From patchwork Wed Dec 9 20:54:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vipin Sharma X-Patchwork-Id: 11962555 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-26.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4DC78C4361B for ; Wed, 9 Dec 2020 20:56:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0B5EF23B99 for ; Wed, 9 Dec 2020 20:56:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733305AbgLIUz3 (ORCPT ); Wed, 9 Dec 2020 15:55:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39684 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733214AbgLIUzT (ORCPT ); Wed, 9 Dec 2020 15:55:19 -0500 Received: from mail-pl1-x649.google.com (mail-pl1-x649.google.com [IPv6:2607:f8b0:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AB9B4C0617A7 for ; Wed, 9 Dec 2020 12:54:28 -0800 (PST) Received: by mail-pl1-x649.google.com with SMTP id x12so1516858plr.21 for ; Wed, 09 Dec 2020 12:54:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=4wPvcXyrHKFSqikUYQ+f3mRJdXUxg4ovbfoSv1htTY8=; b=oP2KIHv0nY4YExgDPf5qblS4r/e9dzuqfV5OyerXg5CQdlobnqXCRRYjW71kHWNVB+ WtZ3LZTKgMy92tJRZwWA6ay7AICpmLknbKbzBQX1+s3WqWpd5GmzVJSHe7ofktbRLXZL Bt8Z9YnM993yaB4VybhxwDpF9nIyO3Sz7e0anQrXI43P26Yb6pH8EpQcNWSxgWtJbda9 oj2TP1cE04Y1c1FGztW5CWFU3bMd1gC8nFTOpoTeag4LZnCxQNDu3n8Osaygybab03j0 SIOW/JbgyW3OZA6IKKjvm77gqyycOXUeHBukg6jBRBbEH3tuSmOe3Wx/h2JqFI2n0Ni2 XluQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=4wPvcXyrHKFSqikUYQ+f3mRJdXUxg4ovbfoSv1htTY8=; b=rI1+YRYFp8nbxHQ3/kscRk5bv11sqwBfvCTAEl8MAuHLl5yHKf67e4WbIUegQwEhwj eEXeyElfJUIYeEeGLzjWbLwCzIA59Swq5O2M3NHNqPouPbAAK0ELUO8ZjVQq8MC7iuQ4 v9Ebn5JXzjwx3d9kgg03r0fMygymLuhQf38SUgPDYWLpvN0sid2b6ItcWWSM0d7+byHu cLFXkwYN4Sjbxa+M3/Xv+q/0p9mERV4BlReNLrF28AAZw/v9+C8t5mE6l/H7zw0ReLnE y4hBEFE7EX8XH5cZWUXUATS04m1lIqOoCxEQYblrXrYu/jDjaxSFty/AIkbWsfUpROtB PpHQ== X-Gm-Message-State: AOAM533osXKJqUdfZkb/S/6s2QSe5kgIGF76J52aKZuHlvU+GA5sGFoP 29aZTvIsSdbHnf5Agg92U5xDtEC8Ug37 X-Google-Smtp-Source: ABdhPJwtoyUBRkssYi/MYaMOhZFvZuw68rIPJjzZmJLOOxgJkjHrYQVZN2cxqKxps7cdehirWem980W1qOoq Sender: "vipinsh via sendgmr" X-Received: from vipinsh.kir.corp.google.com ([2620:0:1008:10:1ea0:b8ff:fe75:b885]) (user=vipinsh job=sendgmr) by 2002:aa7:96d8:0:b029:19e:bc79:cf7 with SMTP id h24-20020aa796d80000b029019ebc790cf7mr396004pfq.22.1607547268068; Wed, 09 Dec 2020 12:54:28 -0800 (PST) Date: Wed, 9 Dec 2020 12:54:12 -0800 In-Reply-To: <20201209205413.3391139-1-vipinsh@google.com> Message-Id: <20201209205413.3391139-2-vipinsh@google.com> Mime-Version: 1.0 References: <20201209205413.3391139-1-vipinsh@google.com> X-Mailer: git-send-email 2.29.2.576.ga3fc446d84-goog Subject: [Patch v3 1/2] cgroup: svm: Add Encryption ID controller From: Vipin Sharma To: thomas.lendacky@amd.com, brijesh.singh@amd.com, jon.grimm@amd.com, eric.vantassell@amd.com, pbonzini@redhat.com, seanjc@google.com, tj@kernel.org, lizefan@huawei.com, hannes@cmpxchg.org, frankja@linux.ibm.com, borntraeger@de.ibm.com, corbet@lwn.net Cc: joro@8bytes.org, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, gingell@google.com, rientjes@google.com, dionnaglaze@google.com, kvm@vger.kernel.org, x86@kernel.org, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Vipin Sharma , kernel test robot Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Hardware memory encryption is available on multiple generic CPUs. For example AMD has Secure Encrypted Virtualization (SEV) and SEV - Encrypted State (SEV-ES). These memory encryptions are useful in creating encrypted virtual machines (VMs) and user space programs. There are limited number of encryption IDs that