_STORE_PFN) won't actually return
error. Instead, it will succeed and return zero. Instead of attempting
to xen_remap a bad guest physical address, detect this condition and
return early.
Note that although a guest physical address of zero for
HVM_PARAM_STORE_PFN is theoretically possible, it is not a good choice
and zero has never been validly used in that capacity.
Also recognize all bits set as an invalid value.
For 32-bit Linux, any pfn above ULONG_MAX would get truncated. Pfns
above ULONG_MAX should never be passed by the Xen tools to HVM guests
anyway, so check for this condition and return early.
Cc: stable@vger.kernel.org
Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Link: https://lore.kernel.org/r/20211123210748.1910236-1-sstabellini@kernel.org
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 08f6c2b09ebd4b326dbe96d13f94fee8f9814c78 upstream.
In case of errors in xenbus_init (e.g. missing xen_store_gfn parameter),
we goto out_error but we forget to reset xen_store_domain_type to
XS_UNKNOWN. As a consequence xenbus_probe_initcall and other initcalls
will still try to initialize xenstore resulting into a crash at boot.
[ 2.479830] Call trace:
[ 2.482314] xb_init_comms+0x18/0x150
[ 2.486354] xs_init+0x34/0x138
[ 2.489786] xenbus_probe+0x4c/0x70
[ 2.498432] xenbus_probe_initcall+0x2c/0x7c
[ 2.503944] do_one_initcall+0x54/0x1b8
[ 2.507358] kernel_init_freeable+0x1ac/0x210
[ 2.511617] kernel_init+0x28/0x130
[ 2.516112] ret_from_fork+0x10/0x20
Cc: <Stable@vger.kernel.org>
Cc: jbeulich@suse.com
Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Link: https://lore.kernel.org/r/20211115222719.2558207-1-sstabellini@kernel.org
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 4745ea2628bb43a7ec34b71763b5a56407b33990 ]
Return NULL instead of passing to ERR_PTR while err is zero,
this fix smatch warnings:
drivers/xen/xen-pciback/conf_space_capability.c:163
pm_ctrl_init() warn: passing zero to 'ERR_PTR'
Fixes: a92336a117 ("xen/pciback: Drop two backends, squash and cleanup some code.")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20211008074417.8260-1-yuehaibing@huawei.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 40fdea0284bb20814399da0484a658a96c735d90 upstream.
When running as PVH or HVM guest with actual memory < max memory the
hypervisor is using "populate on demand" in order to allow the guest
to balloon down from its maximum memory size. For this to work
correctly the guest must not touch more memory pages than its target
memory size as otherwise the PoD cache will be exhausted and the guest
is crashed as a result of that.
In extreme cases ballooning down might not be finished today before
the init process is started, which can consume lots of memory.
In order to avoid random boot crashes in such cases, add a late init
call to wait for ballooning down having finished for PVH/HVM guests.
Warn on console if initial ballooning fails, panic() after stalling
for more than 3 minutes per default. Add a module parameter for
changing this timeout.
[boris: replaced pr_info() with pr_notice()]
Cc: <stable@vger.kernel.org>
Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20211102091944.17487-1-jgross@suse.com
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 319933a80fd4f07122466a77f93e5019d71be74c upstream.
In case a ballooning action is cancelled the new kernel thread handling
the ballooning might end up in a busy loop.
Fix that by handling the cancelled action gracefully.
While at it introduce a short wait for the BP_WAIT case.
Cc: stable@vger.kernel.org
Fixes: 8480ed9c2bbd56 ("xen/balloon: use a kernel thread instead a workqueue")
Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: Jason Andryuk <jandryuk@gmail.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20211005133433.32008-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e11423d6721dd63b23fb41ade5e8d0b448b17780 upstream.
xen_pfn_t is the same size as int only on 32-bit builds (and not even
on Arm32). Hence pfns[] can't be used directly to read individual error
values returned from xen_remap_domain_mfn_array(); every other error
indicator would be skipped/ignored on 64-bit.
