Only the VSCs or ICs that have been hardened and that are critical for
the successful adoption of Confidential VMs should be allowed if the
guest is running isolated. This change reduces the footprint of the
code that will be exercised by Confidential VMs and hence the exposure
to bugs and vulnerabilities.
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210201144814.2701-3-parri.andrea@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
An erroneous or malicious host could send multiple rescind messages for
a same channel. In vmbus_onoffer_rescind(), the guest maps the channel
ID to obtain a pointer to the channel object and it eventually releases
such object and associated data. The host could time rescind messages
and lead to an use-after-free. Add a new flag to the channel structure
to make sure that only one instance of vmbus_onoffer_rescind() can get
the reference to the channel object.
Reported-by: Juan Vazquez <juvazq@microsoft.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20201209070827.29335-6-parri.andrea@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
When channel->device_obj is non-NULL, vmbus_onoffer_rescind() could
invoke put_device(), that will eventually release the device and free
the channel object (cf. vmbus_device_release()). However, a pointer
to the object is dereferenced again later to load the primary_channel.
The use-after-free can be avoided by noticing that this load/check is
redundant if device_obj is non-NULL: primary_channel must be NULL if
device_obj is non-NULL, cf. vmbus_add_channel_work().
Fixes: 54a66265d6 ("Drivers: hv: vmbus: Fix rescind handling")
Reported-by: Juan Vazquez <juvazq@microsoft.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20201209070827.29335-5-parri.andrea@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
For additional robustness in the face of Hyper-V errors or malicious
behavior, validate all values that originate from packets that Hyper-V
has sent to the guest in the host-to-guest ring buffer. Ensure that
invalid values cannot cause indexing off the end of the icversion_data
array in vmbus_prep_negotiate_resp().
Signed-off-by: Andres Beltran <lkmlabelt@gmail.com>
Co-developed-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20201109100704.9152-1-parri.andrea@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
-----BEGIN PGP SIGNATURE-----
iQFHBAABCAAxFiEEIbPD0id6easf0xsudhRwX5BBoF4FAl9grKITHHdlaS5saXVA
a2VybmVsLm9yZwAKCRB2FHBfkEGgXu7gB/4+uML5b8rd06pJ3+NC53Mh5ooePvL5
CdZsLJP+reK8WeG4s3sXSs4kgzwZQcDFEC6k4STvM7B6fOEhvpi2Y7kuhayy75X4
6mZ7qoAnVvy83RZxAxDdgr0PuPRpL8m3cq1C+2hgOe2JaShhLVOC35IZqcBFKxrL
pp6blm7BFC2ST93JKQ3rLT0dhuT2CyLVkXheXbUK+36UnR1OxmgZLVp3PuPXVjdm
1zEkSjWCPAV/I78U7GOoLFx+sUgJwuG+owRQ1o8ZldMO/yj2gfCzfsSDivnjgB10
Q8ihUYZS2jBxg3L5y1pSYwgkOE/Q0iBRG91PueSq0c06mSuKp8COI0xG
=VCYI
-----END PGP SIGNATURE-----
Merge tag 'hyperv-fixes-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull hyperv fixes from Wei Liu:
"Two patches from Michael and Dexuan to fix vmbus hanging issues"
* tag 'hyperv-fixes-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
Drivers: hv: vmbus: Add timeout to vmbus_wait_for_unload
Drivers: hv: vmbus: hibernation: do not hang forever in vmbus_bus_resume()
vmbus_wait_for_unload() looks for a CHANNELMSG_UNLOAD_RESPONSE message
coming from Hyper-V. But if the message isn't found for some reason,
the panic path gets hung forever. Add a timeout of 10 seconds to prevent
this.
Fixes: 415719160d ("Drivers: hv: vmbus: avoid scheduling in interrupt context in vmbus_initiate_unload()")
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/1600026449-23651-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
The spinlock is (now) *not used to protect test-and-set accesses
to attributes of the structure or sc_list operations.
