From nobody Fri Nov 22 02:24:38 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=pass(p=reject dis=none) header.from=citrix.com ARC-Seal: i=1; a=rsa-sha256; t=1730107176; cv=none; d=zohomail.com; s=zohoarc; b=eoPujis94hXGbiblC5HlwYjBOiN20ee5otFkBvYytGAc07/L/yUwJm6/EHyJmFysNSFuufatLrqfwQ/4/zx7M4sCzHobzT6Z63BiSAG6HUDaTkr7dkYWyuEYG/E8m8OukuuaRJwdCApO76yXsYi4f36XShTH3lDA9fHN7jrZ7uU= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1730107176; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=2tHJ9KvrKOuMjaRdKbRkR2CwfZwErwPkHq08Lc76WTw=; b=YtSxcLF2T3GOODLyhhw7aIo5PdnSDE04c9P0e8mRMB/sN2Vzub1pbvgjQyi3Bd59NdA1RVRd/hc6rzW1bHT6tDpiSgWgvIOYsYJj4ldAc8xOq4NTlDHBkfj0INxgZQVrs+sgjrI5T6/rhWL6B0Vuw0usXguQZzy9Kq2fGHoWyfQ= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=pass header.from= (p=reject dis=none) Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1730107176278225.90371266170484; Mon, 28 Oct 2024 02:19:36 -0700 (PDT) Received: from list by lists.xenproject.org with outflank-mailman.826299.1240541 (Exim 4.92) (envelope-from ) id 1t5Lu5-0006gx-3V; Mon, 28 Oct 2024 09:19:13 +0000 Received: by outflank-mailman (output) from mailman id 826299.1240541; Mon, 28 Oct 2024 09:19:13 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1t5Lu4-0006fH-TX; Mon, 28 Oct 2024 09:19:12 +0000 Received: by outflank-mailman (input) for mailman id 826299; Mon, 28 Oct 2024 09:19:11 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1t5Lu3-0005MP-DJ for xen-devel@lists.xenproject.org; Mon, 28 Oct 2024 09:19:11 +0000 Received: from mail-ej1-x634.google.com (mail-ej1-x634.google.com [2a00:1450:4864:20::634]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id b0d03caf-950d-11ef-a0c2-8be0dac302b0; Mon, 28 Oct 2024 10:19:10 +0100 (CET) Received: by mail-ej1-x634.google.com with SMTP id a640c23a62f3a-a9a6b4ca29bso503388266b.3 for ; Mon, 28 Oct 2024 02:19:10 -0700 (PDT) Received: from andrewcoop.eng.citrite.net ([185.25.67.249]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a9b1f05deb6sm355961566b.88.2024.10.28.02.19.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 28 Oct 2024 02:19:08 -0700 (PDT) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: b0d03caf-950d-11ef-a0c2-8be0dac302b0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.com; s=google; t=1730107150; x=1730711950; darn=lists.xenproject.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=2tHJ9KvrKOuMjaRdKbRkR2CwfZwErwPkHq08Lc76WTw=; b=kahqWksxgzonAQz1hLCbU2S8FFI6DVKIeBrsa/xBMnrbV6FIhTxLUjFO4yymZr934T Fwp22CxvtECXf/VLMk8ogr5zoBKk5DmtUg2ZodOU/978FSgLVwSPT6Heg7y6iPJhmp29 jFIgRRJfO2m9NepiFzsdXGbrGZHP+zQIPS0+E= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1730107150; x=1730711950; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=2tHJ9KvrKOuMjaRdKbRkR2CwfZwErwPkHq08Lc76WTw=; b=Gt6d52xzOfaHgt9I9Itrm4BN+Ka8bSBhSbPtaPLAeOKxmIl9FQO3b0PzDVUJdOjQSa YPPelV3ASAAm8UpWyIQ2Ydxio9rA/WNF6sW9xGDK2Apmow7nRIkHBpIavkdTnR1FMctc 2aCxwWnmdg2YZZcFigOLDWxM45mW09V47gjI7ypBEzM2nC17vhp3C/4dbL/kTaqgoAP3 uGyQqbPzqUw4OXal5O9W/l5HJirpt2cKyg3HggiWt8TLX8tkfg/th5eMLVwbpn8f9Jo2 buGOPl+H/KMPpvGlHRhxT/vBCyXw+38OlhFKM9PAxUE8fe0D6funn3dV2ZwrYILE+BPx 2ULQ== X-Gm-Message-State: AOJu0YxDKyiUAKffccbHTWHC40TxlqyYM06ZyqCO5WgIWuwxnmBYZOWj