kernel.git/drivers/hv/channel.c, branch linux-5.9.y

Drivers: hv: vmbus: Remove the lock field from the vmbus_channel struct

2020-06-20T09:16:19Z

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) Link: https://lore.kernel.org/r/20200617164642.37393-9-parri.andrea@gmail.com Reviewed-by: Michael Kelley Signed-off-by: Wei Liu

Drivers: hv: vmbus: Remove the target_vp field from the vmbus_channel struct

2020-06-19T15:38:10Z

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 Signed-off-by: Andrea Parri (Microsoft) Link: https://lore.kernel.org/r/20200617164642.37393-2-parri.andrea@gmail.com Reviewed-by: Michael Kelley Signed-off-by: Wei Liu

Drivers: hv: vmbus: Introduce the CHANNELMSG_MODIFYCHANNEL message type

2020-04-23T13:17:12Z

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 Signed-off-by: Andrea Parri (Microsoft) Link: https://lore.kernel.org/r/20200406001514.19876-11-parri.andrea@gmail.com Reviewed-by: Michael Kelley [ wei: fix conflict in channel_mgmt.c ] Signed-off-by: Wei Liu

Drivers: hv: vmbus: Use a spin lock for synchronizing channel scheduling vs. channel removal

2020-04-23T13:17:12Z

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 Signed-off-by: Andrea Parri (Microsoft) Link: https://lore.kernel.org/r/20200406001514.19876-7-parri.andrea@gmail.com Reviewed-by: Michael Kelley Signed-off-by: Wei Liu

hv_netvsc: Disable NAPI before closing the VMBus channel

2020-04-23T13:17:11Z

vmbus_chan_sched() might call the netvsc driver callback function that ends up scheduling NAPI work. This "work" can access the channel ring buffer, so we must ensure that any such work is completed and that the ring buffer is no longer being accessed before freeing the ring buffer data structure in the channel closure path. To this end, disable NAPI before calling vmbus_close() in netvsc_device_remove(). Suggested-by: Michael Kelley Signed-off-by: Andrea Parri (Microsoft) Acked-by: Stephen Hemminger Cc: "David S. Miller" Cc: Link: https://lore.kernel.org/r/20200406001514.19876-5-parri.andrea@gmail.com Reviewed-by: Michael Kelley Signed-off-by: Wei Liu

Drivers: hv: vmbus: Fix virt_to_hvpfn() for X86_PAE

2019-08-20T16:49:57Z

In the case of X86_PAE, unsigned long is u32, but the physical address type should be u64. Due to the bug here, the netvsc driver can not load successfully, and sometimes the VM can panic due to memory corruption (the hypervisor writes data to the wrong location). Fixes: 6ba34171bcbd ("Drivers: hv: vmbus: Remove use of slow_virt_to_phys()") Cc: stable@vger.kernel.org Cc: Michael Kelley Reported-and-tested-by: Juliana Rodrigueiro Signed-off-by: Dexuan Cui Reviewed-by: Michael Kelley Signed-off-by: Sasha Levin

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 320

2019-06-05T15:37:05Z

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 Reviewed-by: Allison Randal Reviewed-by: Kate Stewart Reviewed-by: Alexios Zavras Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190530000435.254582722@linutronix.de Signed-off-by: Greg Kroah-Hartman

vmbus: Switch to use new generic UUID API

2019-02-15T01:45:23Z

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" Cc: Haiyang Zhang Cc: Stephen Hemminger Cc: devel@linuxdriverproject.org Signed-off-by: Andy Shevchenko Reviewed-by: Michael Kelley Reviewed-by: Christoph Hellwig Signed-off-by: Sasha Levin

vmbus: fix subchannel removal

2019-01-10T00:20:31Z

The changes to split ring allocation from open/close, broke the cleanup of subchannels. This resulted in problems using uio on network devices because the subchannel was left behind when the network device was unbound. The cause was in the disconnect logic which used list splice to move the subchannel list into a local variable. This won't work because the subchannel list is needed later during the process of the rescind messages (relid2channel). The fix is to just leave the subchannel list in place which is what the original code did. The list is cleaned up later when the host rescind is processed. Without the fix, we have a lot of "hang" issues in netvsc when we try to change the NIC's MTU, set the number of channels, etc. Fixes: ae6935ed7d42 ("vmbus: split ring buffer allocation from open") Cc: stable@vger.kernel.org Signed-off-by: Stephen Hemminger Signed-off-by: Dexuan Cui Signed-off-by: Sasha Levin

Merge 4.20-rc5 into char-misc-next

2018-12-03T06:56:15Z

We need the fixes in here as well. Signed-off-by: Greg Kroah-Hartman