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 7DDCEC4332F for ; Fri, 30 Sep 2022 15:09:18 +0000 (UTC) Received: from localhost ([::1]:58476 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oeHdd-00034Q-DT for qemu-devel@archiver.kernel.org; Fri, 30 Sep 2022 11:09:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42164) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oeHZs-0001IX-Ob for qemu-devel@nongnu.org; Fri, 30 Sep 2022 11:05:24 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:49996) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oeHZo-0005Eg-Hy for qemu-devel@nongnu.org; Fri, 30 Sep 2022 11:05:22 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1664550315; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=slo+eMUZtKq1RID7CDn8DE2h5hJ2Jw9pXsl0GddModw=; b=jCn+5TFvVGgzrQw1ujFfaN9WEmHCjcQKmRxLTUxBZeReARIxhLR6HgQpXW3ON1QbVsgS3A M9Pq/+A0DSqgi7EwlgmymmOAAyvSLeusr8VdJ242n6FCvF44QFI2nsAaDgvZX2fDMDOHpR FvWj55rYySeIDAxo2rzJ/k76ngueS1Q= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-520-_rrRESY1PrylNvG2JslnFQ-1; Fri, 30 Sep 2022 11:05:13 -0400 X-MC-Unique: _rrRESY1PrylNvG2JslnFQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 209BD1C05AF5; Fri, 30 Sep 2022 15:05:13 +0000 (UTC) Received: from redhat.com (unknown [10.33.36.77]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E7977111E3FB; Fri, 30 Sep 2022 15:05:11 +0000 (UTC) Date: Fri, 30 Sep 2022 16:05:09 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: "Jason A. Donenfeld" Cc: f4bug@amsat.org, aurelien@aurel32.net, qemu-devel@nongnu.org, tsbogend@alpha.franken.de Subject: Re: [PATCH qemu] mips/malta: pass RNG seed to to kernel via env var Message-ID: References: <20220930140520.576374-1-Jason@zx2c4.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220930140520.576374-1-Jason@zx2c4.com> User-Agent: Mutt/2.2.7 (2022-08-07) X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@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 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, Sep 30, 2022 at 04:05:20PM +0200, Jason A. Donenfeld wrote: > With the kernel patch linked below, Linux ingests a RNG seed > passed from the hypervisor. So, pass this for the Malta platform, and > reinitialize it on reboot too, so that it's always fresh. > > Link: https://lore.kernel.org/linux-mips/20220930140138.575751-1-Jason@zx2c4.com/ > Signed-off-by: Jason A. Donenfeld > --- > hw/mips/malta.c | 25 +++++++++++++++++++++++++ > 1 file changed, 25 insertions(+) > > diff --git a/hw/mips/malta.c b/hw/mips/malta.c > index 0e932988e0..9d793b3c17 100644 > --- a/hw/mips/malta.c > +++ b/hw/mips/malta.c > @@ -26,6 +26,7 @@ > #include "qemu/units.h" > #include "qemu/bitops.h" > #include "qemu/datadir.h" > +#include "qemu/guest-random.h" > #include "hw/clock.h" > #include "hw/southbridge/piix.h" > #include "hw/isa/superio.h" > @@ -1017,6 +1018,17 @@ static void G_GNUC_PRINTF(3, 4) prom_set(uint32_t *prom_buf, int index, > va_end(ap); > } > > +static void reinitialize_rng_seed(void *opaque) > +{ > + char *rng_seed_hex = opaque; > + uint8_t rng_seed[32]; > + > + qemu_guest_getrandom_nofail(rng_seed, sizeof(rng_seed)); > + for (size_t i = 0; i < sizeof(rng_seed); ++i) { > + sprintf(rng_seed_hex + i * 2, "%02x", rng_seed[i]); > + } > +} > + > /* Kernel */ > static uint64_t load_kernel(void) > { > @@ -1028,6 +1040,8 @@ static uint64_t load_kernel(void) > long prom_size; > int prom_index = 0; > uint64_t (*xlate_to_kseg0) (void *opaque, uint64_t addr); > + uint8_t rng_seed[32]; > + char rng_seed_hex[sizeof(rng_seed) * 2 + 1]; The +1 suggests you're intending to NUL terminate, but nothing in this patch ever initializes this last byte. > > #if TARGET_BIG_ENDIAN > big_endian = 1; > @@ -1115,9 +1129,20 @@ static uint64_t load_kernel(void) > > prom_set(prom_buf, prom_index++, "modetty0"); > prom_set(prom_buf, prom_index++, "38400n8r"); > + > + qemu_guest_getrandom_nofail(rng_seed, sizeof(rng_seed)); > + for (size_t i = 0; i < sizeof(rng_seed); ++i) { > + sprintf(rng_seed_hex + i * 2, "%02x", rng_seed[i]); > + } > + prom_set(prom_buf, prom_index++, "rngseed"); > + prom_set(prom_buf, prom_index++, "%s", rng_seed_hex); > + > prom_set(prom_buf, prom_index++, NULL); > > rom_add_blob_fixed("prom", prom_buf, prom_size, ENVP_PADDR); > + qemu_register_reset(reinitialize_rng_seed, > + memmem(rom_ptr(ENVP_PADDR, prom_size), prom_size, > + rng_seed_hex, sizeof(rng_seed_hex))); > > g_free(prom_buf); > return kernel_entry; > -- > 2.37.3 > > With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|