can be used simultaneously on a machine for encryption. This generates a need for the system admin to track, limit, allocate resources, and optimally schedule VMs and user workloads in the cloud infrastructure. Some malicious programs can exhaust all of these resources on a host causing starvation of other workloads. Encryption ID controller allows control of these resources using Cgroups. Controller is enabled by CGROUP_ENCRYPTION_IDS config option. Encryption controller provide 3 interface files for each encryption ID type. For example, in SEV: 1. encryption_ids.sev.stat Shown only at the root cgroup. Displays total SEV IDs available on the platform and current usage count. 2. encrpytion_ids.sev.max Sets the maximum usage of SEV IDs in the cgroup. 3. encryption_ids.sev.current Current usage of SEV IDs in the cgroup and its children. Other ID types can be easily added in the controller in the same way. Signed-off-by: Vipin Sharma Reviewed-by: David Rientjes Reviewed-by: Dionna Glaze Reported-by: kernel test robot --- arch/x86/kvm/svm/sev.c | 28 +- include/linux/cgroup_subsys.h | 4 + include/linux/encryption_ids_cgroup.h | 71 +++++ include/linux/kvm_host.h | 4 + init/Kconfig | 14 + kernel/cgroup/Makefile | 1 + kernel/cgroup/encryption_ids.c | 430 ++++++++++++++++++++++++++ 7 files changed, 545 insertions(+), 7 deletions(-) create mode 100644 include/linux/encryption_ids_cgroup.h create mode 100644 kernel/cgroup/encryption_ids.c diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 566f4d18185b..83c23d1d568a 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -14,6 +14,7 @@ #include #include #include +#include #include "x86.h" #include "svm.h" @@ -77,10 +78,14 @@ static bool __sev_recycle_asids(void) return true; } -static int sev_asid_new(void) +static int sev_asid_new(struct kvm *kvm) { bool retry = true; - int pos; + int pos, ret; + + ret = enc_id_cg_try_charge(kvm, ENCRYPTION_ID_SEV, 1); + if (ret) + return ret; mutex_lock(&sev_bitmap_lock); @@ -95,7 +100,8 @@ static int sev_asid_new(void) goto again; } mutex_unlock(&sev_bitmap_lock); - return -EBUSY; + ret = -EBUSY; + goto e_uncharge; } __set_bit(pos, sev_asid_bitmap); @@ -103,6 +109,9 @@ static int sev_asid_new(void) mutex_unlock(&sev_bitmap_lock); return pos + 1; +e_uncharge: + enc_id_cg_uncharge(kvm, ENCRYPTION_ID_SEV, 1); + return ret; } static int sev_get_asid(struct kvm *kvm) @@ -112,7 +121,7 @@ static int sev_get_asid(struct kvm *kvm) return sev->asid; } -static void sev_asid_free(int asid) +static void sev_asid_free(struct kvm *kvm, int asid) { struct svm_cpu_data *sd; int cpu, pos; @@ -128,6 +137,7 @@ static void sev_asid_free(int asid) } mutex_unlock(&sev_bitmap_lock); + enc_id_cg_uncharge(kvm, ENCRYPTION_ID_SEV, 1); } static void sev_unbind_asid(struct kvm *kvm, unsigned int handle) @@ -172,7 +182,7 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp) if (unlikely(sev->active)) return ret; - asid = sev_asid_new(); + asid = sev_asid_new(kvm); if (asid < 0) return ret; @@ -187,7 +197,7 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp) return 0; e_free: - sev_asid_free(asid); + sev_asid_free(kvm, asid); return ret; } @@ -1122,7 +1132,7 @@ void sev_vm_destroy(struct kvm *kvm) mutex_unlock(&kvm->lock); sev_unbind_asid(kvm, sev->handle); - sev_asid_free(sev->asid); + sev_asid_free(kvm, sev->asid); } int __init sev_hardware_setup(void) @@ -1148,6 +1158,9 @@ int __init sev_hardware_setup(void) if (!sev_reclaim_asid_bitmap) return 1; + if (enc_id_cg_set_capacity(ENCRYPTION_ID_SEV, max_sev_asid)) + return 1; + status = kmalloc(sizeof(*status), GFP_KERNEL); if (!status) return 1; @@ -1177,6 +1190,7 @@ void sev_hardware_teardown(void) bitmap_free(sev_asid_bitmap); bitmap_free(sev_reclaim_asid_bitmap); + enc_id_cg_set_capacity(ENCRYPTION_ID_SEV, 0); sev_flush_asids(); } diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h index acb77dcff3b4..83754f58c05e 100644 --- a/include/linux/cgroup_subsys.h +++ b/include/linux/cgroup_subsys.h @@ -61,6 +61,10 @@ SUBSYS(pids) SUBSYS(rdma) #endif +#if IS_ENABLED(CONFIG_CGROUP_ENCRYPTION_IDS) +SUBSYS(encryption_ids) +#endif + /* * The following subsystems are not supported on the default hierarchy. */ diff --git a/include/linux/encryption_ids_cgroup.h b/include/linux/encryption_ids_cgroup.h new file mode 100644 index 000000000000..c450ae476de5 --- /dev/null +++ b/include/linux/encryption_ids_cgroup.h @@ -0,0 +1,71 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Encryption IDs cgroup controller. + * + * Copyright 2020 Google LLC + * Author: Vipin Sharma + */ +#ifndef _ENCRYPTION_IDS_CGROUP_H_ +#define _ENCRYPTION_IDS_CGROUP_H_ + +#include +#include + +/** + * Types of encryption IDs supported by the host. + */ +enum encryption_id_type { +#ifdef CONFIG_KVM_AMD_SEV + ENCRYPTION_ID_SEV, +#endif + ENCRYPTION_ID_TYPES +}; + +#ifdef CONFIG_CGROUP_ENCRYPTION_IDS + +/** + * struct encryption_id_res: Per cgroup per encryption ID resource + * @max: Maximum count of encryption ID that can be used. + * @usage: Current usage of encryption ID in the cgroup. + */ +struct encryption_id_res { + unsigned int max; + unsigned int usage; +}; + +/** + * struct encryption_id_cgroup - Encryption IDs controller's cgroup structure. + * @css: cgroup subsys state object. + * @ids: Array of encryption IDs resource usage in the cgroup. + */ +struct encryption_id_cgroup { + struct cgroup_subsys_state css; + struct encryption_id_res res[ENCRYPTION_ID_TYPES]; +}; + +int enc_id_cg_set_capacity(enum encryption_id_type type, unsigned int capacity); +int enc_id_cg_try_charge(struct kvm *kvm, enum encryption_id_type type, + unsigned int amount); +void enc_id_cg_uncharge(struct kvm *kvm, enum encryption_id_type type, + unsigned int amount); +#else +static inline int enc_id_cg_set_capacity(enum encryption_id_type type, + unsigned int capacity) +{ + return 0; +} + +static inline int enc_id_cg_try_charge(struct kvm *kvm, + enum encryption_id_type type, + unsigned int amount) +{ + return 0; +} + +static inline void enc_id_cg_uncharge(struct kvm *kvm, + enum encryption_id_type type, + unsigned int amount) +{ +} +#endif /* CONFIG_CGROUP_ENCRYPTION_IDS */ +#endif /* _ENCRYPTION_CGROUP_H_ */ diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 7f2e2a09ebbd..4c20b8fb1374 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -27,6 +27,7 @@ #include #include #include +#include #include #include @@ -505,6 +506,9 @@ struct kvm { struct srcu_struct irq_srcu; pid_t userspace_pid; unsigned int max_halt_poll_ns; +#ifdef CONFIG_CGROUP_ENCRYPTION_IDS + struct encryption_id_cgroup *enc_id_cg; +#endif }; #define kvm_err(fmt, ...) \ diff --git a/init/Kconfig b/init/Kconfig index 0872a5a2e759..8266acf92a54 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1106,6 +1106,20 @@ config CGROUP_BPF BPF_CGROUP_INET_INGRESS will be executed on the ingress path of inet sockets. +config CGROUP_ENCRYPTION_IDS + bool "Encryption IDs controller" + depends on KVM_AMD_SEV + default n + help + Provides a controller for CPU encryption IDs on a host. + + Some platforms have limited number of encryption IDs which can be + used simultaneously, e.g., AMD's Secure Encrypted Virtualization + (SEV). This controller