There is, AFAICT, a distinct lack of {WRITE,READ}_ONCE()s in the
handling of channel->state, but the changes below do not seem to
make things "worse". ;-)
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20200617164642.37393-9-parri.andrea@gmail.com
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
None of the readers/updaters of sc_list rely on channel->lock for
synchronization.
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20200617164642.37393-7-parri.andrea@gmail.com
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
The field is read only in numa_node_show() and it is already stored twice
(after a call to cpu_to_node()) in target_cpu_store() and init_vp_index();
there is no need to "cache" its value in the channel data structure.
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20200617164642.37393-3-parri.andrea@gmail.com
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
The field is read only in __vmbus_open() and it is already stored twice
(after a call to hv_cpu_number_to_vp_number()) in target_cpu_store() and
init_vp_index(); there is no need to "cache" its value in the channel
data structure.
Suggested-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20200617164642.37393-2-parri.andrea@gmail.com
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
init_vp_index() uses the (per-node) hv_numa_map[] masks to record the
CPUs allocated for channel interrupts at a given time, and distribute
the performance-critical channels across the available CPUs: in part.,
the mask of "candidate" target CPUs in a given NUMA node, for a newly
offered channel, is determined by XOR-ing the node's CPU mask and the
node's hv_numa_map. This operation/mechanism assumes that no offline
CPUs is set in the hv_numa_map mask, an assumption that does not hold
since such mask is currently not updated when a channel is removed or
assigned to a different CPU.
To address the issues described above, this adds hooks in the channel
removal path (hv_process_channel_removal()) and in target_cpu_store()
in order to clear, resp. to update, the hv_numa_map[] masks as needed.
This also adds a (missed) update of the masks in init_vp_index() (cf.,
e.g., the memory-allocation failure path in this function).
Like in the case of init_vp_index(), such hooks require to determine
if the given channel is performance critical. init_vp_index() does
this by parsing the channel's offer, it can not rely on the device
data structure (device_obj) to retrieve such information because the
device data structure has not been allocated/linked with the channel
by the time that init_vp_index() executes. A similar situation may
hold in hv_is_alloced_cpu() (defined below); the adopted approach is
to "cache" the device type of the channel, as computed by parsing the
channel's offer, in the channel structure itself.
Fixes: 7527810573 ("Drivers: hv: vmbus: Introduce the CHANNELMSG_MODIFYCHANNEL message type")
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20200522171901.204127-3-parri.andrea@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
vmbus_process_offer() does two things (among others):
1) first, it sets the channel's target CPU with cpu_hotplug_lock;
2) it then adds the channel to the channel list(s) with channel_mutex.
Since cpu_hotplug_lock is released before (2), the channel's target CPU
(as designated in (1)) can be deemed "free" by hv_synic_cleanup() and go
offline before the channel is added to the list.
Fix the race condition by "extending" the cpu_hotplug_lock critical
section to include (2) (and (1)), nesting the channel_mutex critical
section within the cpu_hotplug_lock critical section as done elsewhere
(hv_synic_cleanup(), target_cpu_store()) in the hyperv drivers code.
Move even further by extending the channel_mutex critical section to
include (1) (and (2)): this change allows to remove (the now redundant)
bind_channel_to_cpu_lock, and generally simplifies the handling of the
target CPUs (that are now always modified with channel_mutex held).
Fixes: d570aec0f2 ("Drivers: hv: vmbus: Synchronize init_vp_index() vs. CPU hotplug")
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20200522171901.204127-2-parri.andrea@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
The pointer primary_channel is being assigned with a value that is never
used. The assignment is redundant and can be removed. Move the
definition of primary_channel to a narrower scope.
Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20200414152343.243166-1-colin.king@canonical.com
[ wei: move primary_channel and update commit message ]
Signed-off-by: Wei Liu <wei.liu@kernel.org>
VMBus version 4.1 and later support the CHANNELMSG_MODIFYCHANNEL(22)
message type which can be used to request Hyper-V to change the vCPU
that a channel will interrupt.
Introduce the CHANNELMSG_MODIFYCHANNEL message type, and define the
vmbus_send_modifychannel() function to send CHANNELMSG_MODIFYCHANNEL
requests to the host via a hypercall. The function is then used to
define a sysfs "store" operation, which allows to change the (v)CPU
the channel will interrupt by using the sysfs interface. The feature
can be used for load balancing or other purposes.
