Pull hyper-v fixes from Wei Liu:
- fix oops reporting on Hyper-V
- make objtool happy
* tag 'hyperv-fixes-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
x86/hyperv: Make hv_setup_sched_clock inline
Drivers: hv: vmbus: Only notify Hyper-V for die events that are oops
Pull hyperv updates from Wei Liu:
- A patch series from Andrea to improve vmbus code
- Two clean-up patches from Alexander and Randy
* tag 'hyperv-next-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
hyperv: hyperv.h: drop a duplicated word
tools: hv: change http to https in hv_kvp_daemon.c
Drivers: hv: vmbus: Remove the lock field from the vmbus_channel struct
scsi: storvsc: Introduce the per-storvsc_device spinlock
Drivers: hv: vmbus: Remove unnecessary channel->lock critical sections (sc_list updaters)
Drivers: hv: vmbus: Use channel_mutex in channel_vp_mapping_show()
Drivers: hv: vmbus: Remove unnecessary channel->lock critical sections (sc_list readers)
Drivers: hv: vmbus: Replace cpumask_test_cpu(, cpu_online_mask) with cpu_online()
Drivers: hv: vmbus: Remove the numa_node field from the vmbus_channel struct
Drivers: hv: vmbus: Remove the target_vp field from the vmbus_channel struct
When the kernel panics, one page of kmsg data may be collected and sent to
Hyper-V to aid in diagnosing the failure. The collected kmsg data typically
contains 50 to 100 lines, each of which has a log level prefix that isn't
very useful from a diagnostic standpoint. So tell kmsg_dump_get_buffer()
to not include the log level, enabling more information that *is* useful to
fit in the page.
Requesting in stable kernels, since many kernels running in production are
stable releases.
Cc: stable@vger.kernel.org
Signed-off-by: Joseph Salisbury <joseph.salisbury@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1593210497-114310-1-git-send-email-joseph.salisbury@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
The primitive currently uses channel->lock to protect the loop over
sc_list w.r.t. list additions/deletions but it doesn't protect the
target_cpu(s) loads w.r.t. a concurrent target_cpu_store(): while the
data races on target_cpu are hardly of any concern here, replace the
channel->lock critical section with a channel_mutex critical section
and extend the latter to include the loads of target_cpu; this same
pattern is also used in hv_synic_cleanup().
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20200617164642.37393-6-parri.andrea@gmail.com
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Pull hyper-v updates from Wei Liu:
- a series from Andrea to support channel reassignment
- a series from Vitaly to clean up Vmbus message handling
- a series from Michael to clean up and augment hyperv-tlfs.h
- patches from Andy to clean up GUID usage in Hyper-V code
- a few other misc patches
* tag 'hyperv-next-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (29 commits)
Drivers: hv: vmbus: Resolve more races involving init_vp_index()
Drivers: hv: vmbus: Resolve race between init_vp_index() and CPU hotplug
vmbus: Replace zero-length array with flexible-array
Driver: hv: vmbus: drop a no long applicable comment
hyper-v: Switch to use UUID types directly
hyper-v: Replace open-coded variant of %*phN specifier
hyper-v: Supply GUID pointer to printf() like functions
hyper-v: Use UUID API for exporting the GUID (part 2)
asm-generic/hyperv: Add definitions for Get/SetVpRegister hypercalls
x86/hyperv: Split hyperv-tlfs.h into arch dependent and independent files
x86/hyperv: Remove HV_PROCESSOR_POWER_STATE #defines
KVM: x86: hyperv: Remove duplicate definitions of Reference TSC Page
drivers: hv: remove redundant assignment to pointer primary_channel
scsi: storvsc: Re-init stor_chns when a channel interrupt is re-assigned
Drivers: hv: vmbus: Introduce the CHANNELMSG_MODIFYCHANNEL message type
Drivers: hv: vmbus: Synchronize init_vp_index() vs. CPU hotplug
Drivers: hv: vmbus: Remove the unused HV_LOCALIZED channel affinity logic
PCI: hv: Prepare hv_compose_msi_msg() for the VMBus-channel-interrupt-to-vCPU reassignment functionality
Drivers: hv: vmbus: Use a spin lock for synchronizing channel scheduling vs. channel removal
hv_utils: Always execute the fcopy and vss callbacks in a tasklet
...
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>
Pull Hyper-V fixes from Wei Liu:
- Two patches from Dexuan fixing suspension bugs
- Three cleanup patches from Andy and Michael
* tag 'hyperv-fixes-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
hyper-v: Remove internal types from UAPI header
hyper-v: Use UUID API for exporting the GUID
x86/hyperv: Suspend/resume the VP assist page for hibernation
Drivers: hv: Move AEOI determination to architecture dependent code
Drivers: hv: vmbus: Fix Suspend-to-Idle for Generation-2 VM
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>
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>