tracks and limits the total number of IDs used + by processes attached to a cgroup hierarchy. For more information, + please check Encryption IDs section in + /Documentation/admin-guide/cgroup-v2.rst. + config CGROUP_DEBUG bool "Debug controller" default n diff --git a/kernel/cgroup/Makefile b/kernel/cgroup/Makefile index 5d7a76bfbbb7..6c19208dfb7f 100644 --- a/kernel/cgroup/Makefile +++ b/kernel/cgroup/Makefile @@ -5,4 +5,5 @@ obj-$(CONFIG_CGROUP_FREEZER) += legacy_freezer.o obj-$(CONFIG_CGROUP_PIDS) += pids.o obj-$(CONFIG_CGROUP_RDMA) += rdma.o obj-$(CONFIG_CPUSETS) += cpuset.o +obj-$(CONFIG_CGROUP_ENCRYPTION_IDS) += encryption_ids.o obj-$(CONFIG_CGROUP_DEBUG) += debug.o diff --git a/kernel/cgroup/encryption_ids.c b/kernel/cgroup/encryption_ids.c new file mode 100644 index 000000000000..2a3ae6b45d7c --- /dev/null +++ b/kernel/cgroup/encryption_ids.c @@ -0,0 +1,430 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Encryption IDs cgroup controller + * + * Copyright 2020 Google LLC + * Author: Vipin Sharma + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#define MAX_STR "max" +#define MAX_NUM UINT_MAX + +/* Root Encryption ID cgroup */ +static struct encryption_id_cgroup root_cg; + +/* Lock for tracking and updating encryption ID resources. */ +static DEFINE_SPINLOCK(enc_id_cg_lock); + +/* Encryption ID types capacity. */ +static unsigned int enc_id_capacity[ENCRYPTION_ID_TYPES]; + +/** + * css_enc() - Get encryption ID cgroup from the css. + * @css: cgroup subsys state object. + * + * Context: Any context. + * Return: + * * %NULL - If @css is null. + * * struct encryption_id_cgroup* - Encryption ID cgroup pointer of the passed + * css. + */ +static struct encryption_id_cgroup *css_enc(struct cgroup_subsys_state *css) +{ + return css ? container_of(css, struct encryption_id_cgroup, css) : NULL; +} + +/** + * parent_enc() - Get the parent of the passed encryption ID cgroup. + * @cgroup: cgroup whose parent needs to be fetched. + * + * Context: Any context. + * Return: + * * struct encryption_id_cgroup* - Parent of the @cgroup. + * * %NULL - If @cgroup is null or the passed cgroup does not have a parent. + */ +static struct encryption_id_cgroup * +parent_enc(struct encryption_id_cgroup *cgroup) +{ + return cgroup ? css_enc(cgroup->css.parent) : NULL; +} + +/** + * valid_type() - Check if @type is valid or not. + * @type: encryption ID type. + * + * Context: Any context. + * Return: + * * true - If valid type. + * * false - If not valid type. + */ +static inline bool valid_type(enum encryption_id_type type) +{ + return type >= 0 && type < ENCRYPTION_ID_TYPES; +} + +/** + * enc_id_cg_uncharge_hierarchy() - Uncharge the enryption ID cgroup hierarchy. + * @start_cg: Starting cgroup. + * @stop_cg: cgroup at which uncharge stops. + * @type: type of encryption ID to uncharge. + * @amount: Charge amount. + * + * Uncharge the cgroup tree from the given start cgroup to the stop cgroup. + * + * Context: Any context. Expects enc_id_cg_lock to be held by the caller. + */ +static void enc_id_cg_uncharge_hierarchy(struct encryption_id_cgroup *start_cg, + struct encryption_id_cgroup *stop_cg, + enum encryption_id_type type, + unsigned int amount) +{ + struct encryption_id_cgroup *i; + + lockdep_assert_held(&enc_id_cg_lock); + + for (i = start_cg; i != stop_cg; i = parent_enc(i)) { + WARN_ON_ONCE(i->res[type].usage < amount); + i->res[type].usage -= amount; + } + css_put(&start_cg->css); +} + +/** + * enc_id_cg_set_capacity() - Set the capacity of the encryption ID. + * @type: Type of the encryption ID. + * @capacity: Supported