Fixes: 3ad0876554 ("xen/privcmd: add IOCTL_PRIVCMD_MMAP_RESOURCE")
Cc: stable@vger.kernel.org
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/aa6d6a67-6889-338a-a910-51e889f792d5@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
commit 96f5bd03e1be606987644b71899ea56a8d05f825 upstream.
Commit 8480ed9c2bbd56 ("xen/balloon: use a kernel thread instead a
workqueue") switched the Xen balloon driver to use a kernel thread.
Unfortunately the patch omitted to call try_to_freeze() or to use
wait_event_freezable_timeout(), causing a system suspend to fail.
Fixes: 8480ed9c2bbd56 ("xen/balloon: use a kernel thread instead a workqueue")
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20210920100345.21939-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 8480ed9c2bbd56fc86524998e5f2e3e22f5038f6 ]
Today the Xen ballooning is done via delayed work in a workqueue. This
might result in workqueue hangups being reported in case of large
amounts of memory are being ballooned in one go (here 16GB):
BUG: workqueue lockup - pool cpus=6 node=0 flags=0x0 nice=0 stuck for 64s!
Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 12: cpus=6 node=0 flags=0x0 nice=0 active=2/256 refcnt=3
in-flight: 229:balloon_process
pending: cache_reap
workqueue events_freezable_power_: flags=0x84
pwq 12: cpus=6 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: disk_events_workfn
workqueue mm_percpu_wq: flags=0x8
pwq 12: cpus=6 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_update
pool 12: cpus=6 node=0 flags=0x0 nice=0 hung=64s workers=3 idle: 2222 43
This can easily be avoided by using a dedicated kernel thread for doing
the ballooning work.
Reported-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20210827123206.15429-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 88ca2521bd5b4e8b83743c01a2d4cb09325b51e9 ]
There is a TOCTOU issue in set_evtchn_to_irq. Rows in the evtchn_to_irq
mapping are lazily allocated in this function. The check whether the row
is already present and the row initialization is not synchronized. Two
threads can at the same time allocate a new row for evtchn_to_irq and
add the irq mapping to the their newly allocated row. One thread will
overwrite what the other has set for evtchn_to_irq[row] and therefore
the irq mapping is lost. This will trigger a BUG_ON later in
bind_evtchn_to_cpu:
INFO: pci 0000:1a:15.4: [1d0f:8061] type 00 class 0x010802
INFO: nvme 0000:1a:12.1: enabling device (0000 -> 0002)
INFO: nvme nvme77: 1/0/0 default/read/poll queues
CRIT: kernel BUG at drivers/xen/events/events_base.c:427!
WARN: invalid opcode: 0000 [#1] SMP NOPTI
WARN: Workqueue: nvme-reset-wq nvme_reset_work [nvme]
WARN: RIP: e030:bind_evtchn_to_cpu+0xc2/0xd0
WARN: Call Trace:
WARN: set_affinity_irq+0x121/0x150
WARN: irq_do_set_affinity+0x37/0xe0
WARN: irq_setup_affinity+0xf6/0x170
WARN: irq_startup+0x64/0xe0
WARN: __setup_irq+0x69e/0x740
WARN: ? request_threaded_irq+0xad/0x160
WARN: request_threaded_irq+0xf5/0x160
WARN: ? nvme_timeout+0x2f0/0x2f0 [nvme]
WARN: pci_request_irq+0xa9/0xf0
WARN: ? pci_alloc_irq_vectors_affinity+0xbb/0x130
WARN: queue_request_irq+0x4c/0x70 [nvme]
WARN: nvme_reset_work+0x82d/0x1550 [nvme]
WARN: ? check_preempt_wakeup+0x14f/0x230
WARN: ? check_preempt_curr+0x29/0x80
WARN: ? nvme_irq_check+0x30/0x30 [nvme]
WARN: process_one_work+0x18e/0x3c0
WARN: worker_thread+0x30/0x3a0
WARN: ? process_one_work+0x3c0/0x3c0
WARN: kthread+0x113/0x130
WARN: ? kthread_park+0x90/0x90
WARN: ret_from_fork+0x3a/0x50
This patch sets evtchn_to_irq rows via a cmpxchg operation so that they
will be set only once. The row is now cleared before writing it to
evtchn_to_irq in order to not create a race once the row is visible for
other threads.
