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,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 22DDCC43600 for ; Thu, 15 Apr 2021 15:09:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 12568613D8 for ; Thu, 15 Apr 2021 15:09:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235264AbhDOPJO (ORCPT ); Thu, 15 Apr 2021 11:09:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:45872 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235104AbhDOPAW (ORCPT ); Thu, 15 Apr 2021 11:00:22 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 374896140A; Thu, 15 Apr 2021 14:56:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1618498583; bh=mIpMHbgtarwGrt6vg+yVjTI4jWbgZVAP5Q+APwJgb44=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SlMPwM6Qn5OxbvZuj9b9eCARZ0cXQsCrTh/dsBZbjZbfYN3UI1hSxidXpWs+NRWU6 gGFlzL0YWTEx49fSy2VxJlknNocGomGQSCAPkL1ZyS3Q+dq+8D7CV9dZ3qpM+Oqv9B fgVhab8oRlyvlinklbxkTf9wlzBof/Q6qqcKNw6o= 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 5.4 02/18] KVM: arm64: Hide system instruction access to Trace registers Date: Thu, 15 Apr 2021 16:47:55 +0200 Message-Id: <20210415144413.132401786@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210415144413.055232956@linuxfoundation.org> References: <20210415144413.055232956@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: linux-kernel@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 79caab15ccbf..acdef8d76c64 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -277,7 +277,6 @@ 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