[ Upstream commit 1c682593096a487fd9aebc079a307ff7a6d054a3 ]
irqfd_wakeup() gets EPOLLHUP, when it is called by
eventfd_release() by way of wake_up_poll(&ctx->wqh, EPOLLHUP), which
gets called under spin_lock_irqsave(). We can't use a mutex here as it
will lead to a deadlock.
Fix it by switching over to a spin lock.
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/a66d7a7a9001424d432f52a9fc3931a1f345464f.1718703669.git.viresh.kumar@linaro.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a3607581cd49c17128a486a526a36a97bafcb2bb ]
Currently, the late XenStore init protocol is only triggered properly
for the case that HVM_PARAM_STORE_PFN is ~0ULL (invalid). For the
case that XenStore interface is allocated but not ready (the connection
status is not XENSTORE_CONNECTED), Linux should also wait until the
XenStore is set up properly.
Introduce a macro to describe the XenStore interface is ready, use
it in xenbus_probe_initcall() to select the code path of doing the
late XenStore init protocol or not. Since now we have more than one
condition for XenStore late init, rework the check in xenbus_probe()
for the free_irq().
Take the opportunity to enhance the check of the allocated XenStore
interface can be properly mapped, and return error early if the
memremap() fails.
Fixes: 5b3353949e ("xen: add support for initializing xenstore later as HVM domain")
Signed-off-by: Henry Wang <xin.wang2@amd.com>
Signed-off-by: Michal Orzel <michal.orzel@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20240517011516.1451087-1-xin.wang2@amd.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 38620fc4e8934f1801c7811ef39a041914ac4c1d ]
When running as PVH or HVM Linux will use holes in the memory map as scratch
space to map grants, foreign domain pages and possibly miscellaneous other
stuff. However the usage of such memory map holes for Xen purposes can be
problematic. The request of holesby Xen happen quite early in the kernel boot
process (grant table setup already uses scratch map space), and it's possible
that by then not all devices have reclaimed their MMIO space. It's not
unlikely for chunks of Xen scratch map space to end up using PCI bridge MMIO
window memory, which (as expected) causes quite a lot of issues in the system.
At least for PVH dom0 we have the possibility of using regions marked as
UNUSABLE in the e820 memory map. Either if the region is UNUSABLE in the
native memory map, or it has been converted into UNUSABLE in order to hide RAM
regions from dom0, the second stage translation page-tables can populate those
areas without issues.
PV already has this kind of logic, where the balloon driver is inflated at
boot. Re-use the current logic in order to also inflate it when running as
PVH. onvert UNUSABLE regions up to the ratio specified in EXTRA_MEM_RATIO to
RAM, while reserving them using xen_add_extra_mem() (which is also moved so
it's no longer tied to CONFIG_PV).
[jgross: fixed build for CONFIG_PVH without CONFIG_XEN_PVH]
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20240220174341.56131-1-roger.pau@citrix.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d277f9d82802223f242cd9b60c988cfdda1d6be0 ]
In bind_evtchn_to_irq_chip() don't increment the refcnt of the event
channel blindly. In case the event channel is NOT refcounted, issue a
warning instead.
Add an additional safety net by doing the refcnt increment only if the
caller has specified IRQF_SHARED in the irqflags parameter.
Fixes: 9e90e58c11b7 ("xen: evtchn: Allow shared registration of IRQ handers")
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Link: https://lore.kernel.org/r/20240313071409.25913-3-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 51c23bd691c0f1fb95b29731c356c6fd69925d17 ]
When unbinding a user event channel, the related handler might be
called a last time in case the kernel was built with
CONFIG_DEBUG_SHIRQ. This might cause a WARN() in the handler.
Avoid that by adding an "unbinding" flag to struct user_event which
will short circuit the handler.
Fixes: 9e90e58c11b7 ("xen: evtchn: Allow shared registration of IRQ handers")
Reported-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Tested-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Link: https://lore.kernel.org/r/20240313071409.25913-2-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit fa765c4b4aed2d64266b694520ecb025c862c5a9 ]
shutdown_pirq and startup_pirq are not taking the
irq_mapping_update_lock because they can't due to lock inversion. Both
are called with the irq_desc->lock being taking. The lock order,
however, is first irq_mapping_update_lock and then irq_desc->lock.
This opens multiple races:
- shutdown_pirq can be interrupted by a function that allocates an event
channel:
CPU0 CPU1
shutdown_pirq {
xen_evtchn_close(e)
__startup_pirq {
EVTCHNOP_bind_pirq
-> returns just freed evtchn e
set_evtchn_to_irq(e, irq)
}
xen_irq_info_cleanup() {
set_evtchn_to_irq(e, -1)
}
}
Assume here event channel e refers here to the same event channel
number.
After this race the evtchn_to_irq mapping for e is invalid (-1).
- __startup_pirq races with __unbind_from_irq in a similar way. Because
__startup_pirq doesn't take irq_mapping_update_lock it can grab the
evtchn that __unbind_from_irq is currently freeing and cleaning up. In
this case even though the event channel is allocated, its mapping can
be unset in evtchn_to_irq.
The fix is to first cleanup the mappings and then close the event
channel. In this way, when an event channel gets allocated it's
potential previous evtchn_to_irq mappings are guaranteed to be unset already.
This is also the reverse order of the allocation where first the event
channel is allocated and then the mappings are setup.
On a 5.10 kernel prior to commit 3fcdaf3d7634 ("xen/events: modify internal
[un]bind interfaces"), we hit a BUG like the following during probing of NVMe
devices. The issue is that during nvme_setup_io_queues, pci_free_irq
is called for every device which results in a call to shutdown_pirq.
With many nvme devices it's therefore likely to hit this race during
boot because there will be multiple calls to shutdown_pirq and
startup_pirq are running potentially in parallel.
------------[ cut here ]------------
blkfront: xvda: barrier or flush: disabled; persistent grants: enabled; indirect descriptors: enabled; bounce buffer: enabled
kernel BUG at drivers/xen/events/events_base.c:499!