capacity of the encryption ID on the host. + * + * If capacity is 0 then the charging a cgroup fails for the encryption ID. + * + * Context: Any context. Takes and releases enc_id_cg_lock. + * Return: + * * %0 - Successfully registered the capacity. + * * %-EINVAL - If @type is invalid. + * * %-EBUSY - If current usage is more than the capacity. + */ +int enc_id_cg_set_capacity(enum encryption_id_type type, unsigned int capacity) +{ + int ret = 0; + unsigned long flags; + + if (!valid_type(type)) + return -EINVAL; + + spin_lock_irqsave(&enc_id_cg_lock, flags); + + if (WARN_ON_ONCE(root_cg.res[type].usage > capacity)) + ret = -EBUSY; + else + enc_id_capacity[type] = capacity; + + spin_unlock_irqrestore(&enc_id_cg_lock, flags); + + return ret; +} +EXPORT_SYMBOL(enc_id_cg_set_capacity); + +/** + * enc_id_cg_try_charge() - Try charging encryption ID cgroup. + * @kvm: kvm to store charged cgroup. + * @type: Encryption ID type to charge. + * @amount: Amount to charge. + * + * Charge @amount to the cgroup to which the current task belongs to. Charged + * cgroup will be pointed by @cg. Caller must use the same cgroup during + * uncharge call. + * + * Context: Any context. Takes and releases enc_id_cg_lock. + * Return: + * * %0 - If successfully charged. + * * -EINVAL - If @type is invalid or encryption ID has 0 capacity. + * * -EBUSY - If max limit will be crossed or total usage will be more than the + * capacity. + */ +int enc_id_cg_try_charge(struct kvm *kvm, enum encryption_id_type type, + unsigned int amount) +{ + struct encryption_id_cgroup *task_cg, *i; + struct encryption_id_res *id_res; + int ret; + unsigned int new_usage; + unsigned long flags; + + if (!valid_type(type) || !kvm) + return -EINVAL; + + if (!amount) + return 0; + + spin_lock_irqsave(&enc_id_cg_lock, flags); + + if (!enc_id_capacity[type]) { + ret = -EINVAL; + goto err_capacity; + } + + task_cg = css_enc(task_get_css(current, encryption_ids_cgrp_id)); + + for (i = task_cg; i; i = parent_enc(i)) { + id_res = &i->res[type]; + + new_usage = id_res->usage + amount; + WARN_ON_ONCE(new_usage < id_res->usage); + + if (new_usage > id_res->max || + new_usage > enc_id_capacity[type]) { + ret = -EBUSY; + goto err_charge; + } + + id_res->usage = new_usage; + } + + kvm->enc_id_cg = task_cg; + spin_unlock_irqrestore(&enc_id_cg_lock, flags); + return 0; + +err_charge: + enc_id_cg_uncharge_hierarchy(task_cg, i, type, amount); +err_capacity: + spin_unlock_irqrestore(&enc_id_cg_lock, flags); + return ret; +} +EXPORT_SYMBOL(enc_id_cg_try_charge); + +/** + * enc_id_cg_uncharge() - Uncharge the encryption ID cgroup. + * @kvm: kvm containing the corresponding encryption ID cgroup. + * @type: Encryption ID which was charged. + * @amount: Charged amount. + * + * Context: Any context. Takes and releases enc_id_cg_lock. + */ +void enc_id_cg_uncharge(struct kvm *kvm, enum encryption_id_type type, + unsigned int amount) +{ + unsigned long flags; + + if (!amount) + return; + if (!valid_type(type)) + return; + if (!kvm || WARN_ON_ONCE(!(kvm->enc_id_cg))) + return; + + spin_lock_irqsave(&enc_id_cg_lock, flags); + enc_id_cg_uncharge_hierarchy(kvm->enc_id_cg, NULL, type, amount); + spin_unlock_irqrestore(&enc_id_cg_lock, flags); + + kvm->enc_id_cg = NULL; +} +EXPORT_SYMBOL(enc_id_cg_uncharge); + +/** + * enc_id_cg_max_show() - Show encryption ID cgroup max limit. + * @sf: Interface file + * @v: Arguments passed + * + * Uses cft->private value to determine for which enryption ID type results be + * shown. + * + * Context: Any context. + * Return: 0 to denote successful print. + */ +static