Jo6johjfjQ/Y9SCm/pu6GlUuZ3/b+4R5/pljLh3G4gBvPASHBqmjyFTkLh5IgI+2maydO7sWaxv L X-Google-Smtp-Source: AGHT+IFnmPuo6iIDZ2uIcOkFOtwk+936hL3j8xHD3pymnaePQ9S+o2bupb6g8N/5ycChEVRj6IpzKg== X-Received: by 2002:a17:907:3f20:b0:a9a:375e:c167 with SMTP id a640c23a62f3a-a9de5c91a19mr711781366b.1.1730107149626; Mon, 28 Oct 2024 02:19:09 -0700 (PDT) From: Andrew Cooper To: Xen-devel Cc: Andrew Cooper , Jan Beulich , =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= , "Daniel P . Smith" Subject: [PATCH 06/10] x86/ucode: Enforce invariant about module selection Date: Mon, 28 Oct 2024 09:18:52 +0000 Message-Id: <20241028091856.2151603-7-andrew.cooper3@citrix.com> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20241028091856.2151603-1-andrew.cooper3@citrix.com> References: <20241028091856.2151603-1-andrew.cooper3@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @citrix.com) X-ZM-MESSAGEID: 1730107177374116600 The work to add the `ucode=3Dnmi` cmdline option left a subtle corner case. Both scan and an explicit index could be selected, and we could really find= a CPIO archive and explicit microcode file. Worse, because the if/else chains for processing ucode_{blob,mod} are oppos= ite ways around in early_microcode_load() and microcode_init_cache(), we can genuinely perform early microcode loading from the CPIO archive, then cache from the explicit file. Therefore, enforce that only one selection method can be active. Rename ucode_{scan,mod_idx} to have an opt_ prefix. This is both for consistency with the rest of Xen, and to guarantee that we've got all instances of the variables covered in this change. Explain how they're use. During cmdline/config parsing, always update both variables in pairs. In early_microcode_load(), ASSERT() the invariant just in case. Use a local variable for idx rather than operating on the static; we're the only consume of the value. Expand the index selection logic with comments and warnings to the user when something went wrong. Fixes: 5ed12565aa32 ("microcode: rendezvous CPUs in NMI handler and load uc= ode") Signed-off-by: Andrew Cooper Reviewed-by: Daniel P. Smith --- CC: Jan Beulich CC: Roger Pau Monn=C3=A9 CC: Daniel P. Smith Despite the fixes tag, this can't be backported (at least not in this form). --- xen/arch/x86/cpu/microcode/core.c | 76 +++++++++++++++++++++++-------- 1 file changed, 57 insertions(+), 19 deletions(-) diff --git a/xen/arch/x86/cpu/microcode/core.c b/xen/arch/x86/cpu/microcode= /core.c index 4c4003bf9687..fc31ab35c3c8 100644 --- a/xen/arch/x86/cpu/microcode/core.c +++ b/xen/arch/x86/cpu/microcode/core.c @@ -60,7 +60,6 @@ #define MICROCODE_UPDATE_TIMEOUT_US 1000000 =20 static module_t __initdata ucode_mod; -static signed int __initdata ucode_mod_idx; static bool __initdata ucode_mod_forced; static unsigned int nr_cores; =20 @@ -97,11 +96,6 @@ struct patch_with_flags { }; =20 static struct ucode_mod_blob __initdata ucode_blob; -/* - * By default we will NOT parse the multiboot modules to see if there is - * cpio image with the microcode images. - */ -static bool __initdata ucode_scan; =20 /* By default, ucode loading is done in NMI handler */ static bool ucode_in_nmi =3D true; @@ -109,13 +103,28 @@ static bool ucode_in_nmi =3D true; /* Protected by microcode_mutex */ static const struct microcode_patch *microcode_cache; =20 +/* + * opt_mod_idx and opt_scan have subtle semantics. + * + * The cmdline can either identify a module by number (inc -ve back-refere= nce) + * containing a raw microcode container, or select scan which instructs Xe= n to + * search all modules for an uncompressed CPIO archive containing a file w= ith + * a vendor-dependent name. + * + * These options do not make sense when combined, so for the benefit of mo= dule + * location we require that they are not both active together. + */ +static int __initdata opt_mod_idx; +static bool __initdata opt_scan; + /* * Used by the EFI path only, when xen.cfg identifies an explicit microcode * file. Overrides ucode=3D|scan on the regular command line. */ void __init microcode_set_module(unsigned int idx) { - ucode_mod_idx =3D idx; + opt_mod_idx =3D idx; + opt_scan =3D false; ucode_mod_forced =3D 1; } =20 @@ -139,12 +148,16 @@ static int __init cf_check parse_ucode(const char *s) else if ( !ucode_mod_forced ) /* Not forced by EFI */ { if ( (val =3D parse_boolean("scan", s, ss)) >=3D 0 ) - ucode_scan =3D val; + { + opt_scan =3D val; + opt_mod_idx =3D 0; + } else { const char *q; =20 - ucode_mod_idx =3D simple_strtol(s, &q, 0); + opt_scan =3D false; + opt_mod_idx =3D simple_strtol(s, &q, 0); if ( q !=3D ss ) rc =3D -EINVAL; } @@ -166,7 +179,7 @@ static void __init microcode_scan_module(struct boot_in= fo *bi) int i; =20 ucode_blob.size =3D 0; - if ( !ucode_scan ) + if ( !opt_scan ) return; =20 if ( boot_cpu_data.x86_vendor =3D=3D X86_VENDOR_AMD ) @@ -792,7 +805,7 @@ static int __init cf_check microcode_init_cache(void) if ( !ucode_ops.apply_microcode ) return -ENODEV; =20 - if ( ucode_scan ) + if ( opt_scan ) /* Need to rescan the modules because they might have been relocat= ed */ microcode_scan_module(bi); =20 @@ -817,17 +830,42 @@ static int __init early_microcode_load(struct boot_in= fo *bi) const void *data =3D NULL; size_t size; struct microcode_patch *patch; + int idx =3D opt_mod_idx; + + /* + * Cmdline parsing ensures this invariant holds, so that we don't end = up + * trying to mix multiple ways of finding the microcode. + */ + ASSERT(idx =3D=3D 0 || !opt_scan); =20 - if ( ucode_mod_idx < 0 ) - ucode_mod_idx +=3D bi->nr_modules; - if ( ucode_mod_idx <=3D 0 || ucode_mod_idx >=3D bi->nr_modules || - !__test_and_clear_bit(ucode_mod_idx, bi->module_map) ) - goto scan; - ucode_mod =3D *bi->mods[ucode_mod_idx].mod; - scan: - if ( ucode_scan ) + if ( opt_scan ) /* Scan for a CPIO archive */ microcode_scan_module(bi); =20 + if ( idx ) /* Specific module nominated */ + { + /* + * Negative indicies can be used to reference from the end of the + * modules. e.g. ucode=3D-1 refers to the last module. + */ + if ( idx < 0 ) + idx +=3D bi->nr_modules; + + if ( idx <=3D 0 || idx >=3D bi->nr_modules ) + { + printk(XENLOG_WARNING "Microcode: Chosen module %d out of rang= e [1, %u)\n", + idx, bi->nr_modules); + return -ENODEV; + } + + if ( !__test_and_clear_bit(idx, bi->module_map) ) + { + printk(XENLOG_WARNING "Microcode: Chosen module %d already use= d\n", idx); + return -ENODEV; + } + + ucode_mod =3D *bi->mods[idx].mod; + } + if ( !ucode_mod.mod_end && !ucode_blob.size ) return 0; =20 --=20 2.39.5