While at it, do not require the page to be zeroed, because it will be
overwritten with -1's in clear_evtchn_to_irq_row anyway.
Signed-off-by: Maximilian Heyne <mheyne@amazon.de>
Fixes: d0b075ffee ("xen/events: Refactor evtchn_to_irq array to be dynamically allocated")
Link: https://lore.kernel.org/r/20210812130930.127134-1-mheyne@amazon.de
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 3de218ff39b9e3f0d453fe3154f12a174de44b25 upstream.
In order to avoid a race condition for user events when changing
cpu affinity reset the active flag only when EOI-ing the event.
This is working fine as all user events are lateeoi events. Note that
lateeoi_ack_mask_dynirq() is not modified as there is no explicit call
to xen_irq_lateeoi() expected later.
Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Fixes: b6622798bc50b62 ("xen/events: avoid handling the same event on two cpus at the same time")
Tested-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrvsky@oracle.com>
Link: https://lore.kernel.org/r/20210623130913.9405-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The commit referenced below was incomplete: It merely affected what
would get written to the vdev-<N> xenstore node. The guest would still
find the function at the original function number as long as
__xen_pcibk_get_pci_dev() wouldn't be in sync. The same goes for AER wrt
__xen_pcibk_get_pcifront_dev().
Undo overriding the function to zero and instead make sure that VFs at
function zero remain alone in their slot. This has the added benefit of
improving overall capacity, considering that there's only a total of 32
slots available right now (PCI segment and bus can both only ever be
zero at present).
This is upstream commit 4ba50e7c423c29639878c00573288869aa627068.
Fixes: 8a5248fe10 ("xen PV passthru: assign SR-IOV virtual functions to
separate virtual slots")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/8def783b-404c-3452-196d-3f3fd4d72c9e@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c81d3d24602540f65256f98831d0a25599ea6b87 upstream.
When multiple PCI devices get assigned to a guest right at boot, libxl
incrementally populates the backend tree. The writes for the first of
the devices trigger the backend watch. In turn xen_pcibk_setup_backend()
will set the XenBus state to Initialised, at which point no further
reconfigures would happen unless a device got hotplugged. Arrange for
reconfigure to also get triggered from the backend watch handler.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/2337cbd6-94b9-4187-9862-c03ea12e0c61@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The backport of upstream patch 25da4618af240fbec61 ("xen/events: don't
unmask an event channel when an eoi is pending") introduced a
regression for stable kernels 5.10 and older: setting IRQ affinity for
IRQs related to interdomain events would no longer work, as moving the
IRQ to its new cpu was not included in the irq_ack callback for those
events.
Fix that by adding the needed call.
Note that kernels 5.11 and later don't need the explicit moving of the
IRQ to the target cpu in the irq_ack callback, due to a rework of the
affinity setting in kernel 5.11.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d120198bd5ff1d41808b6914e1eb89aff937415c upstream.
Unmask operation must be called with interrupt disabled,
on preempt_rt spin_lock_irqsave/spin_unlock_irqrestore
don't disable/enable interrupts, so use raw_* implementation
and change lock variable in struct irq_info from spinlock_t
to raw_spinlock_t
Cc: stable@vger.kernel.org
Fixes: 25da4618af24 ("xen/events: don't unmask an event channel when an eoi is pending")
Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/20210406105105.10141-1-luca.fancellu@arm.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b6622798bc50b625a1e62f82c7190df40c1f5b21 upstream.
When changing the cpu affinity of an event it can happen today that
(with some unlucky timing) the same event will be handled on the old
and the new cpu at the same time.
Avoid that by adding an "event active" flag to the per-event data and
call the handler only if this flag isn't set.
Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Link: https://lore.kernel.org/r/20210306161833.4552-4-jgross@suse.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 25da4618af240fbec6112401498301a6f2bc9702 upstream.
An event channel should be kept masked when an eoi is pending for it.
