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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 36383C433B4 for ; Thu, 15 Apr 2021 15:01:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0FFC961152 for ; Thu, 15 Apr 2021 15:01:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234085AbhDOPBh (ORCPT ); Thu, 15 Apr 2021 11:01:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:46754 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234431AbhDOO6f (ORCPT ); Thu, 15 Apr 2021 10:58:35 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0D83F613D7; Thu, 15 Apr 2021 14:54:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1618498500; bh=dWdpBlt/F8Ey2+xsNIcXAu7JRQ3UrZYAdUFlHh9MDtw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=H9W7HYo3IM3OePAbFzctQ8l2ep+3Cf2Gw32szGKeXSYmC8IudWLx0FPzZrufyaUHr pJzt5JlNsn4GH/oRO0dCUWi56gp+NiWnwHXH3ys6b4DSs7cjGDqGt+QOItCJy9h4nz ZhsNaYgpP+202Gv3/LqN6KE8STk6ieVQgab72BSU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Will Deacon , Catalin Marinas , Mark Rutland , Suzuki K Poulose , Marc Zyngier , Sasha Levin Subject: [PATCH 4.14 60/68] KVM: arm64: Hide system instruction access to Trace registers Date: Thu, 15 Apr 2021 16:47:41 +0200 Message-Id: <20210415144416.440816817@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210415144414.464797272@linuxfoundation.org> References: <20210415144414.464797272@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Suzuki K Poulose [ Upstream commit 1d676673d665fd2162e7e466dcfbe5373bfdb73e ] Currently we advertise the ID_AA6DFR0_EL1.TRACEVER for the guest, when the trace register accesses are trapped (CPTR_EL2.TTA == 1). So, the guest will get an undefined instruction, if trusts the ID registers and access one of the trace registers. Lets be nice to the guest and hide the feature to avoid unexpected behavior. Even though this can be done at KVM sysreg emulation layer, we do this by removing the TRACEVER from the sanitised feature register field. This is fine as long as the ETM drivers can handle the individual trace units separately, even when there are differences among the CPUs. Cc: Will Deacon Cc: Catalin Marinas Cc: Mark Rutland Signed-off-by: Suzuki K Poulose Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20210323120647.454211-2-suzuki.poulose@arm.com Signed-off-by: Sasha Levin --- arch/arm64/kernel/cpufeature.c | 1 - 1 file changed, 1 deletion(-) diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 174aa12fb8b1..1481e18aa5ca 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -230,7 +230,6 @@ static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = { * of support. */ S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_AA64DFR0_PMUVER_SHIFT, 4, 0), - ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64DFR0_TRACEVER_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64DFR0_DEBUGVER_SHIFT, 4, 0x6), ARM64_FTR_END, }; -- 2.30.2