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 A58EEC433F5 for ; Wed, 2 Mar 2022 14:29:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243100AbiCBOaf (ORCPT ); Wed, 2 Mar 2022 09:30:35 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43500 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235393AbiCBO3u (ORCPT ); Wed, 2 Mar 2022 09:29:50 -0500 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9C8AB546A2 for ; Wed, 2 Mar 2022 06:28:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1646231304; x=1677767304; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=EvrY+fLFyt0AjjIeJc3eqvET5iI6uNtGs7idg2+y+vU=; b=ajG+t/MCMmeHA0rSSocLgr1kMoM4k/yYlMD11EXJIT1cWd49+SA/l/Dh pQVGjO0NBgf2H4uU5Xu0qphLF8ygjZ3wFVsr99XABGyUh/wD00vv1hAAD ezSLYyFw6r5dWl7NUVOUWfzYs4Da5nyZ68kJt8STv8fzY9pJr2fciitb5 EzrrISqWldzqXtQB88ZDCFhAVMyS+eZalSkYT/KzeI1ripg4mqa/ZSi/6 UM8/q0u/I0mmIa0oGXBTRnXObf2eocHvkZQ+Cnloxc4ehB0ZxBL9vRQ5c sQsqjSgUBStoXajxMP/M12OutqKMvFU4Fw3/BSNKvUHJHRmWaQqM0/XHh A==; X-IronPort-AV: E=McAfee;i="6200,9189,10274"; a="253336392" X-IronPort-AV: E=Sophos;i="5.90,149,1643702400"; d="scan'208";a="253336392" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Mar 2022 06:28:16 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.90,149,1643702400"; d="scan'208";a="493553207" Received: from black.fi.intel.com ([10.237.72.28]) by orsmga003.jf.intel.com with ESMTP; 02 Mar 2022 06:28:09 -0800 Received: by black.fi.intel.com (Postfix, from userid 1000) id D98595C0; Wed, 2 Mar 2022 16:28:12 +0200 (EET) From: "Kirill A. Shutemov" To: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@intel.com, luto@kernel.org, peterz@infradead.org Cc: sathyanarayanan.kuppuswamy@linux.intel.com, aarcange@redhat.com, ak@linux.intel.com, dan.j.williams@intel.com, david@redhat.com, hpa@zytor.com, jgross@suse.com, jmattson@google.com, joro@8bytes.org, jpoimboe@redhat.com, knsathya@kernel.org, pbonzini@redhat.com, sdeep@vmware.com, seanjc@google.com, tony.luck@intel.com, vkuznets@redhat.com, wanpengli@tencent.com, thomas.lendacky@amd.com, brijesh.singh@amd.com, x86@kernel.org, linux-kernel@vger.kernel.org, Sean Christopherson , "Rafael J . Wysocki" , "Kirill A . Shutemov" Subject: [PATCHv5 21/30] x86/acpi, x86/boot: Add multiprocessor wake-up support Date: Wed, 2 Mar 2022 17:27:57 +0300 Message-Id: <20220302142806.51844-22-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220302142806.51844-1-kirill.shutemov@linux.intel.com> References: <20220302142806.51844-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kuppuswamy Sathyanarayanan TDX cannot use INIT/SIPI protocol to bring up secondary CPUs because it requires assistance from untrusted VMM. For platforms that do not support SIPI/INIT, ACPI defines a wakeup model (using mailbox) via MADT multiprocessor wakeup structure. More details about it can be found in ACPI specification v6.4, the section titled "Multiprocessor Wakeup Structure". If a platform firmware produces the multiprocessor wakeup structure, then OS may use this new mailbox-based mechanism to wake up the APs. Add ACPI MADT wake structure parsing support for x86 platform and if MADT wake table is present, update apic->wakeup_secondary_cpu_64 with new API which uses MADT wake mailbox to wake-up CPU. Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson Reviewed-by: Andi Kleen Reviewed-by: Rafael J. Wysocki Signed-off-by: Kuppuswamy Sathyanarayanan Signed-off-by: Kirill A. Shutemov --- arch/x86/include/asm/apic.h | 5 ++ arch/x86/kernel/acpi/boot.c | 118 ++++++++++++++++++++++++++++++++++++ arch/x86/kernel/apic/apic.c | 10 +++ 3 files changed, 133 insertions(+) diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h index 35006e151774..bd8ae0a7010a 100644 --- a/arch/x86/include/asm/apic.h +++ b/arch/x86/include/asm/apic.h @@ -490,6 +490,11 @@ static inline unsigned int read_apic_id(void) return apic->get_apic_id(reg); } +#ifdef CONFIG_X86_64 +typedef int (*wakeup_cpu_handler)(int apicid, unsigned long start_eip); +extern void acpi_wake_cpu_handler_update(wakeup_cpu_handler handler); +#endif + extern int default_apic_id_valid(u32 apicid); extern int default_acpi_madt_oem_check(char *, char *); extern void default_setup_apic_routing(void); diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index 5b6d1a95776f..99518eac2bbc 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -65,6 +65,15 @@ static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE; static bool acpi_support_online_capable; #endif +#ifdef CONFIG_X86_64 +/* Physical address of the Multiprocessor Wakeup Structure mailbox */ +static u64 