When being migrated to another cpu it might be unmasked, though.
In order to avoid this keep three different flags for each event channel
to be able to distinguish "normal" masking/unmasking from eoi related
masking/unmasking and temporary masking. The event channel should only
be able to generate an interrupt if all flags are cleared.
Cc: stable@vger.kernel.org
Fixes: 54c9de89895e ("xen/events: add a new "late EOI" evtchn framework")
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Tested-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Link: https://lore.kernel.org/r/20210306161833.4552-3-jgross@suse.com
[boris -- corrected Fixed tag format]
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9e77d96b8e2724ed00380189f7b0ded61113b39f upstream.
When creating a new event channel with 2-level events the affinity
needs to be reset initially in order to avoid using an old affinity
from earlier usage of the event channel port. So when tearing an event
channel down reset all affinity bits.
The same applies to the affinity when onlining a vcpu: all old
affinity settings for this vcpu must be reset. As percpu events get
initialized before the percpu event channel hook is called,
resetting of the affinities happens after offlining a vcpu (this is
working, as initial percpu memory is zeroed out).
Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Link: https://lore.kernel.org/r/20210306161833.4552-2-jgross@suse.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7c77474b2d22176d2bfb592ec74e0f2cb71352c9 upstream.
In particular -ENOMEM may come back here, from set_foreign_p2m_mapping().
Don't make problems worse, the more that handling elsewhere (together
with map's status fields now indicating whether a mapping wasn't even
attempted, and hence has to be considered failed) doesn't require this
odd way of dealing with errors.
This is part of XSA-362.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ebee0eab08594b2bd5db716288a4f1ae5936e9bc upstream.
Failure of the kernel part of the mapping operation should also be
indicated as an error to the caller, or else it may assume the
respective kernel VA is okay to access.
Furthermore gnttab_map_refs() failing still requires recording
successfully mapped handles, so they can be unmapped subsequently. This
in turn requires there to be a way to tell full hypercall failure from
partial success - preset map_op status fields such that they won't
"happen" to look as if the operation succeeded.
Also again use GNTST_okay instead of implying its value (zero).
This is part of XSA-361.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit dbe5283605b3bc12ca45def09cc721a0a5c853a2 upstream.
We may not skip setting the field in the unmap structure when
GNTMAP_device_map is in use - such an unmap would fail to release the
respective resources (a page ref in the hypervisor). Otoh the field
doesn't need setting at all when GNTMAP_device_map is not in use.
To record the value for unmapping, we also better don't use our local
p2m: In particular after a subsequent change it may not have got updated
for all the batch elements. Instead it can simply be taken from the
respective map's results.
We can additionally avoid playing this game altogether for the kernel
part of the mappings in (x86) PV mode.
This is part of XSA-361.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c4295ab0b485b8bc50d2264bcae2acd06f25caaf upstream.
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 <iwj@xenproject.org>
Signed-off-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20210210170654.5377-1-julien@xen.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5f46400f7a6a4fad635d5a79e2aa5a04a30ffea1 upstream.
In commit 3499ba8198ca ("xen: Fix event channel callback via INTX/GSI")
I reworked the triggering of xenbus_probe().
I tried to simplify things by taking out the workqueue based startup
triggered from wake_waiting(); the somewhat poorly named xenbus IRQ
handler.
I missed the fact that in the XS_LOCAL case (Dom0 starting its own
xenstored or xenstore-stubdom, which happens after the kernel is booted
completely), that IRQ-based trigger is still actually needed.
So... put it back, except more cleanly. By just spawning a xenbus_probe
thread which waits on xb_waitq and runs the probe the first time it
gets woken, just as the workqueue-based hack did.
This is actually a nicer approach for *all* the back ends with different
interrupt methods, and we can switch them all over to that without the
complex conditions for when to trigger it. But not in -rc6. This is
the minimal fix for the regression, although it's a step in the right
direction instead of doing a partial revert and actually putting the
workqueue back. It's also simpler than the workqueue.
