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 692B6C54E94 for ; Tue, 24 Jan 2023 17:26:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233149AbjAXR0i (ORCPT ); Tue, 24 Jan 2023 12:26:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58918 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232166AbjAXR0h (ORCPT ); Tue, 24 Jan 2023 12:26:37 -0500 X-Greylist: delayed 552 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Tue, 24 Jan 2023 09:26:33 PST Received: from out-72.mta0.migadu.com (out-72.mta0.migadu.com [91.218.175.72]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BACFC4AA6E for ; Tue, 24 Jan 2023 09:26:33 -0800 (PST) Date: Tue, 24 Jan 2023 17:17:12 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1674580638; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=KIEASO5qPs55lTPiWLXCZgFc1uWbFeBJE6bZJxvRUc0=; b=pHL003ov1XfnmIFlNayK1LaKatLGFuHSsS50iKWIk9FUm7eZ3+Hh4zvnZo0gD4kA+Ikrly jgan9mv2Uos5m1WyH5cRwTLVHswqpM8wNprQ67Jyt6Jw1juH3/vuLsyhSdzSnnXDYt8ofY ju2OUJ7yTEO4EIJpNHPVHxdHb1S591c= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: David Matlack Cc: Paolo Bonzini , Marc Zyngier , James Morse , Suzuki K Poulose , 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 2/7] KVM: arm64: Use kvm_arch_flush_remote_tlbs() Message-ID: References: <20230119173559.2517103-1-dmatlack@google.com> <20230119173559.2517103-3-dmatlack@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230119173559.2517103-3-dmatlack@google.com> X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Hi David, On Thu, Jan 19, 2023 at 09:35:54AM -0800, 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 (I assume) that is a small cost in comparison to flushing > remote TLBs. A fair assumption indeed. The real pile up occurs on the DSB subsequent to the TLBI. > 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/kvm_main.c | 2 -- > 4 files changed, 6 insertions(+), 6 deletions(-) I think you're missing the diff that actually drops the Kconfig opton from virt/kvm/Kconfig. -- Thanks, Oliver