invalid opcode: 0000 [#1] SMP PTI
CPU: 44 PID: 375 Comm: kworker/u257:23 Not tainted 5.10.201-191.748.amzn2.x86_64 #1
Hardware name: Xen HVM domU, BIOS 4.11.amazon 08/24/2006
Workqueue: nvme-reset-wq nvme_reset_work
RIP: 0010:bind_evtchn_to_cpu+0xdf/0xf0
Code: 5d 41 5e c3 cc cc cc cc 44 89 f7 e8 2b 55 ad ff 49 89 c5 48 85 c0 0f 84 64 ff ff ff 4c 8b 68 30 41 83 fe ff 0f 85 60 ff ff ff <0f> 0b 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 0f 1f 44 00 00
RSP: 0000:ffffc9000d533b08 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000006
RDX: 0000000000000028 RSI: 00000000ffffffff RDI: 00000000ffffffff
RBP: ffff888107419680 R08: 0000000000000000 R09: ffffffff82d72b00
R10: 0000000000000000 R11: 0000000000000000 R12: 00000000000001ed
R13: 0000000000000000 R14: 00000000ffffffff R15: 0000000000000002
FS: 0000000000000000(0000) GS:ffff88bc8b500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000002610001 CR4: 00000000001706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
? show_trace_log_lvl+0x1c1/0x2d9
? show_trace_log_lvl+0x1c1/0x2d9
? set_affinity_irq+0xdc/0x1c0
? __die_body.cold+0x8/0xd
? die+0x2b/0x50
? do_trap+0x90/0x110
? bind_evtchn_to_cpu+0xdf/0xf0
? do_error_trap+0x65/0x80
? bind_evtchn_to_cpu+0xdf/0xf0
? exc_invalid_op+0x4e/0x70
? bind_evtchn_to_cpu+0xdf/0xf0
? asm_exc_invalid_op+0x12/0x20
? bind_evtchn_to_cpu+0xdf/0xf0
? bind_evtchn_to_cpu+0xc5/0xf0
set_affinity_irq+0xdc/0x1c0
irq_do_set_affinity+0x1d7/0x1f0
irq_setup_affinity+0xd6/0x1a0
irq_startup+0x8a/0xf0
__setup_irq+0x639/0x6d0
? nvme_suspend+0x150/0x150
request_threaded_irq+0x10c/0x180
? nvme_suspend+0x150/0x150
pci_request_irq+0xa8/0xf0
? __blk_mq_free_request+0x74/0xa0
queue_request_irq+0x6f/0x80
nvme_create_queue+0x1af/0x200
nvme_create_io_queues+0xbd/0xf0
nvme_setup_io_queues+0x246/0x320
? nvme_irq_check+0x30/0x30
nvme_reset_work+0x1c8/0x400
process_one_work+0x1b0/0x350
worker_thread+0x49/0x310
? process_one_work+0x350/0x350
kthread+0x11b/0x140
? __kthread_bind_mask+0x60/0x60
ret_from_fork+0x22/0x30
Modules linked in:
---[ end trace a11715de1eee1873 ]---
Fixes: d46a78b05c ("xen: implement pirq type event channels")
Cc: stable@vger.kernel.org
Co-debugged-by: Andrew Panyakin <apanyaki@amazon.com>
Signed-off-by: Maximilian Heyne <mheyne@amazon.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20240124163130.31324-1-mheyne@amazon.de
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 3fcdaf3d7634338c3f5cbfa7451eb0b6b0024844 ]
Modify the internal bind- and unbind-interfaces to take a struct
irq_info parameter. When allocating a new IRQ pass the pointer from
the allocating function further up.
This will reduce the number of info_for_irq() calls and make the code
more efficient.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Stable-dep-of: fa765c4b4aed ("xen/events: close evtchn after mapping cleanup")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 5dd9ad32d7758b1a76742f394acf0eb3ac8a636a ]
Instead of having a common function for allocating a single IRQ or a
consecutive number of IRQs, split up the functionality into the callers
of xen_allocate_irqs_dynamic().
This allows to handle any allocation error in xen_irq_init() gracefully
instead of panicing the system. Let xen_irq_init() return the irq_info
pointer or NULL in case of an allocation error.
Additionally set the IRQ into irq_info already at allocation time, as
otherwise the IRQ would be '0' (which is a valid IRQ number) until
being set.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Stable-dep-of: fa765c4b4aed ("xen/events: close evtchn after mapping cleanup")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 3bdb0ac350fe5e6301562143e4573971dd01ae0b ]
The helper functions type_from_irq() and cpu_from_irq() are just one
line functions used only internally.
Open code them where needed. At the same time modify and rename
get_evtchn_to_irq() to return a struct irq_info instead of the IRQ
number.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Stable-dep-of: fa765c4b4aed ("xen/events: close evtchn after mapping cleanup")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 686464514fbebb6c8de4415238319e414c3500a4 ]
get_evtchn_to_irq() has only one external user while irq_from_evtchn()
provides the same functionality and is exported for a wider user base.
Modify the only external user of get_evtchn_to_irq() to use
irq_from_evtchn() instead and make get_evtchn_to_irq() static.
evtchn_from_irq() and irq_from_virq() have a single external user and
can easily be combined to a new helper irq_evtchn_from_virq() allowing
to drop irq_from_virq() and to make evtchn_from_irq() static.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Stable-dep-of: fa765c4b4aed ("xen/events: close evtchn after mapping cleanup")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 9e90e58c11b74c2bddac4b2702cf79d36b981278 ]
Currently the handling of events is supported either in the kernel or
userspace, but not both.
In order to support fast delivery of interrupts from the guest to the
backend, we need to handle the Queue notify part of Virtio protocol in
kernel and the rest in userspace.
Update the interrupt handler registration flag to IRQF_SHARED for event
channels, which would allow multiple entities to bind their interrupt
handler for the same event channel port.
Also increment the reference count of irq_info when multiple entities
try to bind event channel to irqchip, so the unbinding happens only
after all the users are gone.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/99b1edfd3147c6b5d22a5139dab5861e767dc34a.1697439990.git.viresh.kumar@linaro.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Stable-dep-of: fa765c4b4aed ("xen/events: close evtchn after mapping cleanup")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 2d2db7d40254d5fb53b11ebd703cd1ed0c5de7a1 ]
DO NOT access the underlying struct page of an sg table exported
by DMA-buf in dmabuf_imp_to_refs(), this is not allowed.
Please see drivers/dma-buf/dma-buf.c:mangle_sg_table() for details.
Fortunately, here (for special Xen device) we can avoid using
pages and calculate gfns directly from dma addresses provided by
the sg table.
Suggested-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Acked-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Acked-by: Daniel Vetter <daniel@ffwll.ch>
Link: https://lore.kernel.org/r/20240107103426.2038075-1-olekstysh@gmail.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit bff2a2d453a1b683378b4508b86b84389f551a00 upstream.
There's a bug that when using the XEN hypervisor with bios with large
multi-page bio vectors on NVMe, the kernel deadlocks [1].
The deadlocks are caused by inability to map a large bio vector -
dma_map_sgtable always returns an error, this gets propagated to the block
layer as BLK_STS_RESOURCE and the block layer retries the request
indefinitely.
XEN uses the swiotlb framework to map discontiguous pages into contiguous
runs that are submitted to the PCIe device. The swiotlb framework has a
limitation on the length of a mapping - this needs to be announced with
the max_mapping_size method to make sure that the hardware drivers do not
create larger mappings.
Without max_mapping_size, the NVMe block driver would create large
mappings that overrun the maximum mapping size.
Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Link: https://lore.kernel.org/stable/ZTNH0qtmint%2FzLJZ@mail-itl/ [1]
Tested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Suggested-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/151bef41-e817-aea9-675-a35fdac4ed@redhat.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit bfa993b355d33a438a746523e7129391c8664e8a upstream.