Fixes: 3499ba8198ca ("xen: Fix event channel callback via INTX/GSI")
Reported-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/4c9af052a6e0f6485d1de43f2c38b1461996db99.camel@infradead.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Cc: Salvatore Bonaccorso <carnil@debian.org>
Cc: Jason Andryuk <jandryuk@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ef3a575baf53571dc405ee4028e26f50856898e7 upstream.
Allow issuing an IOCTL_PRIVCMD_MMAP_RESOURCE ioctl with num = 0 and
addr = 0 in order to fetch the size of a specific resource.
Add a shortcut to the default map resource path, since fetching the
size requires no address to be passed in, and thus no VMA to setup.
This is missing from the initial implementation, and causes issues
when mapping resources that don't have fixed or known sizes.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Tested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: stable@vger.kernel.org # >= 4.18
Link: https://lore.kernel.org/r/20210112115358.23346-1-roger.pau@citrix.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 3499ba8198cad47b731792e5e56b9ec2a78a83a2 ]
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 <dwmw@amazon.co.uk>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20210113132606.422794-2-dwmw2@infradead.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 779055842da5b2e508f3ccf9a8153cb1f704f566 upstream.
There seems to be a bug in the original code when gntdev_get_page()
is called with writeable=true then the page needs to be marked dirty
before being put.
To address this, a bool writeable is added in gnt_dev_copy_batch, set
it in gntdev_grant_copy_seg() (and drop `writeable` argument to
gntdev_get_page()) and then, based on batch->writeable, use
set_page_dirty_lock().
Fixes: a4cdb556ca (xen/gntdev: add ioctl for grant copy)
Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/1599375114-32360-1-git-send-email-jrdr.linux@gmail.com
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
[jinoh: backport accounting for missing
commit 73b0140bf0fe ("mm/gup: change GUP fast to use flags rather than a write 'bool'")]
Signed-off-by: Jinoh Kang <jinoh.kang.kr@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9996bd494794a2fe393e97e7a982388c6249aa76 upstream.
'xenbus_backend' watches 'state' of devices, which is writable by
guests. Hence, if guests intensively updates it, dom0 will have lots of
pending events that exhausting memory of dom0. In other words, guests
can trigger dom0 memory pressure. This is known as XSA-349. However,
the watch callback of it, 'frontend_changed()', reads only 'state', so
doesn't need to have the pending events.
To avoid the problem, this commit disallows pending watch messages for
'xenbus_backend' using the 'will_handle()' watch callback.
This is part of XSA-349
Cc: stable@vger.kernel.org
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reported-by: Michael Kurth <mku@amazon.de>
Reported-by: Pawel Wieczorkiewicz <wipawel@amazon.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3dc86ca6b4c8cfcba9da7996189d1b5a358a94fc upstream.
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 <sjpark@amazon.de>
Reported-by: Michael Kurth <mku@amazon.de>
Reported-by: Pawel Wieczorkiewicz <wipawel@amazon.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit be987200fbaceaef340872841d4f7af2c5ee8dc3 upstream.
This commit adds support of the 'will_handle' watch callback for
'xen_bus_type' users.
This is part of XSA-349
Cc: stable@vger.kernel.org
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reported-by: Michael Kurth <mku@amazon.de>
Reported-by: Pawel Wieczorkiewicz <wipawel@amazon.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 2e85d32b1c865bec703ce0c962221a5e955c52c2 upstream.
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 <sjpark@amazon.de>
Reported-by: Michael Kurth <mku@amazon.de>
Reported-by: Pawel Wieczorkiewicz <wipawel@amazon.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit fed1755b118147721f2c87b37b9d66e62c39b668 upstream.
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 <sjpark@amazon.de>
Reported-by: Michael Kurth <mku@amazon.de>
Reported-by: Pawel Wieczorkiewicz <wipawel@amazon.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5f7f77400ab5b357b5fdb7122c3442239672186c upstream.
In order to avoid high dom0 load due to rogue guests sending events at
high frequency, block those events in case there was no action needed
in dom0 to handle the events.
