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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3EEF3C433EF for ; Thu, 21 Jul 2022 11:05:49 +0000 (UTC) Received: from localhost ([::1]:56736 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oEU03-0002o3-W5 for qemu-devel@archiver.kernel.org; Thu, 21 Jul 2022 07:05:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45538) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oETuv-00019L-DI for qemu-devel@nongnu.org; Thu, 21 Jul 2022 07:00:30 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:51013) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oETut-0005DS-2I for qemu-devel@nongnu.org; Thu, 21 Jul 2022 07:00:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1658401226; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=3COIscdvLsIYKk+bah8UB5GUuzOh7aMOH1So4xvoybE=; b=Mq2kCqMghz63S7BxY0cQ4KinBr6x5yA4gH3I1dcA2WfrvjW2bgj8c2jI5sv3EsOWeijy35 ZR9oRDkwUx+eO2T2q8cJHMiMDrJkR7SXgJBm/oBg5DvldB8oZzOJFCRbk7KwJ8Za7bnANp 4De1qjup1FdWWrTehZnI8QYbbBy5pto= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-218-mzO5VM2zMM6Bbz07d3eL1g-1; Thu, 21 Jul 2022 07:00:19 -0400 X-MC-Unique: mzO5VM2zMM6Bbz07d3eL1g-1 Received: by mail-wr1-f72.google.com with SMTP id n10-20020a5d6b8a000000b0021da91e4a64so238897wrx.8 for ; Thu, 21 Jul 2022 04:00:19 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=3COIscdvLsIYKk+bah8UB5GUuzOh7aMOH1So4xvoybE=; b=L7s/ibmQPeBU1YURjniRfEh4HL/Qe55LZbKpJY1Sn3Ixc891HWmQ3IWJB5RDlJNBrK ErDPME0Xmw7MeTL5VxiRY5e6zKJ7Ojif7z/LdDkCmH2lWJr3wPguY7IIVEmBWq/9Whx+ DIsysD4Pw1bjqTT8pDOgAcr0PvCS9X0GzyhUA/wQGH8r8WOe2KQKzZkJIJ31/H/6ofkY KEYSGURE/x/K/KAihqxk70xzpm77qDX7GbKgQ4X4ZbseMnO8PnYf/BweMJAROJDb8sfn bICEi5ML55i8Iq84CoL/BpqxGOZILadV3NwKcG9GUCLV6Mff8f8jUMaPehv5+/VMB6fv NDDA== X-Gm-Message-State: AJIora/5xkPKrX0hNIWyLyjVnCAyMdyMka57vsSckWeFv3oOP/WuZQat byY6rbk7NuKRxBr9LFm5VvdxJMEg0dui0z3/w0EAnJFIi55K8mqZKsOQRfBypL03pQTb1BqLNjq 8Tx4j5BFHkmNxdR4= X-Received: by 2002:a05:600c:4110:b0:3a3:33cd:3984 with SMTP id j16-20020a05600c411000b003a333cd3984mr1232910wmi.128.1658401218318; Thu, 21 Jul 2022 04:00:18 -0700 (PDT) X-Google-Smtp-Source: AGRyM1vFbI6v+Gfzf9pYU/IWVqLuIMBUctvyNaZpTTODAPgD5BbO7AnfbAp93QregDQKgr6FrCNW2A== X-Received: by 2002:a05:600c:4110:b0:3a3:33cd:3984 with SMTP id j16-20020a05600c411000b003a333cd3984mr1232877wmi.128.1658401217909; Thu, 21 Jul 2022 04:00:17 -0700 (PDT) Received: from redhat.com ([2.55.25.63]) by smtp.gmail.com with ESMTPSA id i4-20020a05600c354400b003a326b84340sm5677193wmq.44.2022.07.21.04.00.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 Jul 2022 04:00:17 -0700 (PDT) Date: Thu, 21 Jul 2022 07:00:12 -0400 From: "Michael S. Tsirkin" To: "Jason A. Donenfeld" Cc: pbonzini@redhat.com, qemu-devel@nongnu.org, Marcel Apfelbaum , Richard Henderson , Eduardo Habkost , Peter Maydell , Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= , Laurent Vivier Subject: Re: [PATCH v6] hw/i386: pass RNG seed via setup_data entry Message-ID: <20220721065744-mutt-send-email-mst@kernel.org> References: <20220721104730.434017-1-Jason@zx2c4.com> <20220721104950.434544-1-Jason@zx2c4.