The Processor capability bits notify ACPI of the OS capabilities, and
so ACPI can adjust the return of other Processor methods taking the OS
capabilities into account.
When Linux is running as a Xen dom0, the hypervisor is the entity
in charge of processor power management, and hence Xen needs to make
sure the capabilities reported by _OSC/_PDC match the capabilities of
the driver in Xen.
Introduce a small helper to sanitize the buffer when running as Xen
dom0.
When Xen supports HWP, this serves as the equivalent of commit
a21211672c ("ACPI / processor: Request native thermal interrupt
handling via _OSC") to avoid SMM crashes. Xen will set bit
ACPI_PROC_CAP_COLLAB_PROC_PERF (bit 12) in the capability bits and the
_OSC/_PDC call will apply it.
[ jandryuk: Mention Xen HWP's need. Support _OSC & _PDC ]
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Reviewed-by: Michal Wilczynski <michal.wilczynski@intel.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20231108212517.72279-1-jandryuk@gmail.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 47d970204054f859f35a2237baa75c2d84fcf436 ]
When delaying eoi handling of events, the related elements are queued
into the percpu lateeoi list. In case the list isn't empty, the
elements should be sorted by the time when eoi handling is to happen.
Unfortunately a new element will never be queued at the start of the
list, even if it has a handling time lower than all other list
elements.
Fix that by handling that case the same way as for an empty list.
Fixes: e99502f762 ("xen/events: defer eoi in case of excessive number of events")
Reported-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit e64e7c74b99ec9e439abca75f522f4b98f220bd1 ]
xen_send_IPI_one() is being used by cpuhp_report_idle_dead() after
it calls rcu_report_dead(), meaning that any RCU usage by
xen_send_IPI_one() is a bad idea.
Unfortunately xen_send_IPI_one() is using notify_remote_via_irq()
today, which is using irq_get_chip_data() via info_for_irq(). And
irq_get_chip_data() in turn is using a maple-tree lookup requiring
RCU.
Avoid this problem by caching the ipi event channels in another
percpu variable, allowing the use notify_remote_via_evtchn() in
xen_send_IPI_one().
Fixes: 721255b982 ("genirq: Use a maple tree for interrupt descriptor management")
Reported-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: David Woodhouse <dwmw@amazon.co.uk>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 2c269f42d0f382743ab230308b836ffe5ae9b2ae ]
Linux enables MSI-X before disabling INTx, but keeps MSI-X masked until
the table is filled. Then it disables INTx just before clearing MASKALL
bit. Currently this approach is rejected by xen-pciback.
According to the PCIe spec, device cannot use INTx when MSI/MSI-X is
enabled (in other words: enabling MSI/MSI-X implicitly disables INTx).
Change the logic to consider INTx disabled if MSI/MSI-X is enabled. This
applies to three places:
- checking currently enabled interrupts type,
- transition to MSI/MSI-X - where INTx would be implicitly disabled,
- clearing INTx disable bit - which can be allowed even if MSI/MSI-X is
enabled, as device should consider INTx disabled anyway in that case
Fixes: 5e29500eba ("xen-pciback: Allow setting PCI_MSIX_FLAGS_MASKALL too")
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Acked-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20231016131348.1734721-1-marmarek@invisiblethingslab.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 8dd765a5d769c521d73931850d1c8708fbc490cb ]
Using indirect pointers in an ioctl command argument means that the
layout is architecture specific, in particular we can't use the same one
from 32-bit compat tasks. The general recommendation is to have __u64
members and use u64_to_user_ptr() to access it from the kernel if we are
unable to avoid the pointers altogether.
Fixes: f8941e6c4c ("xen: privcmd: Add support for irqfd")
Reported-by: Arnd Bergmann <arnd@kernel.org>
Closes: https://lore.kernel.org/all/268a2031-63b8-4c7d-b1e5-8ab83ca80b4a@app.fastmail.com/
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/a4ef0d4a68fc858b34a81fd3f9877d9b6898eb77.1697439990.git.viresh.kumar@linaro.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 44961b81a9e9059b5c0443643915386db7035227 ]
In case an error occurs in xenbus_init(), xen_store_domain_type should
be set to XS_UNKNOWN.
Fix one instance where this action is missing.
Fixes: 5b3353949e ("xen: add support for initializing xenstore later as HVM domain")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/r/202304200845.w7m4kXZr-lkp@intel.com/
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Link: https://lore.kernel.org/r/20230822091138.4765-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
In unprivileged Xen guests event handling can cause a deadlock with
Xen console handling. The evtchn_rwlock and the hvc_lock are taken in
opposite sequence in __hvc_poll() and in Xen console IRQ handling.
Normally this is no problem, as the evtchn_rwlock is taken as a reader
in both paths, but as soon as an event channel is being closed, the
lock will be taken as a writer, which will cause read_lock() to block:
CPU0 CPU1 CPU2
(IRQ handling) (__hvc_poll()) (closing event channel)
read_lock(evtchn_rwlock)
spin_lock(hvc_lock)
write_lock(evtchn_rwlock)
[blocks]
spin_lock(hvc_lock)
[blocks]
read_lock(evtchn_rwlock)
[blocks due to writer waiting,
and not in_interrupt()]
This issue can be avoided by replacing evtchn_rwlock with RCU in
xen_free_irq(). Note that RCU is used only to delay freeing of the
irq_info memory. There is no RCU based dereferencing or replacement of
pointers involved.
In order to avoid potential races between removing the irq_info
reference and handling of interrupts, set the irq_info pointer to NULL
only when freeing its memory. The IRQ itself must be freed at that
time, too, as otherwise the same IRQ number could be allocated again
before handling of the old instance would have been finished.
This is XSA-441 / CVE-2023-34324.
