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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1274DC4332F for ; Tue, 12 Oct 2021 10:57:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EDE06603E8 for ; Tue, 12 Oct 2021 10:57:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236149AbhJLK7S (ORCPT ); Tue, 12 Oct 2021 06:59:18 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:47620 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236123AbhJLK7Q (ORCPT ); Tue, 12 Oct 2021 06:59:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1634036234; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=y4eOMfi0FRdlOEtX16+L00odJNz+Fuq7wcCV5MOdEm8=; b=KicSKvUzyvbBlmz1UMYvnNZNoYusMwFurqb0gURcBJvm87cnNWo5Kqeh7IWG9+HW6kkKPV qlSO1VEelVEPVG7loBghowx8oJFc5x4M5CYhMSgxkzUc2UaejxBeC3fQSd2E6W2Lh19tOT hJHapuRW8xFMw/GEJ4DDmbBn2R0Ve/c= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-193-GapcTHaRMwCjVdsyjau27w-1; Tue, 12 Oct 2021 06:57:11 -0400 X-MC-Unique: GapcTHaRMwCjVdsyjau27w-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1CC7C1018720; Tue, 12 Oct 2021 10:57:10 +0000 (UTC) Received: from virtlab701.virt.lab.eng.bos.redhat.com (virtlab701.virt.lab.eng.bos.redhat.com [10.19.152.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id 846BD5D6D5; Tue, 12 Oct 2021 10:57:09 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: dave.hansen@linux.intel.com, seanjc@google.com, x86@kernel.org, yang.zhong@intel.com, jarkko@kernel.org Subject: [PATCH v2 1/2] x86: sgx_vepc: extract sgx_vepc_remove_page Date: Tue, 12 Oct 2021 06:57:07 -0400 Message-Id: <20211012105708.2070480-2-pbonzini@redhat.com> In-Reply-To: <20211012105708.2070480-1-pbonzini@redhat.com> References: <20211012105708.2070480-1-pbonzini@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org For bare-metal SGX on real hardware, the hardware provides guarantees SGX state at reboot. For instance, all pages start out uninitialized. The vepc driver provides a similar guarantee today for freshly-opened vepc instances, but guests such as Windows expect all pages to be in uninitialized state on startup, including after every guest reboot. One way to do this is to simply close and reopen the /dev/sgx_vepc file descriptor and re-mmap the virtual EPC. However, this is problematic because it prevents sandboxing the userspace (for example forbidding open() after the guest starts; this is doable with heavy use of SCM_RIGHTS file descriptor passing). In order to implement this, we will need a ioctl that performs EREMOVE on all pages mapped by a /dev/sgx_vepc file descriptor: other possibilities, such as closing and reopening the device, are racy. Start the implementation by creating a separate function with just the __eremove wrapper. Signed-off-by: Paolo Bonzini --- v1->v2: keep WARN in sgx_vepc_free_page arch/x86/kernel/cpu/sgx/virt.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/virt.c b/arch/x86/kernel/cpu/sgx/virt.c index 64511c4a5200..59cdf3f742ac 100644 --- a/arch/x86/kernel/cpu/sgx/virt.c +++ b/arch/x86/kernel/cpu/sgx/virt.c @@ -111,10 +111,8 @@ static int sgx_vepc_mmap(struct file *file, struct vm_area_struct *vma) return 0; } -static int sgx_vepc_free_page(struct sgx_epc_page *epc_page) +static int sgx_vepc_remove_page(struct sgx_epc_page *epc_page) { - int ret; - /* * Take a previously guest-owned EPC page and return it to the * general EPC page pool. @@ -124,7 +122,12 @@ static int sgx_vepc_free_page(struct sgx_epc_page *epc_page) * case that a guest properly EREMOVE'd this page, a superfluous * EREMOVE is harmless. */ - ret = __eremove(sgx_get_epc_virt_addr(epc_page)); + return __eremove(sgx_get_epc_virt_addr(epc_page)); +} + +static int sgx_vepc_free_page(struct sgx_epc_page *epc_page) +{ + int ret = sgx_vepc_remove_page(epc_page); if (ret) { /* * Only SGX_CHILD_PRESENT is expected, which is because of @@ -144,7 +147,6 @@ static int sgx_vepc_free_page(struct sgx_epc_page *epc_page) } sgx_free_epc_page(epc_page); - return 0; } -- 2.27.0