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AJvYcCUDMbTxWu7/mRi5WvS95lR6BxK6ucb9rVvPPyvNTW+uSm17tLYtTres5CpPWOEhqNrl7DU=@vger.kernel.org X-Gm-Message-State: AOJu0YwkH27Bs5TtjA1Wb+3WN0UvsVzc5zQPGQCVFrUwYBaCG+nDZgFu LduT3GBgBZy/Bmwq0J7Txq+F1puPhcNuPvw4PjVtrhMAphI+ppaiF0AG8CUxrrO1NQUr8KzshA+ 94yujRzyRd5X78b14oXNBgUQIbgqQBQ== X-Google-Smtp-Source: AGHT+IHgu+KhlTRU78S3aLawb2EPbz3Nu1d/FQrvmlitnbGv/+v+zOiD3oO/O3xRTVmCngaigziMdprykGf5qEn+FtDZ X-Received: from iobjh3.prod.google.com ([2002:a05:6602:7183:b0:852:28bf:8778]) (user=kevinloughlin job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6602:2b85:b0:842:ef83:d3b2 with SMTP id ca18e2360f4ac-85427e0d83dmr1376167039f.12.1738368187440; Fri, 31 Jan 2025 16:03:07 -0800 (PST) Date: Sat, 1 Feb 2025 00:02:58 +0000 In-Reply-To: <20250201000259.3289143-1-kevinloughlin@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250123002422.1632517-1-kevinloughlin@google.com> <20250201000259.3289143-1-kevinloughlin@google.com> X-Mailer: git-send-email 2.48.1.362.g079036d154-goog Message-ID: <20250201000259.3289143-2-kevinloughlin@google.com> Subject: [PATCH v6 1/2] x86, lib: Add WBNOINVD helper functions From: Kevin Loughlin To: linux-kernel@vger.kernel.org Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, seanjc@google.com, pbonzini@redhat.com, kevinloughlin@google.com, kirill.shutemov@linux.intel.com, kai.huang@intel.com, ubizjak@gmail.com, jgross@suse.com, kvm@vger.kernel.org, thomas.lendacky@amd.com, pgonda@google.com, sidtelang@google.com, mizhang@google.com, rientjes@google.com, manalinandan@google.com, szy0127@sjtu.edu.cn In line with WBINVD usage, add WBONINVD helper functions. For the wbnoinvd() helper, fall back to WBINVD if via alternative() if X86_FEATURE_WBNOINVD is not present. alternative() ensures compatibility with early boot code if needed. Signed-off-by: Kevin Loughlin --- arch/x86/include/asm/smp.h | 7 +++++++ arch/x86/include/asm/special_insns.h | 19 ++++++++++++++++++- arch/x86/lib/cache-smp.c | 12 ++++++++++++ 3 files changed, 37 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h index ca073f40698f..ecf93a243b83 100644 --- a/arch/x86/include/asm/smp.h +++ b/arch/x86/include/asm/smp.h @@ -112,6 +112,7 @@ void native_play_dead(void); void play_dead_common(void); void wbinvd_on_cpu(int cpu); int wbinvd_on_all_cpus(void); +int wbnoinvd_on_all_cpus(void); void smp_kick_mwait_play_dead(void); @@ -160,6 +161,12 @@ static inline int wbinvd_on_all_cpus(void) return 0; } +static inline int wbnoinvd_on_all_cpus(void) +{ + wbnoinvd(); + return 0; +} + static inline struct cpumask *cpu_llc_shared_mask(int cpu) { return (struct cpumask *)cpumask_of(0); diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h index 03e7c2d49559..86a903742139 100644 --- a/arch/x86/include/asm/special_insns.h +++ b/arch/x86/include/asm/special_insns.h @@ -117,7 +117,24 @@ static inline void wrpkru(u32 pkru) static __always_inline void wbinvd(void) { - asm volatile("wbinvd": : :"memory"); + asm volatile("wbinvd" : : : "memory"); +} + +/* Instruction encoding provided for binutils backwards compatibility. */ +#define WBNOINVD ".byte 0xf3,0x0f,0x09" + +/* + * Cheaper version of wbinvd(). Call when caches + * need to be written back but not invalidated. + */ +static __always_inline void wbnoinvd(void) +{ + /* + * If WBNOINVD is unavailable, fall back to the compatible but + * more destructive WBINVD (which still writes the caches back + * but also invalidates them). + */ + alternative("wbinvd", WBNOINVD, X86_FEATURE_WBNOINVD); } static inline unsigned long __read_cr4(void) diff --git a/arch/x86/lib/cache-smp.c b/arch/x86/lib/cache-smp.c index 7af743bd3b13..7ac5cca53031 100644 --- a/arch/x86/lib/cache-smp.c +++ b/arch/x86/lib/cache-smp.c @@ -20,3 +20,15 @@ int wbinvd_on_all_cpus(void) return 0; } EXPORT_SYMBOL(wbinvd_on_all_cpus); + +static void __wbnoinvd(void *dummy) +{ + wbnoinvd(); +} + +int wbnoinvd_on_all_cpus(void) +{ + on_each_cpu(__wbnoinvd, NULL, 1); + return 0; +} +EXPORT_SYMBOL(wbnoinvd_on_all_cpus);