int enc_id_cg_max_show(struct seq_file *sf, void *v) +{ + struct encryption_id_cgroup *cg = css_enc(seq_css(sf)); + enum encryption_id_type type = seq_cft(sf)->private; + + if (cg->res[type].max == MAX_NUM) + seq_printf(sf, "%s\n", MAX_STR); + else + seq_printf(sf, "%u\n", cg->res[type].max); + + return 0; +} + +/** + * enc_id_cg_max_write() - Update the maximum limit of the cgroup. + * @of: Handler for the file. + * @buf: Data from the user. It should be either "max", 0, or a positive + * integer. + * @nbytes: Number of bytes of the data. + * @off: Offset in the file. + * + * Uses cft->private value to determine for which enryption ID type results be + * shown. + * + * Context: Any context. Takes and releases enc_id_cg_lock. + * Return: + * * >= 0 - Number of bytes processed in the input. + * * -EINVAL - If buf is not valid. + * * -ERANGE - If number is bigger than unsigned int capacity. + * * -EBUSY - If usage can become more than max limit. + */ +static ssize_t enc_id_cg_max_write(struct kernfs_open_file *of, char *buf, + size_t nbytes, loff_t off) +{ + struct encryption_id_cgroup *cg; + unsigned int max; + int ret = 0; + unsigned long flags; + enum encryption_id_type type; + + buf = strstrip(buf); + if (!strcmp(MAX_STR, buf)) { + max = UINT_MAX; + } else { + ret = kstrtouint(buf, 0, &max); + if (ret) + return ret; + } + + cg = css_enc(of_css(of)); + type = of_cft(of)->private; + + spin_lock_irqsave(&enc_id_cg_lock, flags); + + if (cg->res[type].usage <= max) + cg->res[type].max = max; + else + ret = -EBUSY; + + spin_unlock_irqrestore(&enc_id_cg_lock, flags); + + return ret ? ret : nbytes; +} + +/** + * enc_id_cg_current_read() - Show current usage of the encryption ID. + * @css: css pointer of the cgroup. + * @cft: cft pointer of the cgroup. + * + * Uses cft->private value to determine for which enryption ID type results be + * shown. + * + * Context: Any context. + * Return: 0 to denote successful print. + */ +static u64 enc_id_cg_current_read(struct cgroup_subsys_state *css, + struct cftype *cft) +{ + struct encryption_id_cgroup *cg = css_enc(css); + enum encryption_id_type type = cft->private; + + return cg->res[type].usage; +} + +/** + * enc_id_cg_stat_show() - Show the current stat of the cgroup. + * @sf: Interface file + * @v: Arguments passed + * + * Shows the total capacity of the encryption ID and its current usage. + * Only shows in root cgroup directory. + * + * Uses cft->private value to determine for which enryption ID type results be + * shown. + * + * Context: Any context. Takes and releases enc_id_cg_lock. + * Return: 0 to denote successful print. + */ +static int enc_id_cg_stat_show(struct seq_file *sf, void *v) +{ + unsigned long flags; + enum encryption_id_type type = seq_cft(sf)->private; + + spin_lock_irqsave(&enc_id_cg_lock, flags); + + seq_printf(sf, "total %u\n", enc_id_capacity[type]); + seq_printf(sf, "used %u\n", root_cg.res[type].usage); + + spin_unlock_irqrestore(&enc_id_cg_lock, flags); + return 0; +} + +/* Each encryption ID type has these cgroup files. */ +#define ENC_ID_CGROUP_FILES(id_name, id_type) \ + [(id_type) * 3] = { \ + .name = id_name ".max", \ + .write = enc_id_cg_max_write, \ + .seq_show = enc_id_cg_max_show, \ + .flags = CFTYPE_NOT_ON_ROOT, \ + .private = id_type, \ + }, \ + [((id_type) * 3) + 1] = { \ + .name = id_name ".current", \ + .read_u64 = enc_id_cg_current_read, \ + .flags = CFTYPE_NOT_ON_ROOT, \ + .private = id_type, \ + }, \ + [((id_type) * 3) + 2] = { \ + .name = id_name ".stat", \ + .seq_show = enc_id_cg_stat_show, \ + .flags = CFTYPE_ONLY_ON_ROOT, \ + .private = id_type, \ + } + +/* Encryption ID cgroup interface files */ +static struct cftype enc_id_cg_files[] = { +#ifdef CONFIG_KVM_AMD_SEV + ENC_ID_CGROUP_FILES("sev", ENCRYPTION_ID_SEV), +#endif + {} +}; + +/** + * enc_id_cg_alloc() - Allocate encryption ID cgroup. + * @parent_css: Parent cgroup. + * + * Context: Process context. + * Return: + * * struct cgroup_subsys_state* - css of the allocated cgroup. + * * ERR_PTR(-ENOMEM) - No memory available to allocate. + */ +static struct cgroup_subsys_state * +enc_id_cg_alloc(struct cgroup_subsys_state *parent_css) +{ + enum encryption_id_type i; + struct encryption_id_cgroup *cg; + + if (!parent_css) { + cg = &root_cg; + } else { + cg = kzalloc(sizeof(*cg), GFP_KERNEL); + if (!cg) + return ERR_PTR(-ENOMEM); + } + + for (i = 0; i < ENCRYPTION_ID_TYPES; i++) + cg->res[i].max = MAX_NUM; + + return &cg->css; +} + +/** + * enc_id_cg_free() - Free the encryption ID cgroup. + * @css: cgroup subsys object. + * + * Context: Any context. + */ +static void enc_id_cg_free(struct cgroup_subsys_state *css) +{ + kfree(css_enc(css)); +} + +/* Cgroup controller callbacks */ +struct cgroup_subsys encryption_ids_cgrp_subsys = { + .css_alloc = enc_id_cg_alloc, + .css_free = enc_id_cg_free, + .legacy_cftypes = enc_id_cg_files, + .dfl_cftypes = enc_id_cg_files, +}; 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From: Vipin Sharma To: thomas.lendacky@amd.com, brijesh.singh@amd.com, jon.grimm@amd.com, eric.vantassell@amd.com, pbonzini@redhat.com, seanjc@google.com, tj@kernel.org, lizefan@huawei.com, hannes@cmpxchg.org, frankja@linux.ibm.com, borntraeger@de.ibm.com, corbet@lwn.net Cc: joro@8bytes.org, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, gingell@google.com, rientjes@google.com, dionnaglaze@google.com, kvm@vger.kernel.org, x86@kernel.org, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Vipin Sharma Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Documentation for both cgroup versions, v1 and v2, of Encryption IDs controller. This new controller is used to track and limit usage of hardware memory encryption capabilities on the CPUs. Signed-off-by: Vipin Sharma Reviewed-by: David Rientjes Reviewed-by: Dionna Glaze --- .../admin-guide/cgroup-v1/encryption_ids.rst | 108 ++++++++++++++++++ Documentation/admin-guide/cgroup-v2.rst | 78 ++++++++++++- 2 files changed, 184 insertions(+), 2 deletions(-) create mode 100644 Documentation/admin-guide/cgroup-v1/encryption_ids.rst diff --git a/Documentation/admin-guide/cgroup-v1/encryption_ids.rst b/Documentation/admin-guide/cgroup-v1/encryption_ids.rst new file mode 100644 index 000000000000..891143b4e229 --- /dev/null +++ b/Documentation/admin-guide/cgroup-v1/encryption_ids.rst @@ -0,0 +1,108 @@ +========================= +Encryption IDs Controller +========================= + +Overview +======== +There are multiple hardware memory encryption capabilities provided by the +hardware vendors, like Secure Encrypted Virtualization (SEV) and SEV Encrypted +State (SEV-ES) from AMD. + +These features are being used in encrypting virtual machines (VMs) and user +space programs. However, only a small number of keys/IDs can be used +simultaneously. + +This limited availability of these IDs requires system admin to optimize +allocation, control, and track the usage of the resources in the cloud +infrastructure. This resource also needs to be protected from getting exhausted +by some malicious program and causing starvation for other programs. + +Encryption IDs controller provides capability to register the resource for +controlling and tracking through the cgroups. + +How to Enable Controller +======================== + +- Enable Encryption controller:: + + CONFIG_CGROUP_ENCRYPTION_IDS=y + +- Above options will build Encryption controller support in the kernel. + To mount the Encryption controller:: + + mount -t cgroup -o encryption none /sys/fs/cgroup/encryption + + +Interface Files +=============== +Each encryption ID type have their own interface files, +encryption_id.