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 E98D1C678D5 for ; Thu, 9 Mar 2023 01:38:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229692AbjCIBio (ORCPT ); Wed, 8 Mar 2023 20:38:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50734 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229453AbjCIBim (ORCPT ); Wed, 8 Mar 2023 20:38:42 -0500 Received: from mail-pl1-x631.google.com (mail-pl1-x631.google.com [IPv6:2607:f8b0:4864:20::631]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4C57361325; Wed, 8 Mar 2023 17:38:40 -0800 (PST) Received: by mail-pl1-x631.google.com with SMTP id n6so443310plf.5; Wed, 08 Mar 2023 17:38:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1678325920; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=Wp3o55iwIqO/cQywxFHBxXSCvkugjaxyj31RwoGSFKg=; b=UH6JEbvd/ykwh7fsvqi9gbHbU8yl+6TsEUQzdKxH2NOhDKBtLlU54jM7M4DWKd5lWX hHDGMJoWRb6LpVE2eVjLtQZ7uRc4wOUfBbjgY7fegXhUdiL3E2E68AltbhlFseNIzvH9 jPCzHY2MHMlkevldqQ0CpZ8vPP68/YVQTegTYhG23iCVVeinem9i+8mrmKMnS6Qxm5hH 4HivmZUNlKJ76VbYS3mI6Lfp51bqMWJ4TqcQa++6j6wGtRzriZflqP2xYwRQ6ZMkMJ5X qFAh5GI7rPas5JwtUY7QWEArUj62UYVz5x25fFnbUP9unNJtjNjZUagdc14kieKj/qRz zQCw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678325920; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=Wp3o55iwIqO/cQywxFHBxXSCvkugjaxyj31RwoGSFKg=; b=aNGTnJcg4tc7cEWTrg15zq3oaGTbZkJiYQTNNcnXfagbUlbPXQiClNLYyjfDqcpd0u Yq+uXShSBwxlAjtussQTfX9liGdGcNuroNzvzSn64oT5Jjsv1FVQLXqLUepticsaGFp5 hrpoyCyMF73Y8aYcy5ZYP7XBfvOOrlmCZd6ioqPfTbgfStRYtiAeDMuX2bG4hXCS296r yFhzq6b3F8ddBO8mFJlTMKofg/rVFL1eLlkYe1FYibP3CHfeEM+1KYnn0KDsV6yPln8r wJz1CjvOH8PEnjIZfZjPUnpOCVIbmWnpOtyCmIu09h35C7FW3WQOJfxvjaujOJBCeTKw hVzg== X-Gm-Message-State: AO0yUKUyes6BNb780uYawe0lgFXfI7psYsYgGtf0cWIvuhNUz8B7Vni2 mGhuSC8Pu07GMXHVXku1iU0= X-Google-Smtp-Source: AK7set9arh2+gFYeQLft4AIJwux/hUYwguebeXgQFddvIHaxevyi/n+OlB9KWVLWSK1QZ+loNHSXmQ== X-Received: by 2002:a17:902:ab41:b0:196:44d4:2453 with SMTP id ij1-20020a170902ab4100b0019644d42453mr15876987plb.7.1678325919381; Wed, 08 Mar 2023 17:38:39 -0800 (PST) Received: from localhost ([192.55.54.55]) by smtp.gmail.com with ESMTPSA id lf16-20020a170902fb5000b0019edf5532d2sm3324497plb.306.2023.03.08.17.38.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 08 Mar 2023 17:38:38 -0800 (PST) Date: Wed, 8 Mar 2023 17:38:37 -0800 From: Isaku Yamahata To: Kai Huang Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, dave.hansen@intel.com, peterz@infradead.org, tglx@linutronix.de, seanjc@google.com, pbonzini@redhat.com, dan.j.williams@intel.com, rafael.j.wysocki@intel.com, kirill.shutemov@linux.intel.com, ying.huang@intel.com, reinette.chatre@intel.com, len.brown@intel.com, tony.luck@intel.com, ak@linux.intel.com, isaku.yamahata@intel.com, chao.gao@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, david@redhat.com, bagasdotme@gmail.com, sagis@google.com, imammedo@redhat.com, isaku.yamahata@gmail.com Subject: Re: [PATCH v10 07/16] x86/virt/tdx: Use all system memory when initializing TDX module as TDX memory Message-ID: <20230309013837.GB3419702@ls.amr.corp.intel.com> References: <54fce4052e700a78843b5672c5380ffaf3879902.1678111292.git.kai.huang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <54fce4052e700a78843b5672c5380ffaf3879902.1678111292.git.kai.huang@intel.