From patchwork Fri Aug 26 16:05:02 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhiquan Li X-Patchwork-Id: 12956250 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 993B0ECAAA3 for ; Fri, 26 Aug 2022 16:00:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236165AbiHZQAB (ORCPT ); Fri, 26 Aug 2022 12:00:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49666 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237347AbiHZQAA (ORCPT ); Fri, 26 Aug 2022 12:00:00 -0400 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A3063E760 for ; Fri, 26 Aug 2022 08:59:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1661529599; x=1693065599; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=QIgkWeMjiLK/v/87I2wwyB2fNdV8OV5KhTA255s1qWQ=; b=FgrDCg7/4RkAsMayVYea8cehWhSL2P2BMcMITCIEIDj7MzhPONqwPahM VFGW0LG+DqcYiSmg0d3c6mrJE73soRhir6j2xGgwrfzOEaaeO44r4tTg9 ly+KhkvRvQFqwKdt931IQ9oRQ/DnL61hKMYMPBcDNX0OpcI42wOgltETK YiyCCKVnZv3hAgHSqVFJYPcpSHSbV4O6scKTdkcOnrwRUcpQCbQEPFWch 7tu6pjAaEDUsmKxzRg6il3Vm3jm1youmIEBatMiigUR126LR1pM5XuyOQ /0oGmD9AXcpZ47t4wbJYioNaBrvWQzUfWA+O9XfHiqr0p6wK+KiInTK25 A==; X-IronPort-AV: E=McAfee;i="6500,9779,10451"; a="274288837" X-IronPort-AV: E=Sophos;i="5.93,265,1654585200"; d="scan'208";a="274288837" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Aug 2022 08:59:42 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.93,265,1654585200"; d="scan'208";a="587342996" Received: from zhiquan-linux-dev.bj.intel.com ([10.238.155.101]) by orsmga006.jf.intel.com with ESMTP; 26 Aug 2022 08:59:39 -0700 From: Zhiquan Li To: linux-sgx@vger.kernel.org, tony.luck@intel.com, jarkko@kernel.org, dave.hansen@linux.intel.com, tglx@linutronix.de, bp@alien8.de Cc: seanjc@google.com, kai.huang@intel.com, fan.du@intel.com, cathy.zhang@intel.com, zhiquan1.li@intel.com Subject: [PATCH RESEND v6 2/3] x86/sgx: Introduce union with vepc_vaddr field for virtualization case Date: Sat, 27 Aug 2022 00:05:02 +0800 Message-Id: <20220826160503.1576966-3-zhiquan1.li@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220826160503.1576966-1-zhiquan1.li@intel.com> References: <20220826160503.1576966-1-zhiquan1.li@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org When a page triggers a machine check, it only reports the PFN. But in order to inject #MC into hypervisor, the virtual address is required. The 'encl_owner' field is useless in virtualization case, then repurpose it as 'vepc_vaddr' - the virtual address of the virtual EPC page for such case so that arch_memory_failure() can easily retrieve it. Introduce a union to prevent adding a new dedicated structure to track the virtual address of virtual EPC page. And it can also prevent playing the casting games while using it. Add a new EPC page flag - SGX_EPC_PAGE_KVM_GUEST to interpret the meaning of the field. Co-developed-by: Cathy Zhang Signed-off-by: Cathy Zhang Signed-off-by: Zhiquan Li Acked-by: Kai Huang Reviewed-by: Jarkko Sakkinen --- Changes since V5: - To prevent casting the 'encl_owner' field, introduce a union with another field - 'vepc_vaddr', sugguested by Dave Hansen. - Add Reviewed-by from Jarkko. Link: https://lore.kernel.org/linux-sgx/Yrf27fugD7lkyaek@kernel.org/T/#m379d00fc7f1d43726a42b3884637532061a8c0d1 Changes since V4: - Add Co-developed-by and Signed-off-by from Cathy Zhang, as she had fully discussed the flag name with Jarkko. Link: https://lore.kernel.org/all/df92395ade424401ac3c6322de568720@intel.com/ - Add Acked-by from Kai Huang Link: https://lore.kernel.org/linux-sgx/0676cd4e-d94b-e904-81ae-ca1c05d37070@intel.com/T/#mccfb11df30698dbd060f2b6f06383cda7f154ef3 Changes since V3: - Take the definition of EPC page flag SGX_EPC_PAGE_KVM_GUEST from Cathy Zhang's third patch of SGX rebootless recovery patch set but discard irrelevant portion, since it might need some time to re-forge and these are two different features. Link: https://lore.kernel.org/linux-sgx/41704e5d4c03b49fcda12e695595211d950cfb08.camel@kernel.org/T/#m9782d23496cacecb7da07a67daa79f4b322ae170 Changes since V2: - Remove struct sgx_vepc_page and relevant code. - Rework the patch suggested by Jarkko. - Remove new EPC page flag SGX_EPC_PAGE_IS_VEPC definition as it is duplicated to SGX_EPC_PAGE_KVM_GUEST. Link: https://lore.kernel.org/linux-sgx/eb95b32ecf3d44a695610cf7f2816785@intel.com/T/#u Changes since V1: - Add documentation suggested by Jarkko. --- arch/x86/kernel/cpu/sgx/main.c | 4 ++++ arch/x86/kernel/cpu/sgx/sgx.h | 8 +++++++- arch/x86/kernel/cpu/sgx/virt.c | 4 +++- 3 files changed, 14 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 1315c69a733e..b319bedcaf1e 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -549,6 +549,10 @@ int sgx_unmark_page_reclaimable(struct sgx_epc_page *page) * Finally, wake up ksgxd when the number of pages goes below the watermark * before returning back to the caller. * + * When an EPC page is assigned to KVM guest, repurpose the 'encl_owner' field + * as the virtual address of virtual EPC page, since it is useless in such + * scenario, so 'owner' is assigned to 'vepc_vaddr'. + * * Return: * an EPC page, * -errno on error diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h index 4d88abccd12e..d16a8baa28d4 100644 --- a/arch/x86/kernel/cpu/sgx/sgx.h +++ b/arch/x86/kernel/cpu/sgx/sgx.h @@ -28,12 +28,18 @@ /* Pages on free list */ #define SGX_EPC_PAGE_IS_FREE BIT(1) +/* Pages allocated for KVM guest */ +#define SGX_EPC_PAGE_KVM_GUEST BIT(2) struct sgx_epc_page { unsigned int section; u16 flags; u16 poison; - struct sgx_encl_page *encl_owner; + union { + struct sgx_encl_page *encl_owner; + /* Use when SGX_EPC_PAGE_KVM_GUEST set in ->flags: */ + void __user *vepc_vaddr; + }; struct list_head list; }; diff --git a/arch/x86/kernel/cpu/sgx/virt.c b/arch/x86/kernel/cpu/sgx/virt.c index 6a77a14eee38..776ae5c1c032 100644 --- a/arch/x86/kernel/cpu/sgx/virt.c +++ b/arch/x86/kernel/cpu/sgx/virt.c @@ -46,10 +46,12 @@ static int __sgx_vepc_fault(struct sgx_vepc *vepc, if (epc_page) return 0; - epc_page = sgx_alloc_epc_page(vepc, false); + epc_page = sgx_alloc_epc_page((void *)addr, false); if (IS_ERR(epc_page)) return PTR_ERR(epc_page); + epc_page->flags |= SGX_EPC_PAGE_KVM_GUEST; + ret = xa_err(xa_store(&vepc->page_array, index, epc_page, GFP_KERNEL)); if (ret) goto err_free;