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=-14.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 EFD6EC4338F for ; Wed, 18 Aug 2021 11:13:04 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 6C51E6108F for ; Wed, 18 Aug 2021 11:13:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 6C51E6108F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id E817A4B086; Wed, 18 Aug 2021 07:13:03 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ZW43L8JiuvZW; Wed, 18 Aug 2021 07:12:59 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 319F14B097; Wed, 18 Aug 2021 07:12:59 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id BBCF04B086 for ; Wed, 18 Aug 2021 07:12:57 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ToQpmcrUlfEE for ; Wed, 18 Aug 2021 07:12:56 -0400 (EDT) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 92CC94A2E5 for ; Wed, 18 Aug 2021 07:12:56 -0400 (EDT) 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 6ADD06108F; Wed, 18 Aug 2021 11:12:55 +0000 (UTC) Received: from sofa.misterjones.org ([185.219.108.64] helo=why.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1mGJV6-005jgS-V1; Wed, 18 Aug 2021 12:12:53 +0100 Date: Wed, 18 Aug 2021 12:12:52 +0100 Message-ID: <87pmubrop7.wl-maz@kernel.org> From: Marc Zyngier To: Oliver Upton Subject: Re: [PATCH 3/4] KVM: arm64: Enforce reserved bits for PSCI target affinities In-Reply-To: <20210818085047.1005285-4-oupton@google.com> References: <20210818085047.1005285-1-oupton@google.com> <20210818085047.1005285-4-oupton@google.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: oupton@google.com, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, pshier@google.com, ricarkol@google.com, jingzhangos@google.com, rananta@google.com, james.morse@arm.com, alexandru.elisei@arm.com, suzuki.poulose@arm.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Cc: kvm@vger.kernel.org, Peter Shier , Raghavendra Rao Anata , kvmarm@lists.cs.columbia.edu X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Wed, 18 Aug 2021 09:50:46 +0100, Oliver Upton wrote: > > Some calls in PSCI take a target affinity argument, defined to be > bit-compatible with the affinity fields in MPIDR_EL1. All other bits in > the parameter are reserved and must be 0. For future reference, it may be worth quoting the spec (ARM DEN 0022D, 5.1.4 "CPU_ON"). > Return INVALID_PARAMETERS if the guest incorrectly sets a reserved > bit. > > Signed-off-by: Oliver Upton > --- > arch/arm64/kvm/psci.c | 20 +++++++++++++++++--- > 1 file changed, 17 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c > index db4056ecccfd..bb76be01abd2 100644 > --- a/arch/arm64/kvm/psci.c > +++ b/arch/arm64/kvm/psci.c > @@ -59,6 +59,17 @@ static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu) > kvm_vcpu_kick(vcpu); > } > > +static inline bool kvm_psci_valid_affinity(struct kvm_vcpu *vcpu, > + unsigned long affinity) > +{ > + unsigned long mask = MPIDR_HWID_BITMASK; > + > + if (vcpu_mode_is_32bit(vcpu)) > + mask &= ~((u32) 0); I don't think we need this anymore since 5.7: - fdc9999e20cd ("KVM: arm64: PSCI: Forbid 64bit functions for 32bit guests") guarantees that the guest can't trick KVM into using the SMC64 functions. - with 2890ac993daa ("KVM: arm64: PSCI: Narrow input registers when using 32bit functions"), the registers are always narrowed down to 32bit Put the two together, and you can't have a 32bit guest issuing a PSCI operation with crap in the upper 32bits. > + > + return !(affinity & ~mask); So the whole helper can now be rewritten as return !(affinity & ~MPIDR_HWID_BITMASK); > +} > + > static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu) > { > struct vcpu_reset_state *reset_state; > @@ -66,9 +77,9 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu) > struct kvm_vcpu *vcpu = NULL; > unsigned long cpu_id; > > - cpu_id = smccc_get_arg1(source_vcpu) & MPIDR_HWID_BITMASK; > - if (vcpu_mode_is_32bit(source_vcpu)) > - cpu_id &= ~((u32) 0); > + cpu_id = smccc_get_arg1(source_vcpu); > + if (!kvm_psci_valid_affinity(source_vcpu, cpu_id)) > + return PSCI_RET_INVALID_PARAMS; > > vcpu = kvm_mpidr_to_vcpu(kvm, cpu_id); > > @@ -126,6 +137,9 @@ static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu) > target_affinity = smccc_get_arg1(vcpu); > lowest_affinity_level = smccc_get_arg2(vcpu); > > + if (!kvm_psci_valid_affinity(vcpu, target_affinity)) > + return PSCI_RET_INVALID_PARAMS; > + > /* Determine target affinity mask */ > target_affinity_mask = psci_affinity_mask(lowest_affinity_level); > if (!target_affinity_mask) Otherwise, looks good to me. Thanks, M. -- Without deviation from the norm, progress is not possible. _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm