From patchwork Fri Nov 27 11:21:01 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 11935565 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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 70ECDC64E8A for ; Fri, 27 Nov 2020 11:21:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 174A820B80 for ; Fri, 27 Nov 2020 11:21:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="H63Vu6qu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729506AbgK0LVZ (ORCPT ); Fri, 27 Nov 2020 06:21:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:54932 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729416AbgK0LVX (ORCPT ); Fri, 27 Nov 2020 06:21:23 -0500 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 EAE8521973; Fri, 27 Nov 2020 11:21:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1606476082; bh=PewcZ0rzrlxCPatqpFVI8s3T+tQgk8XqSu8BrcC/ilQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=H63Vu6qusRwErPgOfLpBLFRWoEte988yFNickgfvXC+IYjUnhqYu7DvOU2urmnqNK nlFK/wdYkQg1aHaZ2dWReYE/eN+BYg/v9r+vZdxIPv57goM4FM/HSaAbi6XBBwct25 OIloVfJMIjMAvooAdKZUsIqBbdIEFPg06MnWpeOA= 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 1kiboW-00E2fR-4z; Fri, 27 Nov 2020 11:21:20 +0000 From: Marc Zyngier To: Paolo Bonzini Cc: David Brazdil , Eric Auger , Jamie Iles , Keqian Zhu , Will Deacon , Zenghui Yu , James Morse , Julien Thierry , Suzuki K Poulose , kernel-team@android.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH 2/2] KVM: arm64: vgic-v3: Drop the reporting of GICR_TYPER.Last for userspace Date: Fri, 27 Nov 2020 11:21:01 +0000 Message-Id: <20201127112101.658224-3-maz@kernel.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201127112101.658224-1-maz@kernel.org> References: <20201127112101.658224-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: pbonzini@redhat.com, dbrazdil@google.com, eric.auger@redhat.com, jamie@nuviainc.com, zhukeqian1@huawei.com, will@kernel.org, yuzenghui@huawei.com, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, kernel-team@android.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, stable@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Zenghui Yu It was recently reported that if GICR_TYPER is accessed before the RD base address is set, we'll suffer from the unset @rdreg dereferencing. Oops... gpa_t last_rdist_typer = rdreg->base + GICR_TYPER + (rdreg->free_index - 1) * KVM_VGIC_V3_REDIST_SIZE; It's "expected" that users will access registers in the redistributor if the RD has been properly configured (e.g., the RD base address is set). But it hasn't yet been covered by the existing documentation. Per discussion on the list [1], the reporting of the GICR_TYPER.Last bit for userspace never actually worked. And it's difficult for us to emulate it correctly given that userspace has the flexibility to access it any time. Let's just drop the reporting of the Last bit for userspace for now (userspace should have full knowledge about it anyway) and it at least prevents kernel from panic ;-) [1] https://lore.kernel.org/kvmarm/c20865a267e44d1e2c0d52ce4e012263@kernel.org/ Fixes: ba7b3f1275fd ("KVM: arm/arm64: Revisit Redistributor TYPER last bit computation") Reported-by: Keqian Zhu Signed-off-by: Zenghui Yu Signed-off-by: Marc Zyngier Reviewed-by: Eric Auger Link: https://lore.kernel.org/r/20201117151629.1738-1-yuzenghui@huawei.com Cc: stable@vger.kernel.org --- arch/arm64/kvm/vgic/vgic-mmio-v3.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c index 52d6f24f65dc..15a6c98ee92f 100644 --- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c +++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c @@ -273,6 +273,23 @@ static unsigned long vgic_mmio_read_v3r_typer(struct kvm_vcpu *vcpu, return extract_bytes(value, addr & 7, len); } +static unsigned long vgic_uaccess_read_v3r_typer(struct kvm_vcpu *vcpu, + gpa_t addr, unsigned int len) +{ + unsigned long mpidr = kvm_vcpu_get_mpidr_aff(vcpu); + int target_vcpu_id = vcpu->vcpu_id; + u64 value; + + value = (u64)(mpidr & GENMASK(23, 0)) << 32; + value |= ((target_vcpu_id & 0xffff) << 8); + + if (vgic_has_its(vcpu->kvm)) + value |= GICR_TYPER_PLPIS; + + /* reporting of the Last bit is not supported for userspace */ + return extract_bytes(value, addr & 7, len); +} + static unsigned long vgic_mmio_read_v3r_iidr(struct kvm_vcpu *vcpu, gpa_t addr, unsigned int len) { @@ -593,8 +610,9 @@ static const struct vgic_register_region vgic_v3_rd_registers[] = { REGISTER_DESC_WITH_LENGTH(GICR_IIDR, vgic_mmio_read_v3r_iidr, vgic_mmio_write_wi, 4, VGIC_ACCESS_32bit), - REGISTER_DESC_WITH_LENGTH(GICR_TYPER, - vgic_mmio_read_v3r_typer, vgic_mmio_write_wi, 8, + REGISTER_DESC_WITH_LENGTH_UACCESS(GICR_TYPER, + vgic_mmio_read_v3r_typer, vgic_mmio_write_wi, + vgic_uaccess_read_v3r_typer, vgic_mmio_uaccess_write_wi, 8, VGIC_ACCESS_64bit | VGIC_ACCESS_32bit), REGISTER_DESC_WITH_LENGTH(GICR_WAKER, vgic_mmio_read_raz, vgic_mmio_write_wi, 4,