linux.git/arch/powerpc/kvm/timing.c, branch vsnprintf

KVM: PPC: Merge powerpc's debugfs entry content into generic entry

2022-02-02T09:30:26+00:00

At the moment KVM on PPC creates 4 types of entries under the kvm debugfs:
1) "%pid-%fd" per a KVM instance (for all platforms);
2) "vm%pid" (for PPC Book3s HV KVM);
3) "vm%u_vcpu%u_timing" (for PPC Book3e KVM);
4) "kvm-xive-%p" (for XIVE PPC Book3s KVM, the same for XICS);

The problem with this is that multiple VMs per process is not allowed for
2) and 3) which makes it possible for userspace to trigger errors when
creating duplicated debugfs entries.

This merges all these into 1).

This defines kvm_arch_create_kvm_debugfs() similar to
kvm_arch_create_vcpu_debugfs().

This defines 2 hooks in kvmppc_ops that allow specific KVM implementations
add necessary entries, this adds the _e500 suffix to
kvmppc_create_vcpu_debugfs_e500() to make it clear what platform it is for.

This makes use of already existing kvm_arch_create_vcpu_debugfs() on PPC.

This removes no more used debugfs_dir pointers from PPC kvm_arch structs.

This stops removing vcpu entries as once created vcpus stay around
for the entire life of a VM and removed when the KVM instance is closed,
see commit d56f5136b010 ("KVM: let kvm_destroy_vm_debugfs clean up vCPU
debugfs directories").

Suggested-by: Fabiano Rosas 
Signed-off-by: Alexey Kardashevskiy 
Reviewed-by: Cédric Le Goater 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20220111005404.162219-1-aik@ozlabs.ru

powerpc/kvm: no need to check return value of debugfs_create functions

2020-03-04T11:44:25+00:00

When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Because of this cleanup, we get to remove a few fields in struct
kvm_arch that are now unused.

Signed-off-by: Greg Kroah-Hartman 
[mpe: Fix build error in kvm/timing.c, adapt kvmppc_remove_cpu_debugfs()]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20200209105901.1620958-2-gregkh@linuxfoundation.org

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 266

2019-06-05T15:30:28+00:00

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation this program is
  distributed in the hope that 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 51 franklin street fifth floor boston ma 02110
  1301 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 67 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Allison Randal 
Reviewed-by: Richard Fontana 
Reviewed-by: Alexios Zavras 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141333.953658117@linutronix.de
Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Use seq_puts() in kvmppc_exit_timing_show()

2018-01-11T09:36:06+00:00

A headline should be quickly put into a sequence. Thus use the
function "seq_puts" instead of "seq_printf" for this purpose.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring 
Signed-off-by: Paul Mackerras

KVM: PPC: Remove DCR handling

2014-07-28T17:29:15+00:00

DCR handling was only needed for 440 KVM. Since we removed it, we can also
remove handling of DCR accesses.

Signed-off-by: Alexander Graf

KVM: PPC: fix partial application of "exit timing in ticks"

2011-07-12T10:16:28+00:00

When http://www.spinics.net/lists/kvm-ppc/msg02664.html
was applied to produce commit b51e7aa7ed6d8d134d02df78300ab0f91cfff4d2,
the removal of the conversion in add_exit_timing was left out.

Signed-off-by: Stuart Yoder 
Signed-off-by: Scott Wood 
Signed-off-by: Alexander Graf

KVM: PPC: use ticks, not usecs, for exit timing

2011-05-22T12:47:49+00:00

Convert to microseconds when displaying
(with fix from Bharat Bhushan ).

This reduces rounding error with large quantities of short exits.

Signed-off-by: Stuart Yoder 
Signed-off-by: Scott Wood 
Signed-off-by: Alexander Graf

KVM: PPC: Fix issue clearing exit timing counters

2011-05-11T11:57:04+00:00

Following dump is observed on host when clearing the exit timing counters

[root@p1021mds kvm]# echo -n 'c' > vm1200_vcpu0_timing
INFO: task echo:1276 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
echo          D 0ff5bf94     0  1276   1190 0x00000000
Call Trace:
[c2157e40] [c0007908] __switch_to+0x9c/0xc4
[c2157e50] [c040293c] schedule+0x1b4/0x3bc
[c2157e90] [c04032dc] __mutex_lock_slowpath+0x74/0xc0
[c2157ec0] [c00369e4] kvmppc_init_timing_stats+0x20/0xb8
[c2157ed0] [c0036b00] kvmppc_exit_timing_write+0x84/0x98
[c2157ef0] [c00b9f90] vfs_write+0xc0/0x16c
[c2157f10] [c00ba284] sys_write+0x4c/0x90
[c2157f40] [c000e320] ret_from_syscall+0x0/0x3c

        The vcpu->mutex is used by kvm_ioctl_* (KVM_RUN etc) and same was
used when clearing the stats (in kvmppc_init_timing_stats()). What happens
is that when the guest is idle then it held the vcpu->mutx. While the
exiting timing process waits for guest to release the vcpu->mutex and
a hang state is reached.

        Now using seprate lock for exit timing stats.

Signed-off-by: Bharat Bhushan 
Acked-by: Alexander Graf 
Signed-off-by: Avi Kivity

KVM: PPC: BookE: fix sleep with interrupts disabled

2010-11-05T16:42:28+00:00

It is not legal to call mutex_lock() with interrupts disabled.
This will assert with debug checks enabled.

If there's a real need to disable interrupts here, it could be done
after the mutex is acquired -- but I don't see why it's needed at all.

Signed-off-by: Scott Wood 
Reviewed-by: Christian Ehrhardt 
Signed-off-by: Alexander Graf

powerpc: Remove unnecessary casts of private_data

2010-07-31T04:56:31+00:00

Signed-off-by: Joe Perches 
Signed-off-by: Benjamin Herrenschmidt