acpi_mp_wake_mailbox_paddr; +/* Virtual address of the Multiprocessor Wakeup Structure mailbox */ +static struct acpi_madt_multiproc_wakeup_mailbox *acpi_mp_wake_mailbox; +/* Lock to protect mailbox (acpi_mp_wake_mailbox) from parallel access */ +static DEFINE_SPINLOCK(mailbox_lock); +#endif + #ifdef CONFIG_X86_IO_APIC /* * Locks related to IOAPIC hotplug @@ -336,6 +345,84 @@ acpi_parse_lapic_nmi(union acpi_subtable_headers * header, const unsigned long e return 0; } +#ifdef CONFIG_X86_64 +/* Virtual address of the Multiprocessor Wakeup Structure mailbox */ +static int acpi_wakeup_cpu(int apicid, unsigned long start_ip) +{ + static physid_mask_t apic_id_wakemap = PHYSID_MASK_NONE; + u8 timeout; + + /* Remap mailbox memory only for the first call to acpi_wakeup_cpu() */ + if (physids_empty(apic_id_wakemap)) { + acpi_mp_wake_mailbox = memremap(acpi_mp_wake_mailbox_paddr, + sizeof(*acpi_mp_wake_mailbox), + MEMREMAP_WB); + } + + /* + * According to the ACPI specification r6.4, section titled + * "Multiprocessor Wakeup Structure" the mailbox-based wakeup + * mechanism cannot be used more than once for the same CPU. + * Skip wakeups if they are attempted more than once. + */ + if (physid_isset(apicid, apic_id_wakemap)) { + pr_err("CPU already awake (APIC ID %x), skipping wakeup\n", + apicid); + return -EINVAL; + } + + spin_lock(&mailbox_lock); + + /* + * Mailbox memory is shared between firmware and OS. Firmware will + * listen on mailbox command address, and once it receives the wakeup + * command, CPU associated with the given apicid will be booted. + * + * The value of apic_id and wakeup_vector has to be set before updating + * the wakeup command. To let compiler preserve order of writes, use + * smp_store_release. + */ + smp_store_release(&acpi_mp_wake_mailbox->apic_id, apicid); + smp_store_release(&acpi_mp_wake_mailbox->wakeup_vector, start_ip); + smp_store_release(&acpi_mp_wake_mailbox->command, + ACPI_MP_WAKE_COMMAND_WAKEUP); + + /* + * After writing the wakeup command, wait for maximum timeout of 0xFF + * for firmware to reset the command address back zero to indicate + * the successful reception of command. + * NOTE: 0xFF as timeout value is decided based on our experiments. + * + * XXX: Change the timeout once ACPI specification comes up with + * standard maximum timeout value. + */ + timeout = 0xFF; + while (READ_ONCE(acpi_mp_wake_mailbox->command) && --timeout) + cpu_relax(); + + /* If timed out (timeout == 0), return error */ + if (!timeout) { + /* + * XXX: Is there a recovery path after timeout is hit? + * Spec is unclear. Reset command to 0 if timeout is hit. + */ + acpi_mp_wake_mailbox->command = 0; + spin_unlock(&mailbox_lock); + return -EIO; + } + + /* + * If the CPU wakeup process is successful, store the + * status in apic_id_wakemap to prevent re-wakeup + * requests. + */ + physid_set(apicid, apic_id_wakemap); + + spin_unlock(&mailbox_lock); + + return 0; +} +#endif #endif /*CONFIG_X86_LOCAL_APIC */ #ifdef CONFIG_X86_IO_APIC @@ -1083,6 +1170,29 @@ static int __init acpi_parse_madt_lapic_entries(void) } return 0; } + +#ifdef CONFIG_X86_64 +static int __init acpi_parse_mp_wake(union acpi_subtable_headers *header, + const unsigned long end) +{ + struct acpi_madt_multiproc_wakeup *mp_wake; + + if (!IS_ENABLED(CONFIG_SMP)) + return -ENODEV; + + mp_wake = (struct acpi_madt_multiproc_wakeup *)header; + if (BAD_MADT_ENTRY(mp_wake, end)) + return -EINVAL; + + acpi_table_print_madt_entry(&header->common); + + acpi_mp_wake_mailbox_paddr = mp_wake->base_address; + + acpi_wake_cpu_handler_update(acpi_wakeup_cpu); + + return 0; +} +#endif /* CONFIG_X86_64 */ #endif /* CONFIG_X86_LOCAL_APIC */ #ifdef CONFIG_X86_IO_APIC @@ -1278,6 +1388,14 @@ static void __init acpi_process_madt(void) smp_found_config = 1; } + +#ifdef CONFIG_X86_64 + /* + * Parse MADT MP Wake entry. + */ + acpi_table_parse_madt(ACPI_MADT_TYPE_MULTIPROC_WAKEUP, + acpi_parse_mp_wake, 1); +#endif } if (error == -EINVAL) { /* diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index b70344bf6600..3c8f2c797a98 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2551,6 +2551,16 @@ u32 x86_msi_msg_get_destid(struct msi_msg *msg, bool extid) } EXPORT_SYMBOL_GPL(x86_msi_msg_get_destid); +#ifdef CONFIG_X86_64 +void __init acpi_wake_cpu_handler_update(wakeup_cpu_handler handler) +{ + struct apic **drv; + + for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) + (*drv)->wakeup_secondary_cpu_64 = handler; +} +#endif + /* * Override the generic EOI implementation with an optimized version. * Only called during early boot when only one CPU is active and with -- 2.34.1