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220721104950.434544-1-Jason@zx2c4.com> Received-SPF: pass client-ip=170.10.133.124; envelope-from=mst@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Jul 21, 2022 at 12:49:50PM +0200, Jason A. Donenfeld wrote: > Tiny machines optimized for fast boot time generally don't use EFI, > which means a random seed has to be supplied some other way. For this > purpose, Linux (≥5.20) supports passing a seed in the setup_data table > with SETUP_RNG_SEED, specially intended for hypervisors, kexec, and > specialized bootloaders. The linked commit shows the upstream kernel > implementation. > > Link: https://git.kernel.org/tip/tip/c/68b8e9713c8 > Cc: Michael S. Tsirkin > Cc: Marcel Apfelbaum > Cc: Paolo Bonzini > Cc: Richard Henderson > Cc: Eduardo Habkost > Cc: Peter Maydell > Cc: Philippe Mathieu-Daudé > Cc: Laurent Vivier > Signed-off-by: Jason A. Donenfeld Well why not. Reviewed-by: Michael S. Tsirkin who's merging this? Paolo me or you? > --- > hw/i386/x86.c | 21 +++++++++++++++++--- > include/standard-headers/asm-x86/bootparam.h | 1 + > 2 files changed, 19 insertions(+), 3 deletions(-) > > diff --git a/hw/i386/x86.c b/hw/i386/x86.c > index 6003b4b2df..56896cb4b2 100644 > --- a/hw/i386/x86.c > +++ b/hw/i386/x86.c > @@ -26,6 +26,7 @@ > #include "qemu/cutils.h" > #include "qemu/units.h" > #include "qemu/datadir.h" > +#include "qemu/guest-random.h" > #include "qapi/error.h" > #include "qapi/qmp/qerror.h" > #include "qapi/qapi-visit-common.h" > @@ -774,7 +775,7 @@ void x86_load_linux(X86MachineState *x86ms, > int dtb_size, setup_data_offset; > uint32_t initrd_max; > uint8_t header[8192], *setup, *kernel; > - hwaddr real_addr, prot_addr, cmdline_addr, initrd_addr = 0; > + hwaddr real_addr, prot_addr, cmdline_addr, initrd_addr = 0, first_setup_data = 0; > FILE *f; > char *vmode; > MachineState *machine = MACHINE(x86ms); > @@ -784,6 +785,7 @@ void x86_load_linux(X86MachineState *x86ms, > const char *dtb_filename = machine->dtb; > const char *kernel_cmdline = machine->kernel_cmdline; > SevKernelLoaderContext sev_load_ctx = {}; > + enum { RNG_SEED_LENGTH = 32 }; > > /* Align to 16 bytes as a paranoia measure */ > cmdline_size = (strlen(kernel_cmdline) + 16) & ~15; > @@ -1063,16 +1065,29 @@ void x86_load_linux(X86MachineState *x86ms, > kernel_size = setup_data_offset + sizeof(struct setup_data) + dtb_size; > kernel = g_realloc(kernel, kernel_size); > > - stq_p(header + 0x250, prot_addr + setup_data_offset); > > setup_data = (struct setup_data *)(kernel + setup_data_offset); > - setup_data->next = 0; > + setup_data->next = cpu_to_le64(first_setup_data); > + first_setup_data = prot_addr + setup_data_offset; > setup_data->type = cpu_to_le32(SETUP_DTB); > setup_data->len = cpu_to_le32(dtb_size); > > load_image_size(dtb_filename, setup_data->data, dtb_size); > } > > + setup_data_offset = QEMU_ALIGN_UP(kernel_size, 16); > + kernel_size = setup_data_offset + sizeof(struct setup_data) + RNG_SEED_LENGTH; > + kernel = g_realloc(kernel, kernel_size); > + setup_data = (struct setup_data *)(kernel + setup_data_offset); > + setup_data->next = cpu_to_le64(first_setup_data); > + first_setup_data = prot_addr + setup_data_offset; > + setup_data->type = cpu_to_le32(SETUP_RNG_SEED); > + setup_data->len = cpu_to_le32(RNG_SEED_LENGTH); > + qemu_guest_getrandom_nofail(setup_data->data, RNG_SEED_LENGTH); > + > + /* Offset 0x250 is a pointer to the first setup_data link. */ > + stq_p(header + 0x250, first_setup_data); > + > /* > * If we're starting an encrypted VM, it will be OVMF based, which uses the > * efi stub for booting and doesn't require any values to be placed in the > diff --git a/include/standard-headers/asm-x86/bootparam.h b/include/standard-headers/asm-x86/bootparam.h > index 072e2ed546..b2aaad10e5 100644 > --- a/include/standard-headers/asm-x86/bootparam.h > +++ b/include/standard-headers/asm-x86/bootparam.h > @@ -10,6 +10,7 @@ > #define SETUP_EFI 4 > #define SETUP_APPLE_PROPERTIES 5 > #define SETUP_JAILHOUSE 6 > +#define SETUP_RNG_SEED 9 > > #define SETUP_INDIRECT (1<<31) > > -- > 2.35.1