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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 62C86105F7AE for ; Fri, 13 Mar 2026 14:47:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=6sfx0BeCK4o2PZRm2XbT6L66llJyNvYMEO46iAjdFYg=; b=RkdAJ9J9609EpsfT7W3aFEmawk PtfcTCObSnXf+wSCoBb0LOCmolj+weViGOeBtwsUZk+9O77qM5hd0Nu/pE7s0tlQA5CpIO9oik5BP fNQNn2O82GYZBNUVlzFpb/iChDinmm+ZpY65gzLl3dplb0zYW5nKJwz97lVi3dRc6H2AqK/b+vTIq EzPpPiYvY415TaBbMbkKGfL+TIGfB2O/ML0a6mpcbvK2CkDkOuwPuehoulgYDOpf1OWK4Eu1OB77o AkQ/lW29O5aNBSrZdu9auEBtGI7pISloW8ALAHWHRjEm+KGO5u8Me1BbCJXX1V0YkAO1/7dTdpgaQ 1zqx+62g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w13nX-00000000QyL-26m1; Fri, 13 Mar 2026 14:47:31 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w13nU-00000000QvA-0FaP for linux-arm-kernel@lists.infradead.org; Fri, 13 Mar 2026 14:47:29 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B9C141E7D; Fri, 13 Mar 2026 07:47:20 -0700 (PDT) Received: from e134344.cambridge.arm.com (e134344.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id EAE403F7BD; Fri, 13 Mar 2026 07:47:22 -0700 (PDT) From: Ben Horgan To: ben.horgan@arm.com Cc: amitsinght@marvell.com, baisheng.gao@unisoc.com, baolin.wang@linux.alibaba.com, carl@os.amperecomputing.com, dave.martin@arm.com, david@kernel.org, dfustini@baylibre.com, fenghuay@nvidia.com, gshan@redhat.com, james.morse@arm.com, jonathan.cameron@huawei.com, kobak@nvidia.com, lcherian@marvell.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, peternewman@google.com, punit.agrawal@oss.qualcomm.com, quic_jiles@quicinc.com, reinette.chatre@intel.com, rohit.mathew@arm.com, scott@os.amperecomputing.com, sdonthineni@nvidia.com, tan.shaopeng@fujitsu.com, xhao@linux.alibaba.com, catalin.marinas@arm.com, will@kernel.org, corbet@lwn.net, maz@kernel.org, oupton@kernel.org, joey.gouly@arm.com, suzuki.poulose@arm.com, kvmarm@lists.linux.dev, zengheng4@huawei.com, linux-doc@vger.kernel.org, Shaopeng Tan Subject: [PATCH v6 13/40] KVM: arm64: Force guest EL1 to use user-space's partid configuration Date: Fri, 13 Mar 2026 14:45:50 +0000 Message-ID: <20260313144617.3420416-14-ben.horgan@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260313144617.3420416-1-ben.horgan@arm.com> References: <20260313144617.3420416-1-ben.horgan@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260313_074728_223665_1519E52D X-CRM114-Status: GOOD ( 10.43 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: James Morse While we trap the guest's attempts to read/write the MPAM control registers, the hardware continues to use them. Guest-EL0 uses KVM's user-space's configuration, as the value is left in the register, and guest-EL1 uses either the host kernel's configuration, or in the case of VHE, the UNKNOWN reset value of MPAM1_EL1. We want to force the guest-EL1 to use KVM's user-space's MPAM configuration. On nVHE rely on MPAM0_EL1 and MPAM1_EL1 always being programmed the same and on VHE copy MPAM0_EL1 into the guest's MPAM1_EL1. There is no need to restore as this is out of context once TGE is set. Tested-by: Gavin Shan Tested-by: Shaopeng Tan Tested-by: Peter Newman Tested-by: Zeng Heng Tested-by: Punit Agrawal Reviewed-by: Zeng Heng Reviewed-by: Shaopeng Tan Reviewed-by: Jonathan Cameron Reviewed-by: Gavin Shan Acked-by: Marc Zyngier Signed-off-by: James Morse Signed-off-by: Ben Horgan --- Changes since rfc: Drop the unneeded __mpam_guest_load() in