One interesting catch here is that Hyper-V can *not* currently ACK
CHANNELMSG_MODIFYCHANNEL messages with the promise that (after the ACK
is sent) the channel won't send any more interrupts to the "old" CPU.
The peculiarity of the CHANNELMSG_MODIFYCHANNEL messages is problematic
if the user want to take a CPU offline, since we don't want to take a
CPU offline (and, potentially, "lose" channel interrupts on such CPU)
if the host is still processing a CHANNELMSG_MODIFYCHANNEL message
associated to that CPU.
It is worth mentioning, however, that we have been unable to observe
the above mentioned "race": in all our tests, CHANNELMSG_MODIFYCHANNEL
requests appeared *as if* they were processed synchronously by the host.
Suggested-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20200406001514.19876-11-parri.andrea@gmail.com
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
[ wei: fix conflict in channel_mgmt.c ]
Signed-off-by: Wei Liu <wei.liu@kernel.org>
init_vp_index() may access the cpu_online_mask mask via its calls of
cpumask_of_node(). Make sure to protect these accesses with a
cpus_read_lock() critical section.
Also, remove some (hardcoded) instances of CPU(0) from init_vp_index()
and replace them with VMBUS_CONNECT_CPU. The connect CPU can not go
offline, since Hyper-V does not provide a way to change it.
Finally, order the accesses of target_cpu from init_vp_index() and
hv_synic_cleanup() by relying on the channel_mutex; this is achieved
by moving the call of init_vp_index() into vmbus_process_offer().
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20200406001514.19876-10-parri.andrea@gmail.com
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
The logic is unused since commit 509879bdb3 ("Drivers: hv: Introduce
a policy for controlling channel affinity").
This logic assumes that a channel target_cpu doesn't change during the
lifetime of a channel, but this assumption is incompatible with the new
functionality that allows changing the vCPU a channel will interrupt.
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20200406001514.19876-9-parri.andrea@gmail.com
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Since vmbus_chan_sched() dereferences the ring buffer pointer, we have
to make sure that the ring buffer data structures don't get freed while
such dereferencing is happening. Current code does this by sending an
IPI to the CPU that is allowed to access that ring buffer from interrupt
level, cf., vmbus_reset_channel_cb(). But with the new functionality
to allow changing the CPU that a channel will interrupt, we can't be
sure what CPU will be running the vmbus_chan_sched() function for a
particular channel, so the current IPI mechanism is infeasible.
Instead synchronize vmbus_chan_sched() and vmbus_reset_channel_cb() by
using the (newly introduced) per-channel spin lock "sched_lock". Move
the test for onchannel_callback being NULL before the "switch" control
statement in vmbus_chan_sched(), in order to not access the ring buffer
if the vmbus_reset_channel_cb() has been completed on the channel.
Suggested-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20200406001514.19876-7-parri.andrea@gmail.com
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
When Hyper-V sends an interrupt to the guest, the guest has to figure
out which channel the interrupt is associated with. Hyper-V sets a bit
in a memory page that is shared with the guest, indicating a particular
"relid" that the interrupt is associated with. The current Linux code
then uses a set of per-CPU linked lists to map a given "relid" to a
pointer to a channel structure.
This design introduces a synchronization problem if the CPU that Hyper-V
will interrupt for a certain channel is changed. If the interrupt comes
on the "old CPU" and the channel was already moved to the per-CPU list
of the "new CPU", then the relid -> channel mapping will fail and the
interrupt is dropped. Similarly, if the interrupt comes on the new CPU
but the channel was not moved to the per-CPU list of the new CPU, then
the mapping will fail and the interrupt is dropped.
Relids are integers ranging from 0 to 2047. The mapping from relids to
channel structures can be done by setting up an array with 2048 entries,
each entry being a pointer to a channel structure (hence total size ~16K
bytes, which is not a problem). The array is global, so there are no
per-CPU linked lists to update. The array can be searched and updated
by loading from/storing to the array at the specified index. With no
per-CPU data structures, the above mentioned synchronization problem is
avoided and the relid2channel() function gets simpler.
