From patchwork Tue Aug 15 09:27:09 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shameerali Kolothum Thodi X-Patchwork-Id: 13353687 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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 67778C001E0 for ; Tue, 15 Aug 2023 09:29:04 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qVqLM-00042q-OD; Tue, 15 Aug 2023 05:28:04 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qVqLK-00042E-QS; Tue, 15 Aug 2023 05:28:02 -0400 Received: from frasgout.his.huawei.com ([185.176.79.56]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qVqLH-0002gA-4j; Tue, 15 Aug 2023 05:28:02 -0400 Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.207]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4RQ5Rl5DGZz6J7Xw; Tue, 15 Aug 2023 17:23:47 +0800 (CST) Received: from A2006125610.china.huawei.com (10.202.227.178) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Tue, 15 Aug 2023 10:27:40 +0100 To: , CC: , , , , , Subject: [PATCH v2] arm/kvm: Enable support for KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE Date: Tue, 15 Aug 2023 10:27:09 +0100 Message-ID: <20230815092709.1290-1-shameerali.kolothum.thodi@huawei.com> X-Mailer: git-send-email 2.12.0.windows.1 MIME-Version: 1.0 X-Originating-IP: [10.202.227.178] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Received-SPF: pass client-ip=185.176.79.56; envelope-from=shameerali.kolothum.thodi@huawei.com; helo=frasgout.his.huawei.com X-Spam_score_int: -11 X-Spam_score: -1.2 X-Spam_bar: - X-Spam_report: (-1.2 / 5.0 requ) AC_FROM_MANY_DOTS=2.999, BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-to: Shameer Kolothum X-Patchwork-Original-From: Shameer Kolothum via From: Shameerali Kolothum Thodi Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Now that we have Eager Page Split support added for ARM in the kernel, enable it in Qemu. This adds, -eager-split-size to -accel sub-options to set the eager page split chunk size. -enable KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE. The chunk size specifies how many pages to break at a time, using a single allocation. Bigger the chunk size, more pages need to be allocated ahead of time. Signed-off-by: Shameer Kolothum --- RFC v1: https://lore.kernel.org/qemu-devel/20230725150002.621-1-shameerali.kolothum.thodi@huawei.com/ -Updated qemu-options.hx with description -Addressed review comments from Peter and Gavin(Thanks). --- include/sysemu/kvm_int.h | 1 + qemu-options.hx | 14 +++++++++ target/arm/kvm.c | 62 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 77 insertions(+) diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h index 511b42bde5..03a1660d40 100644 --- a/include/sysemu/kvm_int.h +++ b/include/sysemu/kvm_int.h @@ -116,6 +116,7 @@ struct KVMState uint64_t kvm_dirty_ring_bytes; /* Size of the per-vcpu dirty ring */ uint32_t kvm_dirty_ring_size; /* Number of dirty GFNs per ring */ bool kvm_dirty_ring_with_bitmap; + uint64_t kvm_eager_split_size; /* Eager Page Splitting chunk size */ struct KVMDirtyRingReaper reaper; NotifyVmexitOption notify_vmexit; uint32_t notify_window; diff --git a/qemu-options.hx b/qemu-options.hx index 29b98c3d4c..6ef7b89013 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -186,6 +186,7 @@ DEF("accel", HAS_ARG, QEMU_OPTION_accel, " split-wx=on|off (enable TCG split w^x mapping)\n" " tb-size=n (TCG translation block cache size)\n" " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" + " eager-split-size=n (KVM Eager Page Split chunk size, default 0, disabled. ARM only)\n" " notify-vmexit=run|internal-error|disable,notify-window=n (enable notify VM exit and set notify window, x86 only)\n" " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) SRST @@ -244,6 +245,19 @@ SRST is disabled (dirty-ring-size=0). When enabled, KVM will instead record dirty pages in a bitmap. + ``eager-split-size=n`` + KVM implements dirty page logging at the PAGE_SIZE granularity and + enabling dirty-logging on a huge-page requires breaking it into + PAGE_SIZE pages in the first place. KVM on ARM does this splitting + lazily by default. There are performance benefits in doing huge-page + split eagerly, especially in situations where TLBI costs associated + with break-before-make sequences are considerable and also if guest + workloads are read intensive. The size here specifies how many pages + to break at a time and needs to be a valid block page size(eg: 4KB | + 2M | 1G when PAGE_SIZE is 4K). Be wary of specifying a higher size as + it will have an impact on the memory. By default, this feature is + disabled (eager-split-size=0). + ``notify-vmexit=run|internal-error|disable,notify-window=n`` Enables or disables notify VM exit support on x86 host and specify the corresponding notify window to trigger the VM exit if enabled. diff --git a/target/arm/kvm.c b/target/arm/kvm.c index b4c7654f49..6ceba673d9 100644 --- a/target/arm/kvm.c +++ b/target/arm/kvm.c @@ -30,6 +30,7 @@ #include "exec/address-spaces.h" #include "hw/boards.h" #include "hw/irq.h" +#include "qapi/visitor.h" #include "qemu/log.h" const KVMCapabilityInfo kvm_arch_required_capabilities[] = { @@ -247,6 +248,11 @@ int kvm_arm_get_max_vm_ipa_size(MachineState *ms, bool *fixed_ipa) return ret > 0 ? ret : 40; } +static bool kvm_arm_eager_split_size_valid(uint64_t req_size, uint32_t sizes) +{ + return req_size & sizes; +} + int kvm_arch_init(MachineState *ms, KVMState *s) { int ret = 0; @@ -280,6 +286,22 @@ int kvm_arch_init(MachineState *ms, KVMState *s) } } + if (s->kvm_eager_split_size) { + uint32_t sizes; + + sizes = kvm_vm_check_extension(s, KVM_CAP_ARM_SUPPORTED_BLOCK_SIZES); + if (!sizes) { + s->kvm_eager_split_size = 0; + warn_report("Eager Page Split support not available"); + } else if (!kvm_arm_eager_split_size_valid(s->kvm_eager_split_size, + sizes)) { + error_report("Eager Page Split requested chunk size not valid"); + } else if (kvm_vm_enable_cap(s, KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE, 0, + s->kvm_eager_split_size)) { + error_report("Failed to set Eager Page Split chunk size"); + } + } + kvm_arm_init_debug(s); return ret; @@ -1062,6 +1084,46 @@ bool kvm_arch_cpu_check_are_resettable(void) return true; } +static void kvm_arch_get_eager_split_size(Object *obj, Visitor *v, + const char *name, void *opaque, + Error **errp) +{ + KVMState *s = KVM_STATE(obj); + uint64_t value = s->kvm_eager_split_size; + + visit_type_size(v, name, &value, errp); +} + +static void kvm_arch_set_eager_split_size(Object *obj, Visitor *v, + const char *name, void *opaque, + Error **errp) +{ + KVMState *s = KVM_STATE(obj); + uint64_t value; + + if (s->fd != -1) { + error_setg(errp, "Cannot set properties after the accelerator has been initialized"); + return; + } + + if (!visit_type_size(v, name, &value, errp)) { + return; + } + + if (is_power_of_2(value)) { + error_setg(errp, "early-split-size must be a power of two."); + return; + } + + s->kvm_eager_split_size = value; +} + void kvm_arch_accel_class_init(ObjectClass *oc) { + object_class_property_add(oc, "eager-split-size", "size", + kvm_arch_get_eager_split_size, + kvm_arch_set_eager_split_size, NULL, NULL); + + object_class_property_set_description(oc, "eager-split-size", + "Configure Eager Page Split chunk size for hugepages. (default: 0, disabled)"); }