linux-stable.git/drivers/xen, branch v5.4.71

xen/xenbus: Fix granting of vmalloc'd memory

2020-09-09T17:12:22+00:00

[ Upstream commit d742db70033c745e410523e00522ee0cfe2aa416 ]

On some architectures (like ARM), virt_to_gfn cannot be used for
vmalloc'd memory because of its reliance on virt_to_phys. This patch
introduces a check for vmalloc'd addresses and obtains the PFN using
vmalloc_to_pfn in that case.

Signed-off-by: Simon Leiner 
Reviewed-by: Stefano Stabellini 
Link: https://lore.kernel.org/r/20200825093153.35500-1-simon@leiner.me
Signed-off-by: Juergen Gross 
Signed-off-by: Sasha Levin

XEN uses irqdesc::irq_data_common::handler_data to store a per interrupt XEN data pointer which contains XEN specific information.

2020-09-03T09:27:04+00:00

commit c330fb1ddc0a922f044989492b7fcca77ee1db46 upstream.

handler data is meant for interrupt handlers and not for storing irq chip
specific information as some devices require handler data to store internal
per interrupt information, e.g. pinctrl/GPIO chained interrupt handlers.

This obviously creates a conflict of interests and crashes the machine
because the XEN pointer is overwritten by the driver pointer.

As the XEN data is not handler specific it should be stored in
irqdesc::irq_data::chip_data instead.

A simple sed s/irq_[sg]et_handler_data/irq_[sg]et_chip_data/ cures that.

Cc: stable@vger.kernel.org
Reported-by: Roman Shaposhnik 
Signed-off-by: Thomas Gleixner 
Tested-by: Roman Shaposhnik 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/87lfi2yckt.fsf@nanos.tec.linutronix.de
Signed-off-by: Juergen Gross 
Signed-off-by: Greg Kroah-Hartman

xen: don't reschedule in preemption off sections

2020-08-26T08:41:07+00:00

For support of long running hypercalls xen_maybe_preempt_hcall() is
calling cond_resched() in case a hypercall marked as preemptible has
been interrupted.

Normally this is no problem, as only hypercalls done via some ioctl()s
are marked to be preemptible. In rare cases when during such a
preemptible hypercall an interrupt occurs and any softirq action is
started from irq_exit(), a further hypercall issued by the softirq
handler will be regarded to be preemptible, too. This might lead to
rescheduling in spite of the softirq handler potentially having set
preempt_disable(), leading to splats like:

BUG: sleeping function called from invalid context at drivers/xen/preempt.c:37
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 20775, name: xl
INFO: lockdep is turned off.
CPU: 1 PID: 20775 Comm: xl Tainted: G D W 5.4.46-1_prgmr_debug.el7.x86_64 #1
Call Trace:

dump_stack+0x8f/0xd0
___might_sleep.cold.76+0xb2/0x103
xen_maybe_preempt_hcall+0x48/0x70
xen_do_hypervisor_callback+0x37/0x40
RIP: e030:xen_hypercall_xen_version+0xa/0x20
Code: ...
RSP: e02b:ffffc900400dcc30 EFLAGS: 00000246
RAX: 000000000004000d RBX: 0000000000000200 RCX: ffffffff8100122a
RDX: ffff88812e788000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffffff83ee3ad0 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: ffff8881824aa0b0
R13: 0000000865496000 R14: 0000000865496000 R15: ffff88815d040000
? xen_hypercall_xen_version+0xa/0x20
? xen_force_evtchn_callback+0x9/0x10
? check_events+0x12/0x20
? xen_restore_fl_direct+0x1f/0x20
? _raw_spin_unlock_irqrestore+0x53/0x60
? debug_dma_sync_single_for_cpu+0x91/0xc0
? _raw_spin_unlock_irqrestore+0x53/0x60
? xen_swiotlb_sync_single_for_cpu+0x3d/0x140
? mlx4_en_process_rx_cq+0x6b6/0x1110 [mlx4_en]
? mlx4_en_poll_rx_cq+0x64/0x100 [mlx4_en]
? net_rx_action+0x151/0x4a0
? __do_softirq+0xed/0x55b
? irq_exit+0xea/0x100
? xen_evtchn_do_upcall+0x2c/0x40
? xen_do_hypervisor_callback+0x29/0x40

? xen_hypercall_domctl+0xa/0x20
? xen_hypercall_domctl+0x8/0x20
? privcmd_ioctl+0x221/0x990 [xen_privcmd]
? do_vfs_ioctl+0xa5/0x6f0
? ksys_ioctl+0x60/0x90
? trace_hardirqs_off_thunk+0x1a/0x20
? __x64_sys_ioctl+0x16/0x20
? do_syscall_64+0x62/0x250
? entry_SYSCALL_64_after_hwframe+0x49/0xbe

Fix that by testing preempt_count() before calling cond_resched().

In kernel 5.8 this can't happen any more due to the entry code rework
(more than 100 patches, so not a candidate for backporting).

The issue was introduced in kernel 4.3, so this patch should go into
all stable kernels in [4.3 ... 5.7].