This is done by adding a per-event counter, which set to zero in case
an EOI without the XEN_EOI_FLAG_SPURIOUS is received from a backend
driver, and incremented when this flag has been set. In case the
counter is 2 or higher delay the EOI by 1 << (cnt - 2) jiffies, but
not more than 1 second.
In order not to waste memory shorten the per-event refcnt to two bytes
(it should normally never exceed a value of 2). Add an overflow check
to evtchn_get() to make sure the 2 bytes really won't overflow.
This is part of XSA-332.
Cc: stable@vger.kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Wei Liu <wl@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e99502f76271d6bc4e374fe368c50c67a1fd3070 upstream.
In case rogue guests are sending events at high frequency it might
happen that xen_evtchn_do_upcall() won't stop processing events in
dom0. As this is done in irq handling a crash might be the result.
In order to avoid that, delay further inter-domain events after some
time in xen_evtchn_do_upcall() by forcing eoi processing into a
worker on the same cpu, thus inhibiting new events coming in.
The time after which eoi processing is to be delayed is configurable
via a new module parameter "event_loop_timeout" which specifies the
maximum event loop time in jiffies (default: 2, the value was chosen
after some tests showing that a value of 2 was the lowest with an
only slight drop of dom0 network throughput while multiple guests
performed an event storm).
How long eoi processing will be delayed can be specified via another
parameter "event_eoi_delay" (again in jiffies, default 10, again the
value was chosen after testing with different delay values).
This is part of XSA-332.
Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Wei Liu <wl@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7beb290caa2adb0a399e735a1e175db9aae0523a upstream.
Today only fifo event channels have a cpu hotplug callback. In order
to prepare for more percpu (de)init work move that callback into
events_base.c and add percpu_init() and percpu_deinit() hooks to
struct evtchn_ops.
This is part of XSA-332.
Cc: stable@vger.kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wl@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c44b849cee8c3ac587da3b0980e01f77500d158c upstream.
Instead of disabling the irq when an event is received and enabling
it again when handled by the user process use the lateeoi model.
This is part of XSA-332.
Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wl@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c2711441bc961b37bba0615dd7135857d189035f upstream.
In order to reduce the chance for the system becoming unresponsive due
to event storms triggered by a misbehaving pcifront use the lateeoi irq
binding for pciback and unmask the event channel only just before
leaving the event handling function.
Restructure the handling to support that scheme. Basically an event can
come in for two reasons: either a normal request for a pciback action,
which is handled in a worker, or in case the guest has finished an AER
request which was requested by pciback.
When an AER request is issued to the guest and a normal pciback action
is currently active issue an EOI early in order to be able to receive
another event when the AER request has been finished by the guest.
Let the worker processing the normal requests run until no further
request is pending, instead of starting a new worker ion that case.
Issue the EOI only just before leaving the worker.
This scheme allows to drop calling the generic function
xen_pcibk_test_and_schedule_op() after processing of any request as
the handling of both request types is now separated more cleanly.
This is part of XSA-332.
Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wl@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c8d647a326f06a39a8e5f0f1af946eacfa1835f8 upstream.
In order to reduce the chance for the system becoming unresponsive due
to event storms triggered by a misbehaving pvcallsfront use the lateeoi
irq binding for pvcallsback and unmask the event channel only after
handling all write requests, which are the ones coming in via an irq.
This requires modifying the logic a little bit to not require an event
for each write request, but to keep the ioworker running until no
further data is found on the ring page to be processed.
This is part of XSA-332.
Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Wei Liu <wl@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 86991b6e7ea6c613b7692f65106076943449b6b7 upstream.
In order to reduce the chance for the system becoming unresponsive due
to event storms triggered by a misbehaving scsifront use the lateeoi
irq binding for scsiback and unmask the event channel only just before
leaving the event handling function.
In case of a ring protocol error don't issue an EOI in order to avoid
the possibility to use that for producing an event storm. This at once
will result in no further call of scsiback_irq_fn(), so the ring_error
struct member can be dropped and scsiback_do_cmd_fn() can signal the
protocol error via a negative return value.
This is part of XSA-332.
Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wl@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
