Re: [PATCH 0/3] x86/KVM/VMX: Introduce and use try_cmpxchg64()

Paolo Bonzini
2021-01-18T18:42:10Z

On 15/12/20 19:28, Uros Bizjak wrote:
> This patch series introduces try_cmpxchg64() atomic locking function.
>
> try_cmpxchg64() provides the same interface for 64 bit and 32 bit targets,
> emits CMPXCHGQ for 64 bit targets and CMPXCHG8B for 32 bit targets,
> and provides appropriate fallbacks when CMPXCHG8B is unavailable.
>
> try_cmpxchg64() reuses flags from CMPXCHGQ/CMPXCHG8B instructions and
> avoids unneeded CMP for 64 bit targets or XOR/XOR/OR sequence for
> 32 bit targets.
>
> Cc: Will Deacon <will@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Boqun Feng <boqun.feng@gmail.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: "H. Peter Anvin" <hpa@zytor.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>
>
> Uros Bizjak (3):
> asm-generic/atomic: Add try_cmpxchg64() instrumentation
> locking/atomic/x86: Introduce arch_try_cmpxchg64()
> KVM/VMX: Use try_cmpxchg64() in posted_intr.c
>
> arch/x86/include/asm/cmpxchg_32.h | 62 +++++++++++++++++++----
> arch/x86/include/asm/cmpxchg_64.h | 6 +++
> arch/x86/kvm/vmx/posted_intr.c | 9 ++--
> include/asm-generic/atomic-instrumented.h | 46 ++++++++++++++++-
> scripts/atomic/gen-atomic-instrumented.sh | 2 +-
> 5 files changed, 108 insertions(+), 17 deletions(-)
>

Queued, thanks.

Paolo