[ID TYPE].{max, current, stat}, where "ID TYPE" can be sev and +sev-es. + + encryption_ids.[ID TYPE].stat + A read-only flat-keyed single value file. This file exists only in the + root cgroup. + + It shows the total number of encryption IDs available and currently in + use on the platform:: + # cat encryption.sev.stat + total 509 + used 0 + + encryption_ids.[ID TYPE].max + A read-write file which exists on the non-root cgroups. File is used to + set maximum count of "[ID TYPE]" which can be used in the cgroup. + + Limit can be set to max by:: + # echo max > encryption.sev.max + + Limit can be set by:: + # echo 100 > encryption.sev.max + + This file shows the max limit of the encryption ID in the cgroup:: + # cat encryption.sev.max + max + + OR:: + # cat encryption.sev.max + 100 + + Limits can be set more than the "total" capacity value in the + encryption_ids.[ID TYPE].stat file, however, the controller ensures + that the usage never exceeds the "total" and the max limit. + + encryption_ids.[ID TYPE].current + A read-only single value file which exists on non-root cgroups. + + Shows the total number of encrypted IDs being used in the cgroup. + +Hierarchy +========= + +Encryption IDs controller supports hierarchical accounting. It supports +following features: + +1. Current usage in the cgroup shows IDs used in the cgroup and its descendent cgroups. +2. Current usage can never exceed the corresponding max limit set in the cgroup + and its ancestor's chain up to the root. + +Suppose the following example hierarchy:: + + root + / \ + A B + | + C + +1. A will show the count of IDs used in A and C. +2. C's current IDs usage may not exceed any of the max limits set in C, A, or + root. + +Migration and ownership +======================= + +An encryption ID is charged to the cgroup in which it is used first, and +stays charged to that cgroup until that ID is freed. Migrating a process +to a different cgroup do not move the charge to the destination cgroup +where the process has moved. + diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 608d7c279396..7938bb7c6e1c 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -63,8 +63,11 @@ v1 is available under :ref:`Documentation/admin-guide/cgroup-v1/index.rst encryption.sev.max + + Limit can be set by:: + # echo 100 > encryption.sev.max + + This file shows the max limit of the encryption ID in the cgroup:: + # cat encryption.sev.max + max + + OR:: + # cat encryption.sev.max + 100 + + Limits can be set more than the "total" capacity value in the + encryption_ids.[ID TYPE].stat file, however, the controller ensures + that the usage never exceeds the "total" and the max limit. + + encryption_ids.[ID TYPE].current + A read-only single value file which exists on non-root cgroups. + + Shows the total number of encrypted IDs being used in the cgroup. + +Migration and Ownership +~~~~~~~~~~~~~~~~~~~~~~~ + +An encryption ID is charged to the cgroup in which it is used first, and +stays charged to that cgroup until that ID is freed. Migrating a process +to a different cgroup do not move the charge to the destination cgroup +where the process has moved. + Misc ----