Reported-by: Sarah Newman 
Fixes: 0fa2f5cb2b0ecd8 ("sched/preempt, xen: Use need_resched() instead of should_resched()")
Cc: Sarah Newman 
Cc: stable@vger.kernel.org
Signed-off-by: Juergen Gross 
Tested-by: Chris Brannon 
Signed-off-by: Greg Kroah-Hartman

swiotlb-xen: use vmalloc_to_page on vmalloc virt addresses

2020-08-26T08:40:56+00:00

[ Upstream commit 8b1e868f66076490189a36d984fcce286cdd6295 ]

xen_alloc_coherent_pages might return pages for which virt_to_phys and
virt_to_page don't work, e.g. ioremap'ed pages.

So in xen_swiotlb_free_coherent we can't assume that virt_to_page works.
Instead add a is_vmalloc_addr check and use vmalloc_to_page on vmalloc
virt addresses.

This patch fixes the following crash at boot on RPi4 (the underlying
issue is not RPi4 specific):
https://marc.info/?l=xen-devel&m=158862573216800

Signed-off-by: Boris Ostrovsky 
Signed-off-by: Stefano Stabellini 
Reviewed-by: Boris Ostrovsky 
Tested-by: Corey Minyard 
Tested-by: Roman Shaposhnik 
Link: https://lore.kernel.org/r/20200710223427.6897-1-sstabellini@kernel.org
Signed-off-by: Juergen Gross 
Signed-off-by: Sasha Levin

xen/gntdev: Fix dmabuf import with non-zero sgt offset

2020-08-19T06:16:29+00:00

commit 5fa4e6f1c2d8c9a4e47e1931b42893172d388f2b upstream.

It is possible that the scatter-gather table during dmabuf import has
non-zero offset of the data, but user-space doesn't expect that.
Fix this by failing the import, so user-space doesn't access wrong data.

Fixes: bf8dc55b1358 ("xen/gntdev: Implement dma-buf import functionality")

Signed-off-by: Oleksandr Andrushchenko 
Acked-by: Juergen Gross 
Cc: 
Link: https://lore.kernel.org/r/20200813062113.11030-2-andr2000@gmail.com
Signed-off-by: Juergen Gross 
Signed-off-by: Greg Kroah-Hartman

xen/balloon: make the balloon wait interruptible

2020-08-19T06:16:29+00:00

commit 88a479ff6ef8af7f07e11593d58befc644244ff7 upstream.

So it can be killed, or else processes can get hung indefinitely
waiting for balloon pages.

Signed-off-by: Roger Pau Monné 
Reviewed-by: Juergen Gross 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200727091342.52325-3-roger.pau@citrix.com
Signed-off-by: Juergen Gross 
Signed-off-by: Greg Kroah-Hartman

xen/balloon: fix accounting in alloc_xenballooned_pages error path

2020-08-19T06:16:28+00:00

commit 1951fa33ec259abdf3497bfee7b63e7ddbb1a394 upstream.

target_unpopulated is incremented with nr_pages at the start of the
function, but the call to free_xenballooned_pages will only subtract
pgno number of pages, and thus the rest need to be subtracted before
returning or else accounting will be skewed.

Signed-off-by: Roger Pau Monné 
Reviewed-by: Juergen Gross 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200727091342.52325-2-roger.pau@citrix.com
Signed-off-by: Juergen Gross 
Signed-off-by: Greg Kroah-Hartman

xen/pvcalls-back: test for errors when calling backend_connect()

2020-06-17T14:40:38+00:00

commit c8d70a29d6bbc956013f3401f92a4431a9385a3c upstream.

backend_connect() can fail, so switch the device to connected only if
no error occurred.

Fixes: 0a9c75c2c7258f2 ("xen/pvcalls: xenbus state handling")
Cc: stable@vger.kernel.org
Signed-off-by: Juergen Gross 
Link: https://lore.kernel.org/r/20200511074231.19794-1-jgross@suse.com
Reviewed-by: Stefano Stabellini 
Signed-off-by: Boris Ostrovsky 
Signed-off-by: Greg Kroah-Hartman

xen/xenbus: ensure xenbus_map_ring_valloc() returns proper grant status

2020-05-02T06:48:57+00:00

[ Upstream commit 6b51fd3f65a22e3d1471b18a1d56247e246edd46 ]

xenbus_map_ring_valloc() maps a ring page and returns the status of the
used grant (0 meaning success).

There are Xen hypervisors which might return the value 1 for the status
of a failed grant mapping due to a bug. Some callers of
xenbus_map_ring_valloc() test for errors by testing the returned status
to be less than zero, resulting in no error detected and crashing later
due to a not available ring page.

Set the return value of xenbus_map_ring_valloc() to GNTST_general_error
in case the grant status reported by Xen is greater than zero.

This is part of XSA-316.

Signed-off-by: Juergen Gross 
Reviewed-by: Wei Liu 
Link: https://lore.kernel.org/r/20200326080358.1018-1-jgross@suse.com
Signed-off-by: Juergen Gross 
Signed-off-by: Sasha Levin

xenbus: req->err should be updated before req->state

2020-03-25T07:25:49+00:00

[ Upstream commit 8130b9d5b5abf26f9927b487c15319a187775f34 ]

This patch adds the barrier to guarantee that req->err is always updated
before req->state.

Otherwise, read_reply() would not return ERR_PTR(req->err) but
req->body, when process_writes()->xb_write() is failed.

Signed-off-by: Dongli Zhang 
Link: https://lore.kernel.org/r/20200303221423.21962-2-dongli.zhang@oracle.com
Reviewed-by: Julien Grall 
Signed-off-by: Boris Ostrovsky 
Signed-off-by: Sasha Levin