Suggested-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20200406001514.19876-4-parri.andrea@gmail.com
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
The offer and rescind works are currently scheduled on the so called
"connect CPU". However, this is not really needed: we can synchronize
the works by relying on the usage of the offer_in_progress counter and
of the channel_mutex mutex. This synchronization is already in place.
So, remove this unnecessary "bind to the connect CPU" constraint and
update the inline comments accordingly.
Suggested-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20200406001514.19876-3-parri.andrea@gmail.com
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
VMBus message handlers (channel_message_table) receive a pointer to
'struct vmbus_channel_message_header' and cast it to a structure of their
choice, which is sometimes longer than the header. We, however, don't check
that the message is long enough so in case hypervisor screws up we'll be
accessing memory beyond what was allocated for temporary buffer.
Previously, we used to always allocate and copy 256 bytes from message page
to temporary buffer but this is hardly better: in case the message is
shorter than we expect we'll be trying to consume garbage as some real
data and no memory guarding technique will be able to identify an issue.
Introduce 'min_payload_len' to 'struct vmbus_channel_message_table_entry'
and check against it in vmbus_on_msg_dpc(). Note, we can't require the
exact length as new hypervisor versions may add extra fields to messages,
we only check that the message is not shorter than we expect.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20200406104326.45361-1-vkuznets@redhat.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
vmbus_onmessage() doesn't need the header of the message, it only
uses it to get to the payload, we can pass the pointer to the
payload directly.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20200406104154.45010-4-vkuznets@redhat.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
When kdump is not configured, a Hyper-V VM might still respond to
network traffic after a kernel panic when kernel parameter panic=0.
The panic CPU goes into an infinite loop with interrupts enabled,
and the VMbus driver interrupt handler still works because the
VMbus connection is unloaded only in the kdump path. The network
responses make the other end of the connection think the VM is
still functional even though it has panic'ed, which could affect any
failover actions that should be taken.
Fix this by unloading the VMbus connection during the panic process.
vmbus_initiate_unload() could then be called twice (e.g., by
hyperv_panic_event() and hv_crash_handler(), so reset the connection
state in vmbus_initiate_unload() to ensure the unload is done only
once.
Fixes: 81b18bce48 ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during panic")
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20200406155331.2105-2-Tianyu.Lan@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
When a Linux hv_sock app tries to connect to a Service GUID on which no
host app is listening, a recent host (RS3+) sends a
CHANNELMSG_TL_CONNECT_RESULT (23) message to Linux and this triggers such
a warning:
unknown msgtype=23
WARNING: CPU: 2 PID: 0 at drivers/hv/vmbus_drv.c:1031 vmbus_on_msg_dpc
Actually Linux can safely ignore the message because the Linux app's
connect() will time out in 2 seconds: see VSOCK_DEFAULT_CONNECT_TIMEOUT
and vsock_stream_connect(). We don't bother to make use of the message
because: 1) it's only supported on recent hosts; 2) a non-trivial effort
is required to use the message in Linux, but the benefit is small.
So, let's not see the warning by silently ignoring the message.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
When the host re-offers the primary channels upon resume, the host only
guarantees the Instance GUID doesn't change, so vmbus_bus_suspend()
should invalidate channel->offermsg.child_relid and figure out the
number of primary channels that need to be fixed up upon resume.
Upon resume, vmbus_onoffer() finds the old channel structs, and maps
the new offers to the old channels, and fixes up the old structs,
and finally the resume callbacks of the VSC drivers will re-open
the channels.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Before suspend, Linux must make sure all the hv_sock channels have been
properly cleaned up, because a hv_sock connection can not persist across
hibernation, and the user-space app must be properly notified of the
state change of the connection.
Before suspend, Linux also must make sure all the sub-channels have been
destroyed, i.e. the related channel structs of the sub-channels must be
properly removed, otherwise they would cause a conflict when the
sub-channels are recreated upon resume.
