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 X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C813DC43331 for ; Tue, 31 Mar 2020 15:07:35 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A002520781 for ; Tue, 31 Mar 2020 15:07:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A002520781 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1jJITy-0002Ce-2Z; Tue, 31 Mar 2020 15:07:14 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1jJITw-0002CZ-Nj for xen-devel@lists.xenproject.org; Tue, 31 Mar 2020 15:07:12 +0000 X-Inumbo-ID: 4b8efeb6-7361-11ea-ba2a-12813bfff9fa Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 4b8efeb6-7361-11ea-ba2a-12813bfff9fa; Tue, 31 Mar 2020 15:07:11 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id EF78BAC22; Tue, 31 Mar 2020 15:07:09 +0000 (UTC) Subject: Re: [PATCH 11/11] x86/ucode/amd: Rework parsing logic in cpu_request_microcode() To: Andrew Cooper References: <20200331100531.4294-1-andrew.cooper3@citrix.com> <20200331100531.4294-12-andrew.cooper3@citrix.com> From: Jan Beulich Message-ID: Date: Tue, 31 Mar 2020 17:07:07 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200331100531.4294-12-andrew.cooper3@citrix.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Xen-devel , Wei Liu , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" On 31.03.2020 12:05, Andrew Cooper wrote: > @@ -269,55 +265,25 @@ static int apply_microcode(const struct microcode_patch *patch) > return 0; > } > > -static int scan_equiv_cpu_table( > - const void *data, > - size_t size_left, > - size_t *offset) > +static int scan_equiv_cpu_table(const struct container_equiv_table *et) > { > const struct cpu_signature *sig = &this_cpu(cpu_sig); > - const struct mpbhdr *mpbuf; > - const struct equiv_cpu_entry *eq; > - unsigned int i, nr; > - > - if ( size_left < (sizeof(*mpbuf) + 4) || > - (mpbuf = data + *offset + 4, > - size_left - sizeof(*mpbuf) - 4 < mpbuf->len) ) > - { > - printk(XENLOG_WARNING "microcode: No space for equivalent cpu table\n"); > - return -EINVAL; > - } > - > - *offset += mpbuf->len + CONT_HDR_SIZE; /* add header length */ > - > - if ( mpbuf->type != UCODE_EQUIV_CPU_TABLE_TYPE ) > - { > - printk(KERN_ERR "microcode: Wrong microcode equivalent cpu table type field\n"); > - return -EINVAL; > - } > - > - if ( mpbuf->len == 0 || mpbuf->len % sizeof(*eq) || > - (eq = (const void *)mpbuf->data, > - nr = mpbuf->len / sizeof(*eq), > - eq[nr - 1].installed_cpu) ) Did this last check get lost? I can't seem to be able to identify any possible replacement. > static struct microcode_patch *cpu_request_microcode(const void *buf, size_t size) > { > const struct microcode_patch *saved = NULL; > struct microcode_patch *patch = NULL; > - size_t offset = 0, saved_size = 0; > + size_t saved_size = 0; > int error = 0; > - unsigned int cpu = smp_processor_id(); > - const struct cpu_signature *sig = &per_cpu(cpu_sig, cpu); > > - if ( size < 4 || > - *(const uint32_t *)buf != UCODE_MAGIC ) > + while ( size ) > { > - printk(KERN_ERR "microcode: Wrong microcode patch file magic\n"); > - error = -EINVAL; > - goto out; > - } > - > - /* > - * Multiple container file support: > - * 1. check if this container file has equiv_cpu_id match > - * 2. If not, fast-fwd to next container file > - */ > - while ( offset < size ) > - { > - error = scan_equiv_cpu_table(buf, size - offset, &offset); > - > - if ( !error || error != -ESRCH ) > - break; > + const struct container_equiv_table *et; > + bool skip_ucode; > > - error = container_fast_forward(buf, size - offset, &offset); > - if ( error == -ENODATA ) > + if ( size < 4 || *(const uint32_t *)buf != UCODE_MAGIC ) > { > - ASSERT(offset == size); > + printk(XENLOG_ERR "microcode: Wrong microcode patch file magic\n"); > + error = -EINVAL; > break; > } > - if ( error ) > + > + /* Move over UCODE_MAGIC. */ > + buf += 4; > + size -= 4; > + > + if ( size < sizeof(*et) || > + (et = buf)->type != UCODE_EQUIV_CPU_TABLE_TYPE || > + size - sizeof(*et) < et->len || > + et->len % sizeof(et->eq[0]) ) > { > - printk(KERN_ERR "microcode: CPU%d incorrect or corrupt container file\n" > - "microcode: Failed to update patch level. " > - "Current lvl:%#x\n", cpu, sig->rev); > + printk(XENLOG_ERR "microcode: Bad equivalent cpu table\n"); > + error = -EINVAL; > break; > } > - } > > - if ( error ) > - { > - /* > - * -ENODATA here means that the blob was parsed fine but no matching > - * ucode was found. Don't return it to the caller. > - */ > - if ( error == -ENODATA ) > - error = 0; > - > - goto out; > - } > + /* Move over the Equiv table. */ > + buf += sizeof(*et) + et->len; > + size -= sizeof(*et) + et->len; > + > + error = scan_equiv_cpu_table(et); > + if ( error && error != -ESRCH ) > + break; With this the only non-zero value left for error is -ESRCH. Hence ... > + /* -ESRCH means no applicable microcode in this container. */ > + skip_ucode = error == -ESRCH; ... perhaps omit the "== -ESRCH" here, moving the comment up ahead of the if()? Jan