From patchwork Mon Oct 3 13:10:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thadeu Lima de Souza Cascardo X-Patchwork-Id: 12997559 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CFA04C4332F for ; Mon, 3 Oct 2022 13:12:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230030AbiJCNMO (ORCPT ); Mon, 3 Oct 2022 09:12:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59820 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230023AbiJCNML (ORCPT ); Mon, 3 Oct 2022 09:12:11 -0400 Received: from smtp-relay-canonical-1.canonical.com (smtp-relay-canonical-1.canonical.com [185.125.188.121]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1E49D4DB73; Mon, 3 Oct 2022 06:11:59 -0700 (PDT) Received: from quatroqueijos.. (unknown [179.93.174.77]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by smtp-relay-canonical-1.canonical.com (Postfix) with ESMTPSA id 4ECBD42FBA; Mon, 3 Oct 2022 13:11:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=canonical.com; s=20210705; t=1664802708; bh=oaPLx/JBTDZUAuDRzH79S+RRrmNRbo71bcb9Yb6LapU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=j1wzo7SVqvmCar3YQFCis3JBxdN/DcNFN2fhUffuXyR1mtV633t+pCRjmAZB7qfHR 1NvzjvHfX7tzFvhfB/7JiqZgjHLJAevmx3jtCOs5KRRmPsKPHugkeen69/eO+diYrU KIU8HIlurzVz6A/tlTxmQL2D0oSHjdxqK8LrRzZwPBGRVQn92sVlCvnVq7FSy37MVg aBJ5nJgppIljN3vnGczXk4dREdlBoTi8rt6V4bXk2MknF+0EPLQP4USaioOOe+N2+Z A3a1K7nx/IuzV/rCi96FyI0uoy/cQCkZHscHW0IBgGR/vLW6E+NvmITR6HC+iiYFy2 FPzWh8gyRzhcg== From: Thadeu Lima de Souza Cascardo To: stable@vger.kernel.org Cc: x86@kernel.org, kvm@vger.kernel.org, bp@alien8.de, pbonzini@redhat.com, peterz@infradead.org, jpoimboe@kernel.org Subject: [PATCH 5.4 15/37] x86/bugs: Split spectre_v2_select_mitigation() and spectre_v2_user_select_mitigation() Date: Mon, 3 Oct 2022 10:10:16 -0300 Message-Id: <20221003131038.12645-16-cascardo@canonical.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20221003131038.12645-1-cascardo@canonical.com> References: <20221003131038.12645-1-cascardo@canonical.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Peter Zijlstra commit 166115c08a9b0b846b783088808a27d739be6e8d upstream. retbleed will depend on spectre_v2, while spectre_v2_user depends on retbleed. Break this cycle. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov Reviewed-by: Josh Poimboeuf Signed-off-by: Borislav Petkov Signed-off-by: Thadeu Lima de Souza Cascardo --- arch/x86/kernel/cpu/bugs.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 497562e78876..74f81db13585 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -36,8 +36,9 @@ #include "cpu.h" static void __init spectre_v1_select_mitigation(void); -static void __init retbleed_select_mitigation(void); static void __init spectre_v2_select_mitigation(void); +static void __init retbleed_select_mitigation(void); +static void __init spectre_v2_user_select_mitigation(void); static void __init ssb_select_mitigation(void); static void __init l1tf_select_mitigation(void); static void __init mds_select_mitigation(void); @@ -136,13 +137,19 @@ void __init check_bugs(void) /* Select the proper CPU mitigations before patching alternatives: */ spectre_v1_select_mitigation(); + spectre_v2_select_mitigation(); + /* + * retbleed_select_mitigation() relies on the state set by + * spectre_v2_select_mitigation(); specifically it wants to know about + * spectre_v2=ibrs. + */ retbleed_select_mitigation(); /* - * spectre_v2_select_mitigation() relies on the state set by + * spectre_v2_user_select_mitigation() relies on the state set by * retbleed_select_mitigation(); specifically the STIBP selection is * forced for UNRET. */ - spectre_v2_select_mitigation(); + spectre_v2_user_select_mitigation(); ssb_select_mitigation(); l1tf_select_mitigation(); md_clear_select_mitigation(); @@ -918,13 +925,15 @@ static void __init spec_v2_user_print_cond(const char *reason, bool secure) pr_info("spectre_v2_user=%s forced on command line.\n", reason); } +static __ro_after_init enum spectre_v2_mitigation_cmd spectre_v2_cmd; + static enum spectre_v2_user_cmd __init -spectre_v2_parse_user_cmdline(enum spectre_v2_mitigation_cmd v2_cmd) +spectre_v2_parse_user_cmdline(void) { char arg[20]; int ret, i; - switch (v2_cmd) { + switch (spectre_v2_cmd) { case SPECTRE_V2_CMD_NONE: return SPECTRE_V2_USER_CMD_NONE; case SPECTRE_V2_CMD_FORCE: @@ -959,7 +968,7 @@ static inline bool spectre_v2_in_ibrs_mode(enum spectre_v2_mitigation mode) } static void __init -spectre_v2_user_select_mitigation(enum spectre_v2_mitigation_cmd v2_cmd) +spectre_v2_user_select_mitigation(void) { enum spectre_v2_user_mitigation mode = SPECTRE_V2_USER_NONE; bool smt_possible = IS_ENABLED(CONFIG_SMP); @@ -972,7 +981,7 @@ spectre_v2_user_select_mitigation(enum spectre_v2_mitigation_cmd v2_cmd) cpu_smt_control == CPU_SMT_NOT_SUPPORTED) smt_possible = false; - cmd = spectre_v2_parse_user_cmdline(v2_cmd); + cmd = spectre_v2_parse_user_cmdline(); switch (cmd) { case SPECTRE_V2_USER_CMD_NONE: goto set_mode; @@ -1289,7 +1298,7 @@ static void __init spectre_v2_select_mitigation(void) } /* Set up IBPB and STIBP depending on the general spectre V2 command */ - spectre_v2_user_select_mitigation(cmd); + spectre_v2_cmd = cmd; } static void update_stibp_msr(void * __unused)