Add a counter to track such channels, and vmbus_bus_suspend() should wait
for the counter to drop to zero.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
When the VM resumes, the host re-sends the offers. We should not add the
offers to the global vmbus_connection.chn_list again.
This patch assumes the RELIDs of the channels don't change across
hibernation. Actually this is not always true, especially in the case of
NIC SR-IOV the VF vmbus device's RELID sometimes can change. A later patch
will address this issue by mapping the new offers to the old channels and
fixing up the old channels, if necessary.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms and conditions of the gnu general public license
version 2 as published by the free software foundation this program
is distributed in the hope it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not write to the free
software foundation inc 59 temple place suite 330 boston ma 02111
1307 usa
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 33 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190530000435.254582722@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix a race condition that can result in a ring buffer pointer being set
to null while a "_show" function is reading the ring buffer's data. This
problem was discussed here: https://lkml.org/lkml/2018/10/18/779
To fix the race condition, add a new mutex lock to the
"hv_ring_buffer_info" struct. Add a new function,
"hv_ringbuffer_pre_init()", where a channel's inbound and outbound
ring_buffer_info mutex locks are initialized.
Acquire/release the locks in the "hv_ringbuffer_cleanup()" function,
which is where the ring buffer pointers are set to null.
Acquire/release the locks in the four channel-level "_show" functions
that access ring buffer data. Remove the "const" qualifier from the
"vmbus_channel" parameter and the "rbi" variable of the channel-level
"_show" functions so that the locks can be acquired/released in these
functions.
Acquire/release the locks in hv_ringbuffer_get_debuginfo(). Remove the
"const" qualifier from the "hv_ring_buffer_info" parameter so that the
locks can be acquired/released in this function.
Signed-off-by: Kimberly Brown <kimbrownkd@gmail.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
There are two methods for signaling the host: the monitor page mechanism
and hypercalls. The monitor page mechanism is used by performance
critical channels (storage, networking, etc.) because it provides
improved throughput. However, latency is increased. Monitor pages are
allocated to these channels.
Monitor pages are not allocated to channels that do not use the monitor
page mechanism. Therefore, these channels do not have a valid monitor id
or valid monitor page data. In these cases, some of the "_show"
functions return incorrect data. They return an invalid monitor id and
data that is beyond the bounds of the hv_monitor_page array fields.
The "channel->offermsg.monitor_allocated" value can be used to determine
whether monitor pages have been allocated to a channel.
Add "is_visible()" callback functions for the device-level and
channel-level attribute groups. These functions will hide the monitor
sysfs files when the monitor mechanism is not used.
Remove ".default_attributes" from "vmbus_chan_attrs" and create a
channel-level attribute group. These changes allow the new
"is_visible()" callback function to be applied to the channel-level
attributes.
Call "sysfs_create_group()" in "vmbus_add_channel_kobj()" to create the
channel's sysfs files. Add a new function,
“vmbus_remove_channel_attr_group()”, and call it in "free_channel()" to
remove the channel's sysfs files when the channel is closed.
Signed-off-by: Kimberly Brown <kimbrownkd@gmail.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
There are new types and helpers that are supposed to be used in new code.
As a preparation to get rid of legacy types and API functions do
the conversion here.
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: devel@linuxdriverproject.org
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
vmbus_process_offer() mustn't call channel->sc_creation_callback()
directly for sub-channels, because sc_creation_callback() ->
vmbus_open() may never get the host's response to the
OPEN_CHANNEL message (the host may rescind a channel at any time,
e.g. in the case of hot removing a NIC), and vmbus_onoffer_rescind()
may not wake up the vmbus_open() as it's blocked due to a non-zero
vmbus_connection.offer_in_progress, and finally we have a deadlock.
The above is also true for primary channels, if the related device
drivers use sync probing mode by default.
And, usually the handling of primary channels and sub-channels can
depend on each other, so we should offload them to different
workqueues to avoid possible deadlock, e.g. in sync-probing mode,
NIC1's netvsc_subchan_work() can race with NIC2's netvsc_probe() ->
rtnl_lock(), and causes deadlock: the former gets the rtnl_lock
and waits for all the sub-channels to appear, but the latter
can't get the rtnl_lock and this blocks the handling of sub-channels.