Fixes: 54c9de8989 ("xen/events: add a new "late EOI" evtchn framework")
Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
There are several functions involved for performing the functionality
of evtchn_do_upcall():
- __xen_evtchn_do_upcall() doing the real work
- xen_hvm_evtchn_do_upcall() just being a wrapper for
__xen_evtchn_do_upcall(), exposed for external callers
- xen_evtchn_do_upcall() calling __xen_evtchn_do_upcall(), too, but
without any user
Simplify this maze by:
- removing the unused xen_evtchn_do_upcall()
- removing xen_hvm_evtchn_do_upcall() as the only left caller of
__xen_evtchn_do_upcall(), while renaming __xen_evtchn_do_upcall() to
xen_evtchn_do_upcall()
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Juergen Gross <jgross@suse.com>
- allow dynamic sizing of the swiotlb buffer, to cater for secure
virtualization workloads that require all I/O to be bounce buffered
(Petr Tesarik)
- move a declaration to a header (Arnd Bergmann)
- check for memory region overlap in dma-contiguous (Binglei Wang)
- remove the somewhat dangerous runtime swiotlb-xen enablement and
unexport is_swiotlb_active (Christoph Hellwig, Juergen Gross)
- per-node CMA improvements (Yajun Deng)
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Merge tag 'dma-mapping-6.6-2023-08-29' of git://git.infradead.org/users/hch/dma-mapping
Pull dma-maping updates from Christoph Hellwig:
- allow dynamic sizing of the swiotlb buffer, to cater for secure
virtualization workloads that require all I/O to be bounce buffered
(Petr Tesarik)
- move a declaration to a header (Arnd Bergmann)
- check for memory region overlap in dma-contiguous (Binglei Wang)
- remove the somewhat dangerous runtime swiotlb-xen enablement and
unexport is_swiotlb_active (Christoph Hellwig, Juergen Gross)
- per-node CMA improvements (Yajun Deng)
* tag 'dma-mapping-6.6-2023-08-29' of git://git.infradead.org/users/hch/dma-mapping:
swiotlb: optimize get_max_slots()
swiotlb: move slot allocation explanation comment where it belongs
swiotlb: search the software IO TLB only if the device makes use of it
swiotlb: allocate a new memory pool when existing pools are full
swiotlb: determine potential physical address limit
swiotlb: if swiotlb is full, fall back to a transient memory pool
swiotlb: add a flag whether SWIOTLB is allowed to grow
swiotlb: separate memory pool data from other allocator data
swiotlb: add documentation and rename swiotlb_do_find_slots()
swiotlb: make io_tlb_default_mem local to swiotlb.c
swiotlb: bail out of swiotlb_init_late() if swiotlb is already allocated
dma-contiguous: check for memory region overlap
dma-contiguous: support numa CMA for specified node
dma-contiguous: support per-numa CMA for all architectures
dma-mapping: move arch_dma_set_mask() declaration to header
swiotlb: unexport is_swiotlb_active
x86: always initialize xen-swiotlb when xen-pcifront is enabling
xen/pci: add flag for PCI passthrough being possible
Xen provides support for injecting interrupts to the guests via the
HYPERVISOR_dm_op() hypercall. The same is used by the Virtio based
device backend implementations, in an inefficient manner currently.
Generally, the Virtio backends are implemented to work with the Eventfd
based mechanism. In order to make such backends work with Xen, another
software layer needs to poll the Eventfds and raise an interrupt to the
guest using the Xen based mechanism. This results in an extra context
switch.
This is not a new problem in Linux though. It is present with other
hypervisors like KVM, etc. as well. The generic solution implemented in
the kernel for them is to provide an IOCTL call to pass the interrupt
details and eventfd, which lets the kernel take care of polling the
eventfd and raising of the interrupt, instead of handling this in user
space (which involves an extra context switch).
This patch adds support to inject a specific interrupt to guest using
the eventfd mechanism, by preventing the extra context switch.
Inspired by existing implementations for KVM, etc..
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/8e724ac1f50c2bc1eb8da9b3ff6166f1372570aa.1692697321.git.viresh.kumar@linaro.org
Signed-off-by: Juergen Gross <jgross@suse.com>
The following lockdep warning appears during boot on a Xen dom0 system:
[ 96.388794] ======================================================
[ 96.388797] WARNING: possible circular locking dependency detected
[ 96.388799] 6.4.0-rc5-default+ #8 Tainted: G EL
[ 96.388803] ------------------------------------------------------
[ 96.388804] xenconsoled/1330 is trying to acquire lock:
[ 96.388808] ffffffff82acdd10 (xs_watch_rwsem){++++}-{3:3}, at: register_xenbus_watch+0x45/0x140
[ 96.388847]
but task is already holding lock:
[ 96.388849] ffff888100c92068 (&u->msgbuffer_mutex){+.+.}-{3:3}, at: xenbus_file_write+0x2c/0x600
[ 96.388862]
which lock already depends on the new lock.
[ 96.388864]
the existing dependency chain (in reverse order) is:
[ 96.388866]
-> #2 (&u->msgbuffer_mutex){+.+.}-{3:3}:
[ 96.388874] __mutex_lock+0x85/0xb30
[ 96.388885] xenbus_dev_queue_reply+0x48/0x2b0
[ 96.388890] xenbus_thread+0x1d7/0x950
[ 96.388897] kthread+0xe7/0x120
[ 96.388905] ret_from_fork+0x2c/0x50
[ 96.388914]
-> #1 (xs_response_mutex){+.+.}-{3:3}:
[ 96.388923] __mutex_lock+0x85/0xb30
[ 96.388930] xenbus_backend_ioctl+0x56/0x1c0
[ 96.388935] __x64_sys_ioctl+0x90/0xd0
[ 96.388942] do_syscall_64+0x5c/0x90
[ 96.388950] entry_SYSCALL_64_after_hwframe+0x72/0xdc
[ 96.388957]
-> #0 (xs_watch_rwsem){++++}-{3:3}:
[ 96.388965] __lock_acquire+0x1538/0x2260
[ 96.388972] lock_acquire+0xc6/0x2b0
[ 96.388976] down_read+0x2d/0x160
[ 96.388983] register_xenbus_watch+0x45/0x140
[ 96.388990] xenbus_file_write+0x53d/0x600
[ 96.388994] vfs_write+0xe4/0x490
[ 96.389003] ksys_write+0xb8/0xf0
[ 96.389011] do_syscall_64+0x5c/0x90
[ 96.389017] entry_SYSCALL_64_after_hwframe+0x72/0xdc
[ 96.389023]
other info that might help us debug this:
[ 96.389025] Chain exists of:
xs_watch_rwsem --> xs_response_mutex --> &u->msgbuffer_mutex
[ 96.413429] Possible unsafe locking scenario:
[ 96.413430] CPU0 CPU1
[ 96.413430] ---- ----
[ 96.413431] lock(&u->msgbuffer_mutex);
[ 96.413432] lock(xs_response_mutex);
[ 96.413433] lock(&u->msgbuffer_mutex);
[ 96.413434] rlock(xs_watch_rwsem);
[ 96.413436]
*** DEADLOCK ***
[ 96.413436] 1 lock held by xenconsoled/1330:
[ 96.413438] #0: ffff888100c92068 (&u->msgbuffer_mutex){+.+.}-{3:3}, at: xenbus_file_write+0x2c/0x600
[ 96.413446]
An ioctl call IOCTL_XENBUS_BACKEND_SETUP (record #1 in the report)
results in calling xenbus_alloc() -> xs_suspend() which introduces
ordering xs_watch_rwsem --> xs_response_mutex. The xenbus_thread()
operation (record #2) creates xs_response_mutex --> &u->msgbuffer_mutex.
An XS_WATCH write to the xenbus file then results in a complain about
the opposite lock order &u->msgbuffer_mutex --> xs_watch_rwsem.
The dependency xs_watch_rwsem --> xs_response_mutex is spurious. Avoid
it and the warning by changing the ordering in xs_suspend(), first
acquire xs_response_mutex and then xs_watch_rwsem. Reverse also the
unlocking order in xs_suspend_cancel() for consistency, but keep
xs_resume() as is because it needs to have xs_watch_rwsem unlocked only
after exiting xs suspend and re-adding all watches.
