From 4fdc3431e03b9c11803f399f91837fca487029a1 Mon Sep 17 00:00:00 2001 From: Zheyun Shen Date: Thu, 22 May 2025 16:37:28 -0700 Subject: [PATCH] x86/lib: Add WBINVD and WBNOINVD helpers to target multiple CPUs Extract KVM's open-coded calls to do writeback caches on multiple CPUs to common library helpers for both WBINVD and WBNOINVD (KVM will use both). Put the onus on the caller to check for a non-empty mask to simplify the SMP=n implementation, e.g. so that it doesn't need to check that the one and only CPU in the system is present in the mask. [sean: move to lib, add SMP=n helpers, clarify usage] Signed-off-by: Zheyun Shen Signed-off-by: Sean Christopherson Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Tom Lendacky Acked-by: Kai Huang Link: https://lore.kernel.org/r/20250128015345.7929-2-szy0127@sjtu.edu.cn Link: https://lore.kernel.org/20250522233733.3176144-5-seanjc@google.com --- arch/x86/include/asm/smp.h | 12 ++++++++++++ arch/x86/kvm/x86.c | 3 +-- arch/x86/lib/cache-smp.c | 12 ++++++++++++ 3 files changed, 25 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h index e08f1ae254010..22bfebe6776da 100644 --- a/arch/x86/include/asm/smp.h +++ b/arch/x86/include/asm/smp.h @@ -113,7 +113,9 @@ void native_play_dead(void); void play_dead_common(void); void wbinvd_on_cpu(int cpu); void wbinvd_on_all_cpus(void); +void wbinvd_on_cpus_mask(struct cpumask *cpus); void wbnoinvd_on_all_cpus(void); +void wbnoinvd_on_cpus_mask(struct cpumask *cpus); void smp_kick_mwait_play_dead(void); void __noreturn mwait_play_dead(unsigned int eax_hint); @@ -154,11 +156,21 @@ static inline void wbinvd_on_all_cpus(void) wbinvd(); } +static inline void wbinvd_on_cpus_mask(struct cpumask *cpus) +{ + wbinvd(); +} + static inline void wbnoinvd_on_all_cpus(void) { wbnoinvd(); } +static inline void wbnoinvd_on_cpus_mask(struct cpumask *cpus) +{ + wbnoinvd(); +} + static inline struct cpumask *cpu_llc_shared_mask(int cpu) { return (struct cpumask *)cpumask_of(0); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index a9d992d5652fa..5a2160f449e0e 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8289,8 +8289,7 @@ static int kvm_emulate_wbinvd_noskip(struct kvm_vcpu *vcpu) int cpu = get_cpu(); cpumask_set_cpu(cpu, vcpu->arch.wbinvd_dirty_mask); - on_each_cpu_mask(vcpu->arch.wbinvd_dirty_mask, - wbinvd_ipi, NULL, 1); + wbinvd_on_cpus_mask(vcpu->arch.wbinvd_dirty_mask); put_cpu(); cpumask_clear(vcpu->arch.wbinvd_dirty_mask); } else diff --git a/arch/x86/lib/cache-smp.c b/arch/x86/lib/cache-smp.c index 74e0d5ba867da..c5c60d07308c0 100644 --- a/arch/x86/lib/cache-smp.c +++ b/arch/x86/lib/cache-smp.c @@ -20,6 +20,12 @@ void wbinvd_on_all_cpus(void) } EXPORT_SYMBOL(wbinvd_on_all_cpus); +void wbinvd_on_cpus_mask(struct cpumask *cpus) +{ + on_each_cpu_mask(cpus, __wbinvd, NULL, 1); +} +EXPORT_SYMBOL_GPL(wbinvd_on_cpus_mask); + static void __wbnoinvd(void *dummy) { wbnoinvd(); @@ -30,3 +36,9 @@ void wbnoinvd_on_all_cpus(void) on_each_cpu(__wbnoinvd, NULL, 1); } EXPORT_SYMBOL_GPL(wbnoinvd_on_all_cpus); + +void wbnoinvd_on_cpus_mask(struct cpumask *cpus) +{ + on_each_cpu_mask(cpus, __wbnoinvd, NULL, 1); +} +EXPORT_SYMBOL_GPL(wbnoinvd_on_cpus_mask); -- 2.47.2