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0ac304de73
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Uros Bizjak 0ac304de73 KVM: VMX: Use try_cmpxchg64 in pi_try_set_control 
Use try_cmpxchg64 instead of cmpxchg64 (*ptr, old, new) != old
in pi_try_set_control.  cmpxchg returns success in ZF flag, so this
change saves a compare after cmpxchg (and related move instruction
in front of cmpxchg):

  b9:   88 44 24 60             mov    %al,0x60(%rsp)
  bd:   48 89 c8                mov    %rcx,%rax
  c0:   c6 44 24 62 f2          movb   $0xf2,0x62(%rsp)
  c5:   48 8b 74 24 60          mov    0x60(%rsp),%rsi
  ca:   f0 49 0f b1 34 24       lock cmpxchg %rsi,(%r12)
  d0:   48 39 c1                cmp    %rax,%rcx
  d3:   75 cf                   jne    a4 <vmx_vcpu_pi_load+0xa4>

patched:

  c1:   88 54 24 60             mov    %dl,0x60(%rsp)
  c5:   c6 44 24 62 f2          movb   $0xf2,0x62(%rsp)
  ca:   48 8b 54 24 60          mov    0x60(%rsp),%rdx
  cf:   f0 48 0f b1 13          lock cmpxchg %rdx,(%rbx)
  d4:   75 d5                   jne    ab <vmx_vcpu_pi_load+0xab>

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wanpeng Li <wanpengli@tencent.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Joerg Roedel <joro@8bytes.org>
Reported-by: kernel test robot <lkp@intel.com>
Message-Id: <20220520143737.62513-1-ubizjak@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-15 08:11:24 -04:00
..
alpha Cleanups (and one fix) around struct mount handling. 2022-06-04 19:00:05 -07:00
arc This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
arm This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
arm64 KVM: arm64: Drop stale comment 2022-06-09 13:24:02 +01:00
csky This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
hexagon fork: Generalize PF_IO_WORKER handling 2022-05-07 09:01:59 -05:00
ia64 Bitmap patches for 5.19-rc1 2022-06-04 14:04:27 -07:00
loongarch LoongArch: Add Loongson-3 default config file 2022-06-03 20:09:29 +08:00
m68k This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
microblaze This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
mips This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
nios2 This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
openrisc This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
parisc Kbuild updates for v5.19 (2nd) 2022-06-05 09:06:03 -07:00
powerpc This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
riscv RISC-V: KVM: fix typos in comments 2022-06-09 09:18:15 +05:30
s390 KVM: Move kvm_arch_vcpu_precreate() under kvm->lock 2022-06-08 04:47:28 -04:00
sh This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
sparc This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
um While looking at the ptrace problems with PREEMPT_RT and the problems 2022-06-03 16:13:25 -07:00
x86 KVM: VMX: Use try_cmpxchg64 in pi_try_set_control 2022-06-15 08:11:24 -04:00
xtensa While looking at the ptrace problems with PREEMPT_RT and the problems 2022-06-03 16:13:25 -07:00
.gitignore
Kconfig A set of objtool fixes: 2022-06-05 09:45:27 -07:00