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=-9.0 required=3.0 tests=BAYES_00,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 52A6EC433E0 for ; Fri, 5 Feb 2021 20:12:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0197464FBA for ; Fri, 5 Feb 2021 20:12:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233193AbhBES3S (ORCPT ); Fri, 5 Feb 2021 13:29:18 -0500 Received: from mail.kernel.org ([198.145.29.99]:47308 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233152AbhBEPNJ (ORCPT ); Fri, 5 Feb 2021 10:13:09 -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 3AEB864EEB; Fri, 5 Feb 2021 16:50:30 +0000 (UTC) Received: from disco-boy.misterjones.org ([51.254.78.96] helo=www.loen.fr) by disco-boy.misterjones.org with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.94) (envelope-from ) id 1l84JP-00CIPY-Vb; Fri, 05 Feb 2021 16:50:28 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Fri, 05 Feb 2021 16:50:27 +0000 From: Marc Zyngier To: Will Deacon Cc: Steven Price , netdev@vger.kernel.org, yangbo.lu@nxp.com, john.stultz@linaro.org, tglx@linutronix.de, pbonzini@redhat.com, seanjc@google.com, richardcochran@gmail.com, Mark.Rutland@arm.com, suzuki.poulose@arm.com, Andre.Przywara@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Steve.Capper@arm.com, justin.he@arm.com, jianyong.wu@arm.com, kernel-team@android.com Subject: Re: [PATCH v17 1/7] arm/arm64: Probe for the presence of KVM hypervisor In-Reply-To: <20210205111921.GA22109@willie-the-truck> References: <20210202141204.3134855-1-maz@kernel.org> <20210202141204.3134855-2-maz@kernel.org> <20210205111921.GA22109@willie-the-truck> User-Agent: Roundcube Webmail/1.4.10 Message-ID: X-Sender: maz@kernel.org X-SA-Exim-Connect-IP: 51.254.78.96 X-SA-Exim-Rcpt-To: will@kernel.org, steven.price@arm.com, netdev@vger.kernel.org, yangbo.lu@nxp.com, john.stultz@linaro.org, tglx@linutronix.de, pbonzini@redhat.com, seanjc@google.com, richardcochran@gmail.com, Mark.Rutland@arm.com, suzuki.poulose@arm.com, Andre.Przywara@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Steve.Capper@arm.com, justin.he@arm.com, jianyong.wu@arm.com, kernel-team@android.com 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: netdev@vger.kernel.org On 2021-02-05 11:19, Will Deacon wrote: > On Fri, Feb 05, 2021 at 09:11:00AM +0000, Steven Price wrote: >> On 02/02/2021 14:11, Marc Zyngier wrote: >> > diff --git a/drivers/firmware/smccc/kvm_guest.c b/drivers/firmware/smccc/kvm_guest.c >> > new file mode 100644 >> > index 000000000000..23ce1ded88b4 >> > --- /dev/null >> > +++ b/drivers/firmware/smccc/kvm_guest.c >> > @@ -0,0 +1,51 @@ >> > +// SPDX-License-Identifier: GPL-2.0 >> > + >> > +#define pr_fmt(fmt) "smccc: KVM: " fmt >> > + >> > +#include >> > +#include >> > +#include >> > +#include >> > + >> > +static DECLARE_BITMAP(__kvm_arm_hyp_services, ARM_SMCCC_KVM_NUM_FUNCS) __ro_after_init = { }; >> > + >> > +void __init kvm_init_hyp_services(void) >> > +{ >> > + int i; >> > + struct arm_smccc_res res; >> > + >> > + if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_HVC) >> > + return; >> > + >> > + arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, &res); >> > + if (res.a0 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0 || >> > + res.a1 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1 || >> > + res.a2 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2 || >> > + res.a3 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3) >> > + return; >> > + >> > + memset(&res, 0, sizeof(res)); >> > + arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID, &res); >> > + for (i = 0; i < 32; ++i) { >> > + if (res.a0 & (i)) >> > + set_bit(i + (32 * 0), __kvm_arm_hyp_services); >> > + if (res.a1 & (i)) >> > + set_bit(i + (32 * 1), __kvm_arm_hyp_services); >> > + if (res.a2 & (i)) >> > + set_bit(i + (32 * 2), __kvm_arm_hyp_services); >> > + if (res.a3 & (i)) >> > + set_bit(i + (32 * 3), __kvm_arm_hyp_services); >> >> The bit shifts are missing, the tests should be of the form: >> >> if (res.a0 & (1 << i)) >> >> Or indeed using a BIT() macro. > > Maybe even test_bit()? Actually, maybe not doing things a-bit-at-a-time is less error prone. See below what I intend to fold in. Thanks, M. diff --git a/drivers/firmware/smccc/kvm_guest.c b/drivers/firmware/smccc/kvm_guest.c index 00bf3c7969fc..08836f2f39ee 100644 --- a/drivers/firmware/smccc/kvm_guest.c +++ b/drivers/firmware/smccc/kvm_guest.c @@ -2,8 +2,8 @@ #define pr_fmt(fmt) "smccc: KVM: " fmt -#include #include +#include #include #include @@ -13,8 +13,8 @@ static DECLARE_BITMAP(__kvm_arm_hyp_services, ARM_SMCCC_KVM_NUM_FUNCS) __ro_afte void __init kvm_init_hyp_services(void) { - int i; struct arm_smccc_res res; + u32 val[4]; if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_HVC) return; @@ -28,16 +28,13 @@ void __init kvm_init_hyp_services(void) memset(&res, 0, sizeof(res)); arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID, &res); - for (i = 0; i < 32; ++i) { - if (res.a0 & (i)) - set_bit(i + (32 * 0), __kvm_arm_hyp_services); - if (res.a1 & (i)) - set_bit(i + (32 * 1), __kvm_arm_hyp_services); - if (res.a2 & (i)) - set_bit(i + (32 * 2), __kvm_arm_hyp_services); - if (res.a3 & (i)) - set_bit(i + (32 * 3), __kvm_arm_hyp_services); - } + + val[0] = lower_32_bits(res.a0); + val[1] = lower_32_bits(res.a1); + val[2] = lower_32_bits(res.a2); + val[3] = lower_32_bits(res.a3); + + bitmap_from_arr32(__kvm_arm_hyp_services, val, ARM_SMCCC_KVM_NUM_FUNCS); pr_info("hypervisor services detected (0x%08lx 0x%08lx 0x%08lx 0x%08lx)\n", res.a3, res.a2, res.a1, res.a0); -- Jazz is not dead. It just smells funny...