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=-17.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,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 3371FC433E0 for ; Thu, 7 Jan 2021 11:23:14 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 C6ECE208C3 for ; Thu, 7 Jan 2021 11:23:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C6ECE208C3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=qr8Lnz3kkFLW3LOk4gaUlJfWyhQlKVUtSdFB8oHLsrk=; b=OTNLcqVo82p+Uxa2InHtTdM+6 Lhmy07HTvtgAy2r8SLYSRI8h9pJkoAoyZQQQGTRvCnYWDjgkhQNWKWqUmTHhkn+RI88EFDzbsk9A0 F0x55bzAa0Hp9zzFvxTeGvG/KlGM3EDTLphoUPm8Ubr8zRzXL9n+xpEXOkTvbBZ+7jpo32pu+XlGP XgYC34GJGUengnk/NT8N+KzPm0sU/FPhezW89/ZtSmuhtOlxEfxP4f2yCliaKtGSAv2KGiilCSzxx AKAA5rIiT7XbNNR0mvf40pp7pFwgUTwc6xkQ0sVMm+xI2FhhcrgFNcAoAhRwEFQ+i/QdWdlzUJZ6S 06n0h4X5g==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kxTM8-0001ia-Ff; Thu, 07 Jan 2021 11:21:28 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kxTLz-0001eo-7x for linux-arm-kernel@lists.infradead.org; Thu, 07 Jan 2021 11:21:20 +0000 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7FFEE23125; Thu, 7 Jan 2021 11:21:18 +0000 (UTC) Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94) (envelope-from ) id 1kxTLw-005p1o-Nt; Thu, 07 Jan 2021 11:21:16 +0000 From: Marc Zyngier To: Paolo Bonzini Subject: [PATCH 01/18] KVM: arm64: Don't access PMCR_EL0 when no PMU is available Date: Thu, 7 Jan 2021 11:20:44 +0000 Message-Id: <20210107112101.2297944-2-maz@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210107112101.2297944-1-maz@kernel.org> References: <20210107112101.2297944-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: pbonzini@redhat.com, alexandru.elisei@arm.com, catalin.marinas@arm.com, dbrazdil@google.com, eric.auger@redhat.com, mark.rutland@arm.com, natechancellor@gmail.com, qcai@redhat.com, shannon.zhao@linux.alibaba.com, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, kernel-team@android.com, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210107_062119_373936_E51F2E4B X-CRM114-Status: GOOD ( 15.93 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , kernel-team@android.com, kvm@vger.kernel.org, Suzuki K Poulose , Qian Cai , Catalin Marinas , Shannon Zhao , Eric Auger , James Morse , linux-arm-kernel@lists.infradead.org, Nathan Chancellor , David Brazdil , Alexandru Elisei , kvmarm@lists.cs.columbia.edu, Julien Thierry Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org We reset the guest's view of PMCR_EL0 unconditionally, based on the host's view of this register. It is however legal for an implementation not to provide any PMU, resulting in an UNDEF. The obvious fix is to skip the reset of this shadow register when no PMU is available, sidestepping the issue entirely. If no PMU is available, the guest is not able to request a virtual PMU anyway, so not doing nothing is the right thing to do! It is unlikely that this bug can hit any HW implementation though, as they all provide a PMU. It has been found using nested virt with the host KVM not implementing the PMU itself. Fixes: ab9468340d2bc ("arm64: KVM: Add access handler for PMCR register") Reviewed-by: Alexandru Elisei Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20201210083059.1277162-1-maz@kernel.org --- arch/arm64/kvm/sys_regs.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 3313dedfa505..d46e7f706cb0 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -594,6 +594,10 @@ static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) { u64 pmcr, val; + /* No PMU available, PMCR_EL0 may UNDEF... */ + if (!kvm_arm_support_pmu_v3()) + return; + pmcr = read_sysreg(pmcr_el0); /* * Writable bits of PMCR_EL0 (ARMV8_PMU_PMCR_MASK) are reset to UNKNOWN -- 2.29.2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel