From patchwork Sat Jul 23 12:23:41 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhiquan Li X-Patchwork-Id: 12927175 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 134BEC43334 for ; Sat, 23 Jul 2022 12:19:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231602AbiGWMTA (ORCPT ); Sat, 23 Jul 2022 08:19:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48196 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229462AbiGWMS7 (ORCPT ); Sat, 23 Jul 2022 08:18:59 -0400 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AE318AE50 for ; Sat, 23 Jul 2022 05:18:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1658578738; x=1690114738; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=4wAq9W1SZtCZ/oWfGvGii6y7hMKlFuvtDNM/25r3Axc=; b=mJiFx1Tpg44quc/6y+W3T/5ibFDgRlFAn9hy+LMozticvqNafvI1vNZE tNPZKNS7xphiiU3BHnX8dGlhV+wHo/kwXEIhdVdTunJHNolIEG1+I9EhK ZUaHH5hW/XnZFiyNu+viBD2XHRzGTp6omzmMfOWYS3E9/ayeEMao+QDSm q8Hmx/kWLb2A95wI6TPcMgFzEh1Ft7cNqEPPziWkNJrnIAj1b0qBe3Z77 5icP2634Sq2c15FCNuT3dqvO4jwDxcP1i1lM7er2ZUYh1F8jBirMMz/Vj rL5K0Ob+s6sWsQvPLE3lEf3kD1VJgpUMJR+5To2rPRh9wrKwfvSeIoF7J Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10416"; a="351461303" X-IronPort-AV: E=Sophos;i="5.93,188,1654585200"; d="scan'208";a="351461303" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Jul 2022 05:18:58 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.93,188,1654585200"; d="scan'208";a="596215045" Received: from zhiquan-linux-dev.bj.intel.com ([10.238.155.101]) by orsmga007.jf.intel.com with ESMTP; 23 Jul 2022 05:18:55 -0700 From: Zhiquan Li To: linux-sgx@vger.kernel.org, tony.luck@intel.com, jarkko@kernel.org, dave.hansen@linux.intel.com Cc: seanjc@google.com, kai.huang@intel.com, fan.du@intel.com, cathy.zhang@intel.com, zhiquan1.li@intel.com Subject: [PATCH v6 1/3] x86/sgx: Rename the owner field of struct sgx_epc_page as encl_owner Date: Sat, 23 Jul 2022 20:23:41 +0800 Message-Id: <20220723122343.598783-2-zhiquan1.li@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220723122343.598783-1-zhiquan1.li@intel.com> References: <20220723122343.598783-1-zhiquan1.li@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org In order to describe the purpose of 'owner' field more exactly, rename the 'owner' field of struct sgx_epc_page as 'encl_owner', and update all of references. Signed-off-by: Zhiquan Li --- arch/x86/kernel/cpu/sgx/main.c | 20 ++++++++++---------- arch/x86/kernel/cpu/sgx/sgx.h | 2 +- 2 files changed, 11 insertions(+), 11 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 5acd4c54d904..6b5c3633cb8e 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -102,7 +102,7 @@ static void __sgx_sanitize_pages(struct list_head *dirty_page_list) static bool sgx_reclaimer_age(struct sgx_epc_page *epc_page) { - struct sgx_encl_page *page = epc_page->owner; + struct sgx_encl_page *page = epc_page->encl_owner; struct sgx_encl *encl = page->encl; struct sgx_encl_mm *encl_mm; bool ret = true; @@ -134,7 +134,7 @@ static bool sgx_reclaimer_age(struct sgx_epc_page *epc_page) static void sgx_reclaimer_block(struct sgx_epc_page *epc_page) { - struct sgx_encl_page *page = epc_page->owner; + struct sgx_encl_page *page = epc_page->encl_owner; unsigned long addr = page->desc & PAGE_MASK; struct sgx_encl *encl = page->encl; int ret; @@ -191,7 +191,7 @@ void sgx_ipi_cb(void *info) static void sgx_encl_ewb(struct sgx_epc_page *epc_page, struct sgx_backing *backing) { - struct sgx_encl_page *encl_page = epc_page->owner; + struct sgx_encl_page *encl_page = epc_page->encl_owner; struct sgx_encl *encl = encl_page->encl; struct sgx_va_page *va_page; unsigned int va_offset; @@ -244,7 +244,7 @@ static void sgx_encl_ewb(struct sgx_epc_page *epc_page, static void sgx_reclaimer_write(struct sgx_epc_page *epc_page, struct sgx_backing *backing) { - struct sgx_encl_page *encl_page = epc_page->owner; + struct sgx_encl_page *encl_page = epc_page->encl_owner; struct sgx_encl *encl = encl_page->encl; struct sgx_backing secs_backing; int ret; @@ -306,7 +306,7 @@ static void sgx_reclaim_pages(void) epc_page = list_first_entry(&sgx_active_page_list, struct sgx_epc_page, list); list_del_init(&epc_page->list); - encl_page = epc_page->owner; + encl_page = epc_page->encl_owner; if (kref_get_unless_zero(&encl_page->encl->refcount) != 0) chunk[cnt++] = epc_page; @@ -320,7 +320,7 @@ static void sgx_reclaim_pages(void) for (i = 0; i < cnt; i++) { epc_page = chunk[i]; - encl_page = epc_page->owner; + encl_page = epc_page->encl_owner; if (!sgx_reclaimer_age(epc_page)) goto skip; @@ -359,7 +359,7 @@ static void sgx_reclaim_pages(void) if (!epc_page) continue; - encl_page = epc_page->owner; + encl_page = epc_page->encl_owner; sgx_reclaimer_write(epc_page, &backing[i]); kref_put(&encl_page->encl->refcount, sgx_encl_release); @@ -555,7 +555,7 @@ struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim) for ( ; ; ) { page = __sgx_alloc_epc_page(); if (!IS_ERR(page)) { - page->owner = owner; + page->encl_owner = owner; break; } @@ -598,7 +598,7 @@ void sgx_free_epc_page(struct sgx_epc_page *page) spin_lock(&node->lock); - page->owner = NULL; + page->encl_owner = NULL; if (page->poison) list_add(&page->list, &node->sgx_poison_page_list); else @@ -633,7 +633,7 @@ static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size, for (i = 0; i < nr_pages; i++) { section->pages[i].section = index; section->pages[i].flags = 0; - section->pages[i].owner = NULL; + section->pages[i].encl_owner = NULL; section->pages[i].poison = 0; list_add_tail(§ion->pages[i].list, &sgx_dirty_page_list); } diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h index 0f2020653fba..4d88abccd12e 100644 --- a/arch/x86/kernel/cpu/sgx/sgx.h +++ b/arch/x86/kernel/cpu/sgx/sgx.h @@ -33,7 +33,7 @@ struct sgx_epc_page { unsigned int section; u16 flags; u16 poison; - struct sgx_encl_page *owner; + struct sgx_encl_page *encl_owner; struct list_head list; }; From patchwork Sat Jul 23 12:23:42 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhiquan Li X-Patchwork-Id: 12927176 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 9DCDFC43334 for ; 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X-IronPort-AV: E=McAfee;i="6400,9594,10416"; a="351461306" X-IronPort-AV: E=Sophos;i="5.93,188,1654585200"; d="scan'208";a="351461306" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Jul 2022 05:19:06 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.93,188,1654585200"; d="scan'208";a="596215060" Received: from zhiquan-linux-dev.bj.intel.com ([10.238.155.101]) by orsmga007.jf.intel.com with ESMTP; 23 Jul 2022 05:19:03 -0700 From: Zhiquan Li To: linux-sgx@vger.kernel.org, tony.luck@intel.com, jarkko@kernel.org, dave.hansen@linux.intel.com Cc: seanjc@google.com, kai.huang@intel.com, fan.du@intel.com, cathy.zhang@intel.com, zhiquan1.li@intel.com Subject: [PATCH v6 2/3] x86/sgx: Introduce union with vepc_vaddr field for virtualization case Date: Sat, 23 Jul 2022 20:23:42 +0800 Message-Id: <20220723122343.598783-3-zhiquan1.li@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220723122343.598783-1-zhiquan1.li@intel.com> References: <20220723122343.598783-1-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 in 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'. - 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 6b5c3633cb8e..542fa420b3f7 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -544,6 +544,10 @@ 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; From patchwork Sat Jul 23 12:23:43 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhiquan Li X-Patchwork-Id: 12927177 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 BE833C43334 for ; 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X-IronPort-AV: E=McAfee;i="6400,9594,10416"; a="274322770" X-IronPort-AV: E=Sophos;i="5.93,188,1654585200"; d="scan'208";a="274322770" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Jul 2022 05:19:13 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.93,188,1654585200"; d="scan'208";a="596215075" Received: from zhiquan-linux-dev.bj.intel.com ([10.238.155.101]) by orsmga007.jf.intel.com with ESMTP; 23 Jul 2022 05:19:10 -0700 From: Zhiquan Li To: linux-sgx@vger.kernel.org, tony.luck@intel.com, jarkko@kernel.org, dave.hansen@linux.intel.com Cc: seanjc@google.com, kai.huang@intel.com, fan.du@intel.com, cathy.zhang@intel.com, zhiquan1.li@intel.com Subject: [PATCH v6 3/3] x86/sgx: Fine grained SGX MCA behavior for virtualization Date: Sat, 23 Jul 2022 20:23:43 +0800 Message-Id: <20220723122343.598783-4-zhiquan1.li@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220723122343.598783-1-zhiquan1.li@intel.com> References: <20220723122343.598783-1-zhiquan1.li@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org Today, if a guest accesses an SGX EPC page with memory failure, the kernel behavior will kill the entire guest. This blast radius is too large. It would be idea to kill only the SGX application inside the guest. To fix this, send a SIGBUS to host userspace (like QEMU) which can follow up by injecting a #MC to the guest. SGX virtual EPC driver doesn't explicitly prevent virtual EPC instance being shared by multiple VMs via fork(). However KVM doesn't support running a VM across multiple mm structures, and the de facto userspace hypervisor (Qemu) doesn't use fork() to create a new VM, so in practice this should not happen. Signed-off-by: Zhiquan Li Acked-by: Kai Huang Link: https://lore.kernel.org/linux-sgx/443cb425-009c-2784-56f4-5e707122de76@intel.com/T/#m1d1f4098f4fad78034e8706a60e4d79c119db407 Reviewed-by: Jarkko Sakkinen --- Changes since V5: - Use the 'vepc_vaddr' field instead of casting the 'owner' field. - Clean up the commit message suggested by Dave. Link: https://lore.kernel.org/linux-sgx/Yrf27fugD7lkyaek@kernel.org/T/#m2ff4778948cdc9ee65f09672f1d02f8dc467247b - Add Reviewed-by from Jarkko. Changes since V4: - Switch the order of the two variables so all of variables are in reverse Christmas style. - Do not initialize "ret" because it will be overridden by the return value of force_sig_mceerr() unconditionally. Changes since V2: - Retrieve virtual address from "owner" field of struct sgx_epc_page, instead of struct sgx_vepc_page. - Replace EPC page flag SGX_EPC_PAGE_IS_VEPC with SGX_EPC_PAGE_KVM_GUEST as they are duplicated. Changes since V1: - Add Acked-by from Kai Huang. - Add Kai's excellent explanation regarding to why we no need to consider that one virtual EPC be shared by two guests. --- arch/x86/kernel/cpu/sgx/main.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 542fa420b3f7..3e724068b40b 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -674,6 +674,8 @@ int arch_memory_failure(unsigned long pfn, int flags) struct sgx_epc_page *page = sgx_paddr_to_page(pfn << PAGE_SHIFT); struct sgx_epc_section *section; struct sgx_numa_node *node; + void __user * vaddr; + int ret; /* * mm/memory-failure.c calls this routine for all errors @@ -690,8 +692,26 @@ int arch_memory_failure(unsigned long pfn, int flags) * error. The signal may help the task understand why the * enclave is broken. */ - if (flags & MF_ACTION_REQUIRED) - force_sig(SIGBUS); + if (flags & MF_ACTION_REQUIRED) { + /* + * Provide extra info to the task so that it can make further + * decision but not simply kill it. This is quite useful for + * virtualization case. + */ + if (page->flags & SGX_EPC_PAGE_KVM_GUEST) { + /* + * The 'encl_owner' field is repurposed, when allocating EPC + * page it was assigned to the virtual address of virtual EPC + * page. + */ + vaddr = (unsigned long)page->vepc_vaddr & PAGE_MASK; + ret = force_sig_mceerr(BUS_MCEERR_AR, vaddr, PAGE_SHIFT); + if (ret < 0) + pr_err("Memory failure: Error sending signal to %s:%d: %d\n", + current->comm, current->pid, ret); + } else + force_sig(SIGBUS); + } section = &sgx_epc_sections[page->section]; node = section->node;