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 95A1CC32771 for ; Mon, 26 Sep 2022 16:04:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235497AbiIZQDj (ORCPT ); Mon, 26 Sep 2022 12:03:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44598 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231396AbiIZQCj (ORCPT ); Mon, 26 Sep 2022 12:02:39 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1B706E6F for ; Mon, 26 Sep 2022 07:51:28 -0700 (PDT) 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 ams.source.kernel.org (Postfix) with ESMTPS id C997CB80AC7 for ; Mon, 26 Sep 2022 14:51:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B6D5C433B5; Mon, 26 Sep 2022 14:51:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1664203885; bh=SZA3KzsHt16PF+DaIYBz7Nb49624LswRe+Ox5z2sq34=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=k1LixNiwiplcKqe80TOHWv6ipi93flRcW96VaPramWhh3r0x5c+Mg1kjDhkX81i+T vOUBv99xCffx5QPhrYunu9hX6KVdCmgeG8MalLfO6LKQB96tuweCY7TQzPja+CoPeo 7hBt9v/sfen+SOnAHKyIISA561HLooQQoBkG6VWCLm6YuYdu4u/u+UL/3DSWqhoZfr LdpjDJoWeD/Wr8nGBtiu6GgA7wkgGkovYNaSDrIXu+sKz8ovvBqExt1fyGVVKcYu7D asIo1SgwBOW45ygeQQ8LYHd1XlDyGoC+QKgKxGhdK3HCAb7wh/idCwMQyC/n3k6DhS f3SxdRr+PwycA== Received: from sofa.misterjones.org ([185.219.108.64] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1ocpS7-00Cips-KI; Mon, 26 Sep 2022 15:51:23 +0100 From: Marc Zyngier To: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org Cc: catalin.marinas@arm.com, bgardon@google.com, shuah@kernel.org, andrew.jones@linux.dev, will@kernel.org, dmatlack@google.com, peterx@redhat.com, pbonzini@redhat.com, zhenyzha@redhat.com, shan.gavin@gmail.com, gshan@redhat.com, James Morse , Suzuki K Poulose , Alexandru Elisei , Oliver Upton Subject: [PATCH v2 2/6] KVM: Add KVM_CAP_DIRTY_LOG_RING_ACQ_REL capability and config option Date: Mon, 26 Sep 2022 15:51:16 +0100 Message-Id: <20220926145120.27974-3-maz@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220926145120.27974-1-maz@kernel.org> References: <20220926145120.27974-1-maz@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, catalin.marinas@arm.com, bgardon@google.com, shuah@kernel.org, andrew.jones@linux.dev, will@kernel.org, dmatlack@google.com, peterx@redhat.com, pbonzini@redhat.com, zhenyzha@redhat.com, shan.gavin@gmail.com, gshan@redhat.com, james.morse@arm.com, suzuki.poulose@arm.com, alexandru.elisei@arm.com, oliver.upton@linux.dev 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: kvm@vger.kernel.org In order to differenciate between architectures that require no extra synchronisation when accessing the dirty ring and those who do, add a new capability (KVM_CAP_DIRTY_LOG_RING_ACQ_REL) that identify the latter sort. TSO architectures can obviously advertise both, while relaxed architectures must only advertise the ACQ_REL version. This requires some configuration symbol rejigging, with HAVE_KVM_DIRTY_RING being only indirectly selected by two top-level config symbols: - HAVE_KVM_DIRTY_RING_TSO for strongly ordered architectures (x86) - HAVE_KVM_DIRTY_RING_ACQ_REL for weakly ordered architectures (arm64) Suggested-by: Paolo Bonzini Signed-off-by: Marc Zyngier --- arch/x86/kvm/Kconfig | 2 +- include/uapi/linux/kvm.h | 1 + virt/kvm/Kconfig | 14 ++++++++++++++ virt/kvm/kvm_main.c | 9 ++++++++- 4 files changed, 24 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index e3cbd7706136..876748b236ff 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig @@ -28,7 +28,7 @@ config KVM select HAVE_KVM_IRQCHIP select HAVE_KVM_PFNCACHE select HAVE_KVM_IRQFD - select HAVE_KVM_DIRTY_RING + select HAVE_KVM_DIRTY_RING_TSO select IRQ_BYPASS_MANAGER select HAVE_KVM_IRQ_BYPASS select HAVE_KVM_IRQ_ROUTING diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index eed0315a77a6..0d5d4419139a 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1177,6 +1177,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_VM_DISABLE_NX_HUGE_PAGES 220 #define KVM_CAP_S390_ZPCI_OP 221 #define KVM_CAP_S390_CPU_TOPOLOGY 222 +#define KVM_CAP_DIRTY_LOG_RING_ACQ_REL 223 #ifdef KVM_CAP_IRQ_ROUTING diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig index a8c5c9f06b3c..800f9470e36b 100644 --- a/virt/kvm/Kconfig +++ b/virt/kvm/Kconfig @@ -19,6 +19,20 @@ config HAVE_KVM_IRQ_ROUTING config HAVE_KVM_DIRTY_RING bool +# Only strongly ordered architectures can select this, as it doesn't +# put any explicit constraint on userspace ordering. They can also +# select the _ACQ_REL version. +config HAVE_KVM_DIRTY_RING_TSO + bool + select HAVE_KVM_DIRTY_RING + depends on X86 + +# Weakly ordered architectures can only select this, advertising +# to userspace the additional ordering requirements. +config HAVE_KVM_DIRTY_RING_ACQ_REL + bool + select HAVE_KVM_DIRTY_RING + config HAVE_KVM_EVENTFD bool select EVENTFD diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 584a5bab3af3..5b064dbadaf4 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -4475,7 +4475,13 @@ static long kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg) case KVM_CAP_NR_MEMSLOTS: return KVM_USER_MEM_SLOTS; case KVM_CAP_DIRTY_LOG_RING: -#ifdef CONFIG_HAVE_KVM_DIRTY_RING +#ifdef CONFIG_HAVE_KVM_DIRTY_RING_TSO + return KVM_DIRTY_RING_MAX_ENTRIES * sizeof(struct kvm_dirty_gfn); +#else + return 0; +#endif + case KVM_CAP_DIRTY_LOG_RING_ACQ_REL: +#ifdef CONFIG_HAVE_KVM_DIRTY_RING_ACQ_REL return KVM_DIRTY_RING_MAX_ENTRIES * sizeof(struct kvm_dirty_gfn); #else return 0; @@ -4580,6 +4586,7 @@ static int kvm_vm_ioctl_enable_cap_generic(struct kvm *kvm, return 0; } case KVM_CAP_DIRTY_LOG_RING: + case KVM_CAP_DIRTY_LOG_RING_ACQ_REL: return kvm_vm_ioctl_enable_dirty_log_ring(kvm, cap->args[0]); default: return kvm_vm_ioctl_enable_cap(kvm, cap); -- 2.34.1