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20230607123624.15739-1-petr.pavlu@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Use colon to separate parameter name from their specific meaning.
silence the warning:
drivers/xen/grant-table.c:1051: warning: Function parameter or member 'nr_pages' not described in 'gnttab_free_pages'
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=6030
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Acked-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20230731030037.123946-1-yang.lee@linux.alibaba.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Use IS_ERR_OR_NULL() to detect an error pointer or a null pointer
open-coding to simplify the code.
Signed-off-by: Li Zetao <lizetao1@huawei.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20230817014736.3094289-1-lizetao1@huawei.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Commit a92336a117 ("xen/pciback: Drop two backends, squash and cleanup some code.")
declared but never implemented these functions.
Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20230808150912.43416-1-yuehaibing@huawei.com
Signed-off-by: Juergen Gross <jgross@suse.com>
SWIOTLB implementation details should not be exposed to the rest of the
kernel. This will allow to make changes to the implementation without
modifying non-swiotlb code.
To avoid breaking existing users, provide helper functions for the few
required fields.
As a bonus, using a helper function to initialize struct device allows to
get rid of an #ifdef in driver core.
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
When a grant entry is still in use by the remote domain, Linux must put
it on a deferred list. Normally, this list is very short, because
the PV network and block protocols expect the backend to unmap the grant
first. However, Qubes OS's GUI protocol is subject to the constraints
of the X Window System, and as such winds up with the frontend unmapping
the window first. As a result, the list can grow very large, resulting
in a massive memory leak and eventual VM freeze.
To partially solve this problem, make the number of entries that the VM
will attempt to free at each iteration tunable. The default is still
10, but it can be overridden via a module parameter.
This is Cc: stable because (when combined with appropriate userspace
changes) it fixes a severe performance and stability problem for Qubes
OS users.
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/20230726165354.1252-1-demi@invisiblethingslab.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Xen 4.17 supports the creation of static evtchns. To allow user space
application to bind static evtchns introduce new ioctl
"IOCTL_EVTCHN_BIND_STATIC". Existing IOCTL doing more than binding
that’s why we need to introduce the new IOCTL to only bind the static
event channels.
Static evtchns to be available for use during the lifetime of the
guest. When the application exits, __unbind_from_irq() ends up being
called from release() file operations because of that static evtchns
are getting closed. To avoid closing the static event channel, add the
new bool variable "is_static" in "struct irq_info" to mark the event
channel static when creating the event channel to avoid closing the
static evtchn.
Also, take this opportunity to remove the open-coded version of the
evtchn close in drivers/xen/evtchn.c file and use xen_evtchn_close().
Signed-off-by: Rahul Singh <rahul.singh@arm.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/ae7329bf1713f83e4aad4f3fa0f316258c40a3e9.1689677042.git.rahul.singh@arm.com
Signed-off-by: Juergen Gross <jgross@suse.com>
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Merge tag 'for-linus-6.5-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen fixes from Juergen Gross:
- a cleanup of the Xen related ELF-notes
- a fix for virtio handling in Xen dom0 when running Xen in a VM
* tag 'for-linus-6.5-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/virtio: Fix NULL deref when a bridge of PCI root bus has no parent
x86/Xen: tidy xen-head.S
- Yosry has also eliminated cgroup's atomic rstat flushing.
- Nhat Pham adds the new cachestat() syscall. It provides userspace
with the ability to query pagecache status - a similar concept to
mincore() but more powerful and with improved usability.
- Mel Gorman provides more optimizations for compaction, reducing the
prevalence of page rescanning.
- Lorenzo Stoakes has done some maintanance work on the get_user_pages()
interface.
- Liam Howlett continues with cleanups and maintenance work to the maple
tree code. Peng Zhang also does some work on maple tree.
- Johannes Weiner has done some cleanup work on the compaction code.
- David Hildenbrand has contributed additional selftests for
get_user_pages().
- Thomas Gleixner has contributed some maintenance and optimization work
for the vmalloc code.
- Baolin Wang has provided some compaction cleanups,
- SeongJae Park continues maintenance work on the DAMON code.
- Huang Ying has done some maintenance on the swap code's usage of
device refcounting.
- Christoph Hellwig has some cleanups for the filemap/directio code.
- Ryan Roberts provides two patch series which yield some
rationalization of the kernel's access to pte entries - use the provided
APIs rather than open-coding accesses.
- Lorenzo Stoakes has some fixes to the interaction between pagecache
and directio access to file mappings.
- John Hubbard has a series of fixes to the MM selftesting code.
- ZhangPeng continues the folio conversion campaign.
- Hugh Dickins has been working on the pagetable handling code, mainly
with a view to reducing the load on the mmap_lock.
- Catalin Marinas has reduced the arm64 kmalloc() minimum alignment from
128 to 8.
- Domenico Cerasuolo has improved the zswap reclaim mechanism by
reorganizing the LRU management.
- Matthew Wilcox provides some fixups to make gfs2 work better with the
buffer_head code.
- Vishal Moola also has done some folio conversion work.
- Matthew Wilcox has removed the remnants of the pagevec code - their
functionality is migrated over to struct folio_batch.
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Merge tag 'mm-stable-2023-06-24-19-15' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull mm updates from Andrew Morton:
- Yosry Ahmed brought back some cgroup v1 stats in OOM logs
- Yosry has also eliminated cgroup's atomic rstat flushing
- Nhat Pham adds the new cachestat() syscall. It provides userspace
with the ability to query pagecache status - a similar concept to
mincore() but more powerful and with improved usability
- Mel Gorman provides more optimizations for compaction, reducing the
prevalence of page rescanning
- Lorenzo Stoakes has done some maintanance work on the
get_user_pages() interface
- Liam Howlett continues with cleanups and maintenance work to the
maple tree code. Peng Zhang also does some work on maple tree
- Johannes Weiner has done some cleanup work on the compaction code
- David Hildenbrand has contributed additional selftests for
get_user_pages()
- Thomas Gleixner has contributed some maintenance and optimization
work for the vmalloc code
- Baolin Wang has provided some compaction cleanups,
- SeongJae Park continues maintenance work on the DAMON code
- Huang Ying has done some maintenance on the swap code's usage of
device refcounting
- Christoph Hellwig has some cleanups for the filemap/directio code
- Ryan Roberts provides two patch series which yield some
rationalization of the kernel's access to pte entries - use the
provided APIs rather than open-coding accesses
- Lorenzo Stoakes has some fixes to the interaction between pagecache
and directio access to file mappings
- John Hubbard has a series of fixes to the MM selftesting code
- ZhangPeng continues the folio conversion campaign
- Hugh Dickins has been working on the pagetable handling code, mainly
with a view to reducing the load on the mmap_lock
- Catalin Marinas has reduced the arm64 kmalloc() minimum alignment
from 128 to 8
- Domenico Cerasuolo has improved the zswap reclaim mechanism by
reorganizing the LRU management
- Matthew Wilcox provides some fixups to make gfs2 work better with the
buffer_head code
- Vishal Moola also has done some folio conversion work
- Matthew Wilcox has removed the remnants of the pagevec code - their
functionality is migrated over to struct folio_batch
* tag 'mm-stable-2023-06-24-19-15' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (380 commits)
mm/hugetlb: remove hugetlb_set_page_subpool()
mm: nommu: correct the range of mmap_sem_read_lock in task_mem()
hugetlb: revert use of page_cache_next_miss()
Revert "page cache: fix page_cache_next/prev_miss off by one"
mm/vmscan: fix root proactive reclaim unthrottling unbalanced node
mm: memcg: rename and document global_reclaim()
mm: kill [add|del]_page_to_lru_list()
mm: compaction: convert to use a folio in isolate_migratepages_block()
mm: zswap: fix double invalidate with exclusive loads
mm: remove unnecessary pagevec includes
mm: remove references to pagevec
mm: rename invalidate_mapping_pagevec to mapping_try_invalidate
mm: remove struct pagevec
net: convert sunrpc from pagevec to folio_batch
i915: convert i915_gpu_error to use a folio_batch
pagevec: rename fbatch_count()
mm: remove check_move_unevictable_pages()
drm: convert drm_gem_put_pages() to use a folio_batch
i915: convert shmem_sg_free_table() to use a folio_batch
scatterlist: add sg_set_folio()
...
