From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 911CCC636CC for ; Wed, 8 Feb 2023 10:00:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229942AbjBHKAN (ORCPT ); Wed, 8 Feb 2023 05:00:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45618 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229822AbjBHKAM (ORCPT ); Wed, 8 Feb 2023 05:00:12 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 960291EFD3; Wed, 8 Feb 2023 02:00:11 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3AA43615E4; Wed, 8 Feb 2023 10:00:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 99653C433EF; Wed, 8 Feb 2023 10:00:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1675850410; bh=s4vaxrnc1mvUSnF8N75rkyowNIgbPMRpjaPxjxZkNdA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=X6aQJuDLJ8b0xyWlTxlWTqJluGbIRsWyhr0yE99EhnqK64aGHk5SplHb3ADAuxb9I o7DkMUvAeYEwlXRfj1uSn00lrZWZErjXZfs3IyR9hLdwM8mNgae0qDwf7AmUQBPHQp CZYblt4ABUbD2odM8Po7srQVHiRqdWBx0Bgz8TUKR+uWgCxY7qoV+v1SGx9hob3vXa Tb4Zo14DqDmL2RBpsPVwV4KlL8vhxPOdnyf3ZRvQmyeFd2O/vwBu6/eoa672voZI02 IpiG6dFe3aoxTS+WXFA0IbjccXU9LBG8AYQS4mV2enjY1awcs0z4cLIKiPrmViGvDs JgHcm3sag7j3g== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1pPhFG-008cXn-Rw; Wed, 08 Feb 2023 10:00:08 +0000 Date: Wed, 08 Feb 2023 10:00:06 +0000 Message-ID: <86o7q4zdcp.wl-maz@kernel.org> From: Marc Zyngier To: David Matlack Cc: Paolo Bonzini , James Morse , Suzuki K Poulose , Oliver Upton , Zenghui Yu , Huacai Chen , Aleksandar Markovic , Anup Patel , Atish Patra , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, Raghavendra Rao Ananta Subject: Re: [PATCH v2 2/7] KVM: arm64: Use kvm_arch_flush_remote_tlbs() In-Reply-To: <20230126184025.2294823-3-dmatlack@google.com> References: <20230126184025.2294823-1-dmatlack@google.com> <20230126184025.2294823-3-dmatlack@google.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/28.2 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: dmatlack@google.com, pbonzini@redhat.com, james.morse@arm.com, suzuki.poulose@arm.com, oliver.upton@linux.dev, yuzenghui@huawei.com, chenhuacai@kernel.org, aleksandar.qemu.devel@gmail.com, anup@brainfault.org, atishp@atishpatra.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, seanjc@google.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, rananta@google.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On Thu, 26 Jan 2023 18:40:20 +0000, David Matlack wrote: > > Use kvm_arch_flush_remote_tlbs() instead of > CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL. The two mechanisms solve the same > problem, allowing architecture-specific code to provide a non-IPI > implementation of remote TLB flushing. > > Dropping CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL allows KVM to standardize > all architectures on kvm_arch_flush_remote_tlbs() instead of maintaining > two mechanisms. > > Opt to standardize on kvm_arch_flush_remote_tlbs() since it avoids > duplicating the generic TLB stats across architectures that implement > their own remote TLB flush. > > This adds an extra function call to the ARM64 kvm_flush_remote_tlbs() > path, but that is a small cost in comparison to flushing remote TLBs. > > No functional change intended. > > Signed-off-by: David Matlack > --- > arch/arm64/include/asm/kvm_host.h | 3 +++ > arch/arm64/kvm/Kconfig | 1 - > arch/arm64/kvm/mmu.c | 6 +++--- > virt/kvm/Kconfig | 3 --- > virt/kvm/kvm_main.c | 2 -- > 5 files changed, 6 insertions(+), 9 deletions(-) > > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index 113e20fdbb56..062800f1dc54 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -998,6 +998,9 @@ int __init kvm_set_ipa_limit(void); > #define __KVM_HAVE_ARCH_VM_ALLOC > struct kvm *kvm_arch_alloc_vm(void); > > +#define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS > +int kvm_arch_flush_remote_tlbs(struct kvm *kvm); > + > static inline bool kvm_vm_is_protected(struct kvm *kvm) > { > return false; > diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig > index ca6eadeb7d1a..e9ac57098a0b 100644 > --- a/arch/arm64/kvm/Kconfig > +++ b/arch/arm64/kvm/Kconfig > @@ -25,7 +25,6 @@ menuconfig KVM > select MMU_NOTIFIER > select PREEMPT_NOTIFIERS > select HAVE_KVM_CPU_RELAX_INTERCEPT > - select HAVE_KVM_ARCH_TLB_FLUSH_ALL > select KVM_MMIO > select KVM_GENERIC_DIRTYLOG_READ_PROTECT > select KVM_XFER_TO_GUEST_WORK > diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c > index 01352f5838a0..8840f65e0e40 100644 > --- a/arch/arm64/kvm/mmu.c > +++ b/arch/arm64/kvm/mmu.c > @@ -80,15 +80,15 @@ static bool memslot_is_logging(struct kvm_memory_slot *memslot) > } > > /** > - * kvm_flush_remote_tlbs() - flush all VM TLB entries for v7/8 > + * kvm_arch_flush_remote_tlbs() - flush all VM TLB entries for v7/8 > * @kvm: pointer to kvm structure. > * > * Interface to HYP function to flush all VM TLB entries > */ > -void kvm_flush_remote_tlbs(struct kvm *kvm) > +int kvm_arch_flush_remote_tlbs(struct kvm *kvm) > { > - ++kvm->stat.generic.remote_tlb_flush_requests; > kvm_call_hyp(__kvm_tlb_flush_vmid, &kvm->arch.mmu); > + return 0; > } > > static bool kvm_is_device_pfn(unsigned long pfn) > diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig > index b74916de5183..484d0873061c 100644 > --- a/virt/kvm/Kconfig > +++ b/virt/kvm/Kconfig > @@ -62,9 +62,6 @@ config HAVE_KVM_CPU_RELAX_INTERCEPT > config KVM_VFIO > bool > > -config HAVE_KVM_ARCH_TLB_FLUSH_ALL > - bool > - > config HAVE_KVM_INVALID_WAKEUPS > bool > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 277507463678..fefd3e3c8fe1 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -347,7 +347,6 @@ bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req) > } > EXPORT_SYMBOL_GPL(kvm_make_all_cpus_request); > > -#ifndef CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL > void kvm_flush_remote_tlbs(struct kvm *kvm) > { > ++kvm->stat.generic.remote_tlb_flush_requests; > @@ -368,7 +367,6 @@ void kvm_flush_remote_tlbs(struct kvm *kvm) > ++kvm->stat.generic.remote_tlb_flush; > } For context, we currently have this: if (!kvm_arch_flush_remote_tlb(kvm) || kvm_make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH)) ++kvm->stat.generic.remote_tlb_flush; Is there any reason why we shouldn't move the KVM_REQ_TLB_FLUSH call into the arch-specific helpers? This is architecture specific, even if the majority of the supported architecture cannot do broadcast invalidation like arm64 does. Thanks, M. -- Without deviation from the norm, progress is not possible.