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, Mar 07, 2023 at 03:13:52AM +1300, Kai Huang wrote: > As a step of initializing the TDX module, the kernel needs to tell the > TDX module which memory regions can be used by the TDX module as TDX > guest memory. > > TDX reports a list of "Convertible Memory Region" (CMR) to tell the > kernel which memory is TDX compatible. The kernel needs to build a list > of memory regions (out of CMRs) as "TDX-usable" memory and pass them to > the TDX module. Once this is done, those "TDX-usable" memory regions > are fixed during module's lifetime. > > To keep things simple, assume that all TDX-protected memory will come > from the page allocator. Make sure all pages in the page allocator > *are* TDX-usable memory. > > As TDX-usable memory is a fixed configuration, take a snapshot of the > memory configuration from memblocks at the time of module initialization > (memblocks are modified on memory hotplug). This snapshot is used to > enable TDX support for *this* memory configuration only. Use a memory > hotplug notifier to ensure that no other RAM can be added outside of > this configuration. > > This approach requires all memblock memory regions at the time of module > initialization to be TDX convertible memory to work, otherwise module > initialization will fail in a later SEAMCALL when passing those regions > to the module. This approach works when all boot-time "system RAM" is > TDX convertible memory, and no non-TDX-convertible memory is hot-added > to the core-mm before module initialization. > > For instance, on the first generation of TDX machines, both CXL memory > and NVDIMM are not TDX convertible memory. Using kmem driver to hot-add > any CXL memory or NVDIMM to the core-mm before module initialization > will result in failure to initialize the module. The SEAMCALL error > code will be available in the dmesg to help user to understand the > failure. > > Signed-off-by: Kai Huang > Reviewed-by: "Huang, Ying" > --- > > v9 -> v10: > - Moved empty @tdx_memlist check out of is_tdx_memory() to make the > logic better. > - Added Ying's Reviewed-by. > > v8 -> v9: > - Replace "The initial support ..." with timeless sentence in both > changelog and comments(Dave). > - Fix run-on sentence in changelog, and senstence to explain why to > stash off memblock (Dave). > - Tried to improve why to choose this approach and how it work in > changelog based on Dave's suggestion. > - Many other comments enhancement (Dave). > > v7 -> v8: > - Trimed down changelog (Dave). > - Changed to use PHYS_PFN() and PFN_PHYS() throughout this series > (Ying). > - Moved memory hotplug handling from add_arch_memory() to > memory_notifier (Dan/David). > - Removed 'nid' from 'struct tdx_memblock' to later patch (Dave). > - {build|free}_tdx_memory() -> {build|}free_tdx_memlist() (Dave). > - Removed pfn_covered_by_cmr() check as no code to trim CMRs now. > - Improve the comment around first 1MB (Dave). > - Added a comment around reserve_real_mode() to point out TDX code > relies on first 1MB being reserved (Ying). > - Added comment to explain why the new online memory range cannot > cross multiple TDX memory blocks (Dave). > - Improved other comments (Dave). > > --- > arch/x86/Kconfig | 1 + > arch/x86/kernel/setup.c | 2 + > arch/x86/virt/vmx/tdx/tdx.c | 165 +++++++++++++++++++++++++++++++++++- > arch/x86/virt/vmx/tdx/tdx.h | 6 ++ > 4 files changed, 172 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index 6dd5d5586099..f23bc540778a 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -1958,6 +1958,7 @@ config INTEL_TDX_HOST > depends on X86_64 > depends on KVM_INTEL > depends on X86_X2APIC > + select ARCH_KEEP_MEMBLOCK > help > Intel Trust Domain Extensions (TDX) protects guest VMs from malicious > host and certain physical attacks. This option enables necessary TDX > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c > index 88188549647c..a8a119a9b48c 100644 > --- a/arch/x86/kernel/setup.c > +++ b/arch/x86/kernel/setup.c > @@ -1165,6 +1165,8 @@ void __init setup_arch(char **cmdline_p) > * > * Moreover, on machines with SandyBridge graphics or in setups that use > * crashkernel the entire 1M is reserved anyway. > + * > + * Note the host kernel TDX also requires the first 1MB being reserved. > */ > x86_platform.realmode_reserve(); > > diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c > index 981e11492d0e..9149144cd7e7 100644 > --- a/arch/x86/virt/vmx/tdx/tdx.c > +++ b/arch/x86/virt/vmx/tdx/tdx.c > @@ -17,6 +17,13 @@ > #include > #include > #include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > #include > #include > #include > @@ -39,6 +46,9 @@ static DEFINE_PER_CPU(unsigned int, tdx_lp_init_status); > static enum tdx_module_status_t tdx_module_status; > static DEFINE_MUTEX(tdx_module_lock); > > +/* All TDX-usable memory regions. Protected by mem_hotplug_lock. */ > +static LIST_HEAD(tdx_memlist); > + > /* > * Use tdx_global_keyid to indicate that TDX is uninitialized. > * This is used in TDX initialization error paths to take it from > @@ -77,6 +87,54 @@ static int __init record_keyid_partitioning(u32 *tdx_keyid_start, > return 0; > } > > +static bool is_tdx_memory(unsigned long start_pfn, unsigned long end_pfn) > +{ > + struct tdx_memblock *tmb; > + > + /* > + * This check assumes that the start_pfn<->end_pfn range does not > + * cross multiple @tdx_memlist entries. A single memory online > + * event across multiple memblocks (from which @tdx_memlist > + * entries are derived at the time of module initialization) is > + * not possible. This is because memory offline/online is done > + * on granularity of 'struct memory_block', and the hotpluggable > + * memory region (one memblock) must be multiple of memory_block. > + */ > + list_for_each_entry(tmb, &tdx_memlist, list) { > + if (start_pfn >= tmb->start_pfn && end_pfn <= tmb->end_pfn) > + return true; > + } > + return false; > +} > + > +static int tdx_memory_notifier(struct notifier_block *nb, unsigned long action, > + void *v) > +{ > + struct memory_notify *mn = v; > + > + if (action != MEM_GOING_ONLINE) > + return NOTIFY_OK; > + > + /* > + * Empty list means TDX isn't enabled. Allow any memory > + * to go online. > + */ > + if (list_empty(&tdx_memlist)) > + return NOTIFY_OK; > + > + /* > + * The TDX memory configuration is static and can not be > + * changed. Reject onlining any memory which is outside of > + * the static configuration whether it supports TDX or not. > + */ > + return is_tdx_memory(mn->start_pfn, mn->start_pfn + mn->nr_pages) ? > + NOTIFY_OK : NOTIFY_BAD; > +} > + > +static struct notifier_block tdx_memory_nb = { > + .notifier_call = tdx_memory_notifier, > +}; > + > static int __init tdx_init(void) > { > u32 tdx_keyid_start, nr_tdx_keyids; > @@ -107,6 +165,13 @@ static int __init tdx_init(void) > goto no_tdx; > } > > + err = register_memory_notifier(&tdx_memory_nb); > + if (err) { > + pr_info("initialization failed: register_memory_notifier() failed (%d)\n", > + err); > + goto no_tdx; > + } > + > tdx_guest_keyid_start = tdx_keyid_start; > tdx_nr_guest_keyids = nr_tdx_keyids; > > @@ -316,6 +381,79 @@ static int tdx_get_sysinfo(struct tdsysinfo_struct *sysinfo, > return 0; > } > > +/* > + * Add a memory region as a TDX memory block. The caller must make sure > + * all memory regions are added in address ascending order and don't > + * overlap. > + */ > +static int add_tdx_memblock(struct list_head *tmb_list, unsigned long start_pfn, > + unsigned long end_pfn) > +{ > + struct tdx_memblock *tmb; > + > + tmb = kmalloc(sizeof(*tmb), GFP_KERNEL); > + if (!tmb) > + return -ENOMEM; > + > + INIT_LIST_HEAD(&tmb->list); > + tmb->start_pfn = start_pfn; > + tmb->end_pfn = end_pfn; > + > + /* @tmb_list is protected by mem_hotplug_lock */ > + list_add_tail(&tmb->list, tmb_list); > + return 0; > +} > + > +static void free_tdx_memlist(struct list_head *tmb_list) > +{ > + /* @tmb_list is protected by mem_hotplug_lock */ > + while (!list_empty(tmb_list)) { > + struct tdx_memblock *tmb = list_first_entry(tmb_list, > + struct tdx_memblock, list); > + > + list_del(&tmb->list); > + kfree(tmb); > + } > +} > + > +/* > + * Ensure that all memblock memory regions are convertible to TDX > + * memory. Once this has been established, stash the memblock > + * ranges off in a secondary structure because memblock is modified > + * in memory hotplug while TDX memory regions are fixed. > + */ > +static int build_tdx_memlist(struct list_head *tmb_list) > +{ > + unsigned long start_pfn, end_pfn; > + int i, ret; > + > + for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) { > + /* > + * The first 1MB is not reported as TDX convertible memory. > + * Although the first 1MB is always reserved and won't end up > + * to the page allocator, it is still in memblock's memory > + * regions. Skip them manually to exclude them as TDX memory. > + */ > + start_pfn = max(start_pfn, PHYS_PFN(SZ_1M)); > + if (start_pfn >= end_pfn) > + continue; > + > + /* > + * Add the memory regions as TDX memory. The regions in > + * memblock has already guaranteed they are in address > + * ascending order and don't overlap. > + */ > + ret = add_tdx_memblock(tmb_list, start_pfn, end_pfn); > + if (ret) > + goto err; > + } > + > + return 0; > +err: > + free_tdx_memlist(tmb_list); > + return ret; > +} > + > static int init_tdx_module(void) > { > static DECLARE_PADDED_STRUCT(tdsysinfo_struct, tdsysinfo, > @@ -329,10 +467,25 @@ static int init_tdx_module(void) > if (ret) > return ret; > > + /* > + * To keep things simple, assume that all TDX-protected memory > + * will come from the page allocator. Make sure all pages in the > + * page allocator are TDX-usable memory. > + * > + * Build the list of "TDX-usable" memory regions which cover all > + * pages in the page allocator to guarantee that. Do it while > + * holding mem_hotplug_lock read-lock as the memory hotplug code > + * path reads the @tdx_memlist to reject any new memory. > + */ > + get_online_mems(); > + > + ret = build_tdx_memlist(&tdx_memlist); > + if (ret) > + goto out; > + > /* > * TODO: > * > - * - Build the list of TDX-usable memory regions. > * - Construct a list of "TD Memory Regions" (TDMRs) to cover > * all TDX-usable memory regions. > * - Configure the TDMRs and the global KeyID to the TDX module. > @@ -341,7 +494,15 @@ static int init_tdx_module(void) > * > * Return error before all steps are done. > */ > - return -EINVAL; > + ret = -EINVAL; > +out: > + /* > + * @tdx_memlist is written here and read at memory hotplug time. > + * Lock out memory hotplug code while building it. > + */ > + put_online_mems(); > + > + return ret; > } > > static int __tdx_enable(void) > diff --git a/arch/x86/virt/vmx/tdx/tdx.h b/arch/x86/virt/vmx/tdx/tdx.h > index 2f2d8737a364..6518024fcb68 100644 > --- a/arch/x86/virt/vmx/tdx/tdx.h > +++ b/arch/x86/virt/vmx/tdx/tdx.h > @@ -101,6 +101,12 @@ enum tdx_module_status_t { > TDX_MODULE_ERROR > }; > > +struct tdx_memblock { > + struct list_head list; > + unsigned long start_pfn; > + unsigned long end_pfn; > +}; > + > struct tdx_module_output; > u64 __seamcall(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9, > struct tdx_module_output *out); > -- > 2.39.2 > Reviewed-by: Isaku Yamahata -- Isaku Yamahata