For historical reasons, unbound workqueues with max concurrency limit of 1
are considered ordered, even though the concurrency limit hasn't been
system-wide for a long time. This creates ambiguity around whether ordered
execution is actually required for correctness, which was actually confusing
for e.g. btrfs (btrfs updates are being routed through the btrfs tree).
There aren't that many users in the tree which use the combination and there
are pending improvements to unbound workqueue affinity handling which will
make inadvertent use of ordered workqueue a bigger loss. This pull request
clarifies the situation for most of them by updating the ones which require
ordered execution to use alloc_ordered_workqueue().
There are some conversions being routed through subsystem-specific trees and
likely a few stragglers. Once they're all converted, workqueue can trigger a
warning on unbound + @max_active==1 usages and eventually drop the implicit
ordered behavior.
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Merge tag 'wq-for-6.5-cleanup-ordered' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull ordered workqueue creation updates from Tejun Heo:
"For historical reasons, unbound workqueues with max concurrency limit
of 1 are considered ordered, even though the concurrency limit hasn't
been system-wide for a long time.
This creates ambiguity around whether ordered execution is actually
required for correctness, which was actually confusing for e.g. btrfs
(btrfs updates are being routed through the btrfs tree).
There aren't that many users in the tree which use the combination and
there are pending improvements to unbound workqueue affinity handling
which will make inadvertent use of ordered workqueue a bigger loss.
This clarifies the situation for most of them by updating the ones
which require ordered execution to use alloc_ordered_workqueue().
There are some conversions being routed through subsystem-specific
trees and likely a few stragglers. Once they're all converted,
workqueue can trigger a warning on unbound + @max_active==1 usages and
eventually drop the implicit ordered behavior"
* tag 'wq-for-6.5-cleanup-ordered' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
rxrpc: Use alloc_ordered_workqueue() to create ordered workqueues
net: qrtr: Use alloc_ordered_workqueue() to create ordered workqueues
net: wwan: t7xx: Use alloc_ordered_workqueue() to create ordered workqueues
dm integrity: Use alloc_ordered_workqueue() to create ordered workqueues
media: amphion: Use alloc_ordered_workqueue() to create ordered workqueues
scsi: NCR5380: Use default @max_active for hostdata->work_q
media: coda: Use alloc_ordered_workqueue() to create ordered workqueues
crypto: octeontx2: Use alloc_ordered_workqueue() to create ordered workqueues
wifi: ath10/11/12k: Use alloc_ordered_workqueue() to create ordered workqueues
wifi: mwifiex: Use default @max_active for workqueues
wifi: iwlwifi: Use default @max_active for trans_pcie->rba.alloc_wq
xen/pvcalls: Use alloc_ordered_workqueue() to create ordered workqueues
virt: acrn: Use alloc_ordered_workqueue() to create ordered workqueues
net: octeontx2: Use alloc_ordered_workqueue() to create ordered workqueues
net: thunderx: Use alloc_ordered_workqueue() to create ordered workqueues
greybus: Use alloc_ordered_workqueue() to create ordered workqueues
powerpc, workqueue: Use alloc_ordered_workqueue() to create ordered workqueues
Convert all instances of direct pte_t* dereferencing to instead use
ptep_get() helper. This means that by default, the accesses change from a
C dereference to a READ_ONCE(). This is technically the correct thing to
do since where pgtables are modified by HW (for access/dirty) they are
volatile and therefore we should always ensure READ_ONCE() semantics.
But more importantly, by always using the helper, it can be overridden by
the architecture to fully encapsulate the contents of the pte. Arch code
is deliberately not converted, as the arch code knows best. It is
intended that arch code (arm64) will override the default with its own
implementation that can (e.g.) hide certain bits from the core code, or
determine young/dirty status by mixing in state from another source.
Conversion was done using Coccinelle:
----
// $ make coccicheck \
// COCCI=ptepget.cocci \
// SPFLAGS="--include-headers" \
// MODE=patch
virtual patch
@ depends on patch @
pte_t *v;
@@
- *v
+ ptep_get(v)
----
Then reviewed and hand-edited to avoid multiple unnecessary calls to
ptep_get(), instead opting to store the result of a single call in a
variable, where it is correct to do so. This aims to negate any cost of
READ_ONCE() and will benefit arch-overrides that may be more complex.
Included is a fix for an issue in an earlier version of this patch that
was pointed out by kernel test robot. The issue arose because config
MMU=n elides definition of the ptep helper functions, including
ptep_get(). HUGETLB_PAGE=n configs still define a simple
huge_ptep_clear_flush() for linking purposes, which dereferences the ptep.
So when both configs are disabled, this caused a build error because
ptep_get() is not defined. Fix by continuing to do a direct dereference
when MMU=n. This is safe because for this config the arch code cannot be
trying to virtualize the ptes because none of the ptep helpers are
defined.
Link: https://lkml.kernel.org/r/20230612151545.3317766-4-ryan.roberts@arm.com
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202305120142.yXsNEo6H-lkp@intel.com/
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Merge tag 'for-linus-6.4-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen fixes from Juergen Gross:
- a double free fix in the Xen pvcalls backend driver
- a fix for a regression causing the MSI related sysfs entries to not
being created in Xen PV guests
- a fix in the Xen blkfront driver for handling insane input data
better
* tag 'for-linus-6.4-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
x86/pci/xen: populate MSI sysfs entries
xen/pvcalls-back: fix double frees with pvcalls_new_active_socket()
xen/blkfront: Only check REQ_FUA for writes
In the pvcalls_new_active_socket() function, most error paths call
pvcalls_back_release_active(fedata->dev, fedata, map) which calls
sock_release() on "sock". The bug is that the caller also frees sock.
