linux/arch
Eric Farman d47c4c454a KVM: s390: Fix PV check in deliverable_irqs()
The diag 0x44 handler, which handles a directed yield, goes into a
a codepath that does a kvm_for_each_vcpu() and ultimately
deliverable_irqs().  The new check for kvm_s390_pv_cpu_is_protected()
contains an assertion that the vcpu->mutex is held, which isn't going
to be the case in this scenario.

The result is a plethora of these messages if the lock debugging
is enabled, and thus an implication that we have a problem.

  WARNING: CPU: 9 PID: 16167 at arch/s390/kvm/kvm-s390.h:239 deliverable_irqs+0x1c6/0x1d0 [kvm]
  ...snip...
  Call Trace:
   [<000003ff80429bf2>] deliverable_irqs+0x1ca/0x1d0 [kvm]
  ([<000003ff80429b34>] deliverable_irqs+0x10c/0x1d0 [kvm])
   [<000003ff8042ba82>] kvm_s390_vcpu_has_irq+0x2a/0xa8 [kvm]
   [<000003ff804101e2>] kvm_arch_dy_runnable+0x22/0x38 [kvm]
   [<000003ff80410284>] kvm_vcpu_on_spin+0x8c/0x1d0 [kvm]
   [<000003ff80436888>] kvm_s390_handle_diag+0x3b0/0x768 [kvm]
   [<000003ff80425af4>] kvm_handle_sie_intercept+0x1cc/0xcd0 [kvm]
   [<000003ff80422bb0>] __vcpu_run+0x7b8/0xfd0 [kvm]
   [<000003ff80423de6>] kvm_arch_vcpu_ioctl_run+0xee/0x3e0 [kvm]
   [<000003ff8040ccd8>] kvm_vcpu_ioctl+0x2c8/0x8d0 [kvm]
   [<00000001504ced06>] ksys_ioctl+0xae/0xe8
   [<00000001504cedaa>] __s390x_sys_ioctl+0x2a/0x38
   [<0000000150cb9034>] system_call+0xd8/0x2d8
  2 locks held by CPU 2/KVM/16167:
   #0: 00000001951980c0 (&vcpu->mutex){+.+.}, at: kvm_vcpu_ioctl+0x90/0x8d0 [kvm]
   #1: 000000019599c0f0 (&kvm->srcu){....}, at: __vcpu_run+0x4bc/0xfd0 [kvm]
  Last Breaking-Event-Address:
   [<000003ff80429b34>] deliverable_irqs+0x10c/0x1d0 [kvm]
  irq event stamp: 11967
  hardirqs last  enabled at (11975): [<00000001502992f2>] console_unlock+0x4ca/0x650
  hardirqs last disabled at (11982): [<0000000150298ee8>] console_unlock+0xc0/0x650
  softirqs last  enabled at (7940): [<0000000150cba6ca>] __do_softirq+0x422/0x4d8
  softirqs last disabled at (7929): [<00000001501cd688>] do_softirq_own_stack+0x70/0x80

Considering what's being done here, let's fix this by removing the
mutex assertion rather than acquiring the mutex for every other vcpu.

Fixes: 201ae986ea ("KVM: s390: protvirt: Implement interrupt injection")
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Link: https://lore.kernel.org/r/20200415190353.63625-1-farman@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2020-04-20 11:23:45 +02:00
..
alpha mm/special: create generic fallbacks for pte_special() and pte_mkspecial() 2020-04-10 15:36:21 -07:00
arc mm/vma: define a default value for VM_DATA_DEFAULT_FLAGS 2020-04-10 15:36:21 -07:00
arm xen: branch for v5.7-rc2 2020-04-17 10:35:17 -07:00
arm64 arm64: Delete the space separator in __emit_inst 2020-04-15 13:07:12 +01:00
c6x mm/vma: define a default value for VM_DATA_DEFAULT_FLAGS 2020-04-10 15:36:21 -07:00
csky mm/special: create generic fallbacks for pte_special() and pte_mkspecial() 2020-04-10 15:36:21 -07:00
h8300 Kbuild updates for v5.7 (2nd) 2020-04-11 09:46:12 -07:00
hexagon mm/special: create generic fallbacks for pte_special() and pte_mkspecial() 2020-04-10 15:36:21 -07:00
ia64 mm/memory_hotplug: add pgprot_t to mhp_params 2020-04-10 15:36:21 -07:00
m68k m68k: Drop redundant generic-y += hardirq.h 2020-04-13 11:08:52 -07:00
microblaze mm/special: create generic fallbacks for pte_special() and pte_mkspecial() 2020-04-10 15:36:21 -07:00
mips Kbuild updates for v5.7 (2nd) 2020-04-11 09:46:12 -07:00
nds32 mm/special: create generic fallbacks for pte_special() and pte_mkspecial() 2020-04-10 15:36:21 -07:00
nios2 nios2 update for v5.7-rc1 2020-04-11 11:38:44 -07:00
openrisc mm/special: create generic fallbacks for pte_special() and pte_mkspecial() 2020-04-10 15:36:21 -07:00
parisc mm/special: create generic fallbacks for pte_special() and pte_mkspecial() 2020-04-10 15:36:21 -07:00
powerpc mm/memory_hotplug: add pgprot_t to mhp_params 2020-04-10 15:36:21 -07:00
riscv Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-04-16 14:52:29 -07:00
s390 KVM: s390: Fix PV check in deliverable_irqs() 2020-04-20 11:23:45 +02:00
sh Kbuild updates for v5.7 (2nd) 2020-04-11 09:46:12 -07:00
sparc mm/special: create generic fallbacks for pte_special() and pte_mkspecial() 2020-04-10 15:36:21 -07:00
um mm/special: create generic fallbacks for pte_special() and pte_mkspecial() 2020-04-10 15:36:21 -07:00
unicore32 mm/special: create generic fallbacks for pte_special() and pte_mkspecial() 2020-04-10 15:36:21 -07:00
x86 A set of fixes for x86 and objtool: 2020-04-19 11:58:32 -07:00
xtensa Merge branch 'akpm' (patches from Andrew) 2020-04-10 17:57:48 -07:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
Kconfig dma-mapping updates for 5.7 2020-04-04 10:12:47 -07:00