The patch can fix the multiple-NIC deadlock described above for
v3.x kernels (e.g. RHEL 7.x) which don't support async-probing
of devices, and v4.4, v4.9, v4.14 and v4.18 which support async-probing
but don't enable async-probing for Hyper-V drivers (yet).
The patch can also fix the hang issue in sub-channel's handling described
above for all versions of kernels, including v4.19 and v4.20-rc4.
So actually the patch should be applied to all the existing kernels,
not only the kernels that have 8195b1396e.
Fixes: 8195b1396e ("hv_netvsc: fix deadlock on hotplug")
Cc: stable@vger.kernel.org
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit d86adf482b ("scsi: storvsc: Enable multi-queue support") removed
the usage of the API in Jan 2017, and the API is not used since then.
netvsc and storvsc have their own algorithms to determine the outgoing
channel, so this API is useless.
And the API is potentially unsafe, because it reads primary->num_sc without
any lock held. This can be risky considering the RESCIND-OFFER message.
Let's remove the API.
Cc: Long Li <longli@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
A cpumask structure on the stack can cause a warning with
CONFIG_NR_CPUS=8192 (e.g. Ubuntu 16.04 and 18.04 use this):
drivers/hv//channel_mgmt.c: In function ‘init_vp_index’:
drivers/hv//channel_mgmt.c:702:1: warning: the frame size of 1032 bytes
is larger than 1024 bytes [-Wframe-larger-than=]
Nowadays it looks most distros enable CONFIG_CPUMASK_OFFSTACK=y, and
hence we can work around the warning by using cpumask_var_t.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
No functional change.
Added descriptions for some parameters.
Fixed some typos.
Removed some out-of-date comments.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Rather than passing relid and then looking up the channel.
Pass the channel directly, since caller already knows it.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Before setting channel->rescind in vmbus_rescind_cleanup(), we should make
sure the channel callback won't run any more, otherwise a high-level
driver like pci_hyperv, which may be infinitely waiting for the host VSP's
response and notices the channel has been rescinded, can't safely give
up: e.g., in hv_pci_protocol_negotiation() -> wait_for_response(), it's
unsafe to exit from wait_for_response() and proceed with the on-stack
variable "comp_pkt" popped. The issue was originally spotted by
Michael Kelley <mikelley@microsoft.com>.
In vmbus_close_internal(), the patch also minimizes the range protected by
disabling/enabling channel->callback_event: we don't really need that for
the whole function.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Cc: stable@vger.kernel.org
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
I didn't really hit a real bug, but just happened to spot the bug:
we have decreased the counter at the beginning of vmbus_process_offer(),
so we mustn't decrease it again.
Fixes: 6f3d791f30 ("Drivers: hv: vmbus: Fix rescind handling issues")
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: stable@vger.kernel.org
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Stable <stable@vger.kernel.org> # 4.14 and above
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The pci-hyperv driver's channel callback hv_pci_onchannelcallback() is not
really a hot path, so we don't need to mark it as a perf_device, meaning
with this patch all HV_PCIE channels' target_cpu will be CPU0.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: stable@vger.kernel.org
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The comments doesn't match what the current code does, also have a
typo. This patch corrects them.
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The current rescind processing code will not correctly handle
the case where the host immediately rescinds a channel that has
been offerred. In this case, we could be blocked in the open call and
since the channel is rescinded, the host will not respond and we could
be blocked forever in the vmbus open call.i Fix this problem.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add tracepoint to vmbus_on_message() which is called when we start
processing a blocking from work context.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Andrea Parri (Microsoft)
Andres Beltran
Linus Torvalds
Michael Kelley
Colin Ian King
Vitaly Kuznetsov
Tianyu Lan
Dexuan Cui
Thomas Gleixner
Kimberly Brown
Andy Shevchenko
Greg Kroah-Hartman
Stephen Hemminger
Haiyang Zhang
K. Y. Srinivasan