Fix this by making every error path in pvcalls_new_active_socket()
release the sock, and don't free it in the caller.
Fixes: 5db4d286a8 ("xen/pvcalls: implement connect command")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/e5f98dc2-0305-491f-a860-71bbd1398a2f@kili.mountain
Signed-off-by: Juergen Gross <jgross@suse.com>
BACKGROUND
==========
When multiple work items are queued to a workqueue, their execution order
doesn't match the queueing order. They may get executed in any order and
simultaneously. When fully serialized execution - one by one in the queueing
order - is needed, an ordered workqueue should be used which can be created
with alloc_ordered_workqueue().
However, alloc_ordered_workqueue() was a later addition. Before it, an
ordered workqueue could be obtained by creating an UNBOUND workqueue with
@max_active==1. This originally was an implementation side-effect which was
broken by 4c16bd327c ("workqueue: restore WQ_UNBOUND/max_active==1 to be
ordered"). Because there were users that depended on the ordered execution,
5c0338c687 ("workqueue: restore WQ_UNBOUND/max_active==1 to be ordered")
made workqueue allocation path to implicitly promote UNBOUND workqueues w/
@max_active==1 to ordered workqueues.
While this has worked okay, overloading the UNBOUND allocation interface
this way creates other issues. It's difficult to tell whether a given
workqueue actually needs to be ordered and users that legitimately want a
min concurrency level wq unexpectedly gets an ordered one instead. With
planned UNBOUND workqueue updates to improve execution locality and more
prevalence of chiplet designs which can benefit from such improvements, this
isn't a state we wanna be in forever.
This patch series audits all callsites that create an UNBOUND workqueue w/
@max_active==1 and converts them to alloc_ordered_workqueue() as necessary.
WHAT TO LOOK FOR
================
The conversions are from
alloc_workqueue(WQ_UNBOUND | flags, 1, args..)
to
alloc_ordered_workqueue(flags, args...)
which don't cause any functional changes. If you know that fully ordered
execution is not ncessary, please let me know. I'll drop the conversion and
instead add a comment noting the fact to reduce confusion while conversion
is in progress.
If you aren't fully sure, it's completely fine to let the conversion
through. The behavior will stay exactly the same and we can always
reconsider later.
As there are follow-up workqueue core changes, I'd really appreciate if the
patch can be routed through the workqueue tree w/ your acks. Thanks.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: xen-devel@lists.xenproject.org
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Merge tag 'for-linus-6.4-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from Juergen Gross:
- some cleanups in the Xen blkback driver
- fix potential sleeps under lock in various Xen drivers
* tag 'for-linus-6.4-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/blkback: move blkif_get_x86_*_req() into blkback.c
xen/blkback: simplify free_persistent_gnts() interface
xen/blkback: remove stale prototype
xen/blkback: fix white space code style issues
xen/pvcalls: don't call bind_evtchn_to_irqhandler() under lock
xen/scsiback: don't call scsiback_free_translation_entry() under lock
xen/pciback: don't call pcistub_device_put() under lock
This pull request goes with only a few sysctl moves from the
kernel/sysctl.c file, the rest of the work has been put towards
deprecating two API calls which incur recursion and prevent us
from simplifying the registration process / saving memory per
move. Most of the changes have been soaking on linux-next since
v6.3-rc3.
I've slowed down the kernel/sysctl.c moves due to Matthew Wilcox's
feedback that we should see if we could *save* memory with these
moves instead of incurring more memory. We currently incur more
memory since when we move a syctl from kernel/sysclt.c out to its
own file we end up having to add a new empty sysctl used to register
it. To achieve saving memory we want to allow syctls to be passed
without requiring the end element being empty, and just have our
registration process rely on ARRAY_SIZE(). Without this, supporting
both styles of sysctls would make the sysctl registration pretty
brittle, hard to read and maintain as can be seen from Meng Tang's
efforts to do just this [0]. Fortunately, in order to use ARRAY_SIZE()
for all sysctl registrations also implies doing the work to deprecate
two API calls which use recursion in order to support sysctl
declarations with subdirectories.
And so during this development cycle quite a bit of effort went into
this deprecation effort. I've annotated the following two APIs are
deprecated and in few kernel releases we should be good to remove them:
* register_sysctl_table()
* register_sysctl_paths()
During this merge window we should be able to deprecate and unexport
register_sysctl_paths(), we can probably do that towards the end
of this merge window.
Deprecating register_sysctl_table() will take a bit more time but
this pull request goes with a few example of how to do this.
As it turns out each of the conversions to move away from either of
these two API calls *also* saves memory. And so long term, all these
changes *will* prove to have saved a bit of memory on boot.
The way I see it then is if remove a user of one deprecated call, it
gives us enough savings to move one kernel/sysctl.c out from the
generic arrays as we end up with about the same amount of bytes.
Since deprecating register_sysctl_table() and register_sysctl_paths()
does not require maintainer coordination except the final unexport
you'll see quite a bit of these changes from other pull requests, I've
just kept the stragglers after rc3.
Most of these changes have been soaking on linux-next since around rc3.
[0] https://lkml.kernel.org/r/ZAD+cpbrqlc5vmry@bombadil.infradead.org
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Merge tag 'sysctl-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux
Pull sysctl updates from Luis Chamberlain:
"This only does a few sysctl moves from the kernel/sysctl.c file, the
rest of the work has been put towards deprecating two API calls which
incur recursion and prevent us from simplifying the registration
process / saving memory per move. Most of the changes have been
soaking on linux-next since v6.3-rc3.
I've slowed down the kernel/sysctl.c moves due to Matthew Wilcox's
feedback that we should see if we could *save* memory with these moves
instead of incurring more memory. We currently incur more memory since
when we move a syctl from kernel/sysclt.c out to its own file we end
up having to add a new empty sysctl used to register it. To achieve
saving memory we want to allow syctls to be passed without requiring
the end element being empty, and just have our registration process
rely on ARRAY_SIZE(). Without this, supporting both styles of sysctls
would make the sysctl registration pretty brittle, hard to read and
maintain as can be seen from Meng Tang's efforts to do just this [0].
Fortunately, in order to use ARRAY_SIZE() for all sysctl registrations
also implies doing the work to deprecate two API calls which use
recursion in order to support sysctl declarations with subdirectories.
And so during this development cycle quite a bit of effort went into
this deprecation effort. I've annotated the following two APIs are
deprecated and in few kernel releases we should be good to remove
them:
- register_sysctl_table()
- register_sysctl_paths()
During this merge window we should be able to deprecate and unexport
register_sysctl_paths(), we can probably do that towards the end of
this merge window.
Deprecating register_sysctl_table() will take a bit more time but this
pull request goes with a few example of how to do this.
As it turns out each of the conversions to move away from either of
these two API calls *also* saves memory. And so long term, all these
changes *will* prove to have saved a bit of memory on boot.
The way I see it then is if remove a user of one deprecated call, it
gives us enough savings to move one kernel/sysctl.c out from the
generic arrays as we end up with about the same amount of bytes.
Since deprecating register_sysctl_table() and register_sysctl_paths()
does not require maintainer coordination except the final unexport
you'll see quite a bit of these changes from other pull requests, I've
just kept the stragglers after rc3"
Link: https://lkml.kernel.org/r/ZAD+cpbrqlc5vmry@bombadil.infradead.org [0]
* tag 'sysctl-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: (29 commits)
fs: fix sysctls.c built
mm: compaction: remove incorrect #ifdef checks
mm: compaction: move compaction sysctl to its own file
mm: memory-failure: Move memory failure sysctls to its own file
arm: simplify two-level sysctl registration for ctl_isa_vars
ia64: simplify one-level sysctl registration for kdump_ctl_table
utsname: simplify one-level sysctl registration for uts_kern_table
ntfs: simplfy one-level sysctl registration for ntfs_sysctls
coda: simplify one-level sysctl registration for coda_table
fs/cachefiles: simplify one-level sysctl registration for cachefiles_sysctls
xfs: simplify two-level sysctl registration for xfs_table
nfs: simplify two-level sysctl registration for nfs_cb_sysctls
nfs: simplify two-level sysctl registration for nfs4_cb_sysctls
lockd: simplify two-level sysctl registration for nlm_sysctls
proc_sysctl: enhance documentation
xen: simplify sysctl registration for balloon
md: simplify sysctl registration
hv: simplify sysctl registration
scsi: simplify sysctl registration with register_sysctl()
csky: simplify alignment sysctl registration
...
Updates to the usual drivers (megaraid_sas, scsi_debug, lpfc, target,
mpi3mr, hisi_sas, arcmsr). The major core change is the
constification of the host templates (which touches everything) along
with other minor fixups and clean ups.
Signed-off-by: James E.J. Bottomley <jejb@linux.ibm.com>
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Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Pull SCSI updates from James Bottomley:
"Updates to the usual drivers (megaraid_sas, scsi_debug, lpfc, target,
mpi3mr, hisi_sas, arcmsr).
The major core change is the constification of the host templates
(which touches everything) along with other minor fixups and clean
ups"
* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (207 commits)
scsi: ufs: mcq: Use pointer arithmetic in ufshcd_send_command()
scsi: ufs: mcq: Annotate ufshcd_inc_sq_tail() appropriately
scsi: cxlflash: s/semahpore/semaphore/
scsi: lpfc: Silence an incorrect device output
scsi: mpi3mr: Use IRQ save variants of spinlock to protect chain frame allocation
scsi: scsi_debug: Fix missing error code in scsi_debug_init()
scsi: hisi_sas: Work around build failure in suspend function
scsi: lpfc: Fix ioremap issues in lpfc_sli4_pci_mem_setup()
scsi: mpt3sas: Fix an issue when driver is being removed
scsi: mpt3sas: Remove HBA BIOS version in the kernel log
scsi: target: core: Fix invalid memory access
scsi: scsi_debug: Drop sdebug_queue
scsi: scsi_debug: Only allow sdebug_max_queue be modified when no shosts
scsi: scsi_debug: Use scsi_host_busy() in delay_store() and ndelay_store()
scsi: scsi_debug: Use blk_mq_tagset_busy_iter() in stop_all_queued()
scsi: scsi_debug: Use blk_mq_tagset_busy_iter() in sdebug_blk_mq_poll()
scsi: scsi_debug: Dynamically allocate sdebug_queued_cmd
scsi: scsi_debug: Use scsi_block_requests() to block queues
scsi: scsi_debug: Protect block_unblock_all_queues() with mutex
scsi: scsi_debug: Change shost list lock to a mutex
...
bind_evtchn_to_irqhandler() shouldn't be called under spinlock, as it
can sleep.
This requires to move the calls of create_active() out of the locked
regions. This is no problem, as the worst which could happen would be
a spurious call of the interrupt handler, causing a spurious wake_up().
Reported-by: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/lkml/Y+JUIl64UDmdkboh@kadam/
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20230403092711.15285-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
scsiback_free_translation_entry() shouldn't be called under spinlock,
as it can sleep.
This requires to split removing a translation entry from the v2p list
from actually calling kref_put() for the entry.
Reported-by: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/lkml/Y+JUIl64UDmdkboh@kadam/
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Link: https://lore.kernel.org/r/20230328084602.20729-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
pcistub_device_put() shouldn't be called under spinlock, as it can
sleep.
For this reason pcistub_device_get_pci_dev() needs to be modified:
instead of always calling pcistub_device_get() just do the call of
pcistub_device_get() only if it is really needed. This removes the
need to call pcistub_device_put().
Reported-by: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/lkml/Y+JUIl64UDmdkboh@kadam/
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Link: https://lore.kernel.org/r/20230328084549.20695-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
register_sysctl_table() is a deprecated compatibility wrapper.
register_sysctl_init() can do the directory creation for you so just
use that.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
In ACPI systems, the OS can direct power management, as opposed to the
firmware. This OS-directed Power Management is called OSPM. Part of
telling the firmware that the OS going to direct power management is
making ACPI "_PDC" (Processor Driver Capabilities) calls. These _PDC
methods must be evaluated for every processor object. If these _PDC
calls are not completed for every processor it can lead to
inconsistency and later failures in things like the CPU frequency
driver.
In a Xen system, the dom0 kernel is responsible for system-wide power
management. The dom0 kernel is in charge of OSPM. However, the
number of CPUs available to dom0 can be different than the number of
CPUs physically present on the system.
This leads to a problem: the dom0 kernel needs to evaluate _PDC for
all the processors, but it can't always see them.
In dom0 kernels, ignore the existing ACPI method for determining if a
processor is physically present because it might not be accurate.
Instead, ask the hypervisor for this information.
Fix this by introducing a custom function to use when running as Xen
dom0 in order to check whether a processor object matches a CPU that's
online. Such checking is done using the existing information fetched
by the Xen pCPU subsystem, extending it to also store the ACPI ID.
This ensures that _PDC method gets evaluated for all physically online
CPUs, regardless of the number of CPUs made available to dom0.
Fixes: 5d554a7bb0 ("ACPI: processor: add internal processor_physically_present()")
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Merge tag 'for-linus-6.3-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen fixes from Juergen Gross:
- cleanup for xen time handling
- enable the VGA console in a Xen PVH dom0
- cleanup in the xenfs driver
* tag 'for-linus-6.3-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen: remove unnecessary (void*) conversions
x86/PVH: obtain VGA console info in Dom0
x86/xen/time: cleanup xen_tsc_safe_clocksource
xen: update arch/x86/include/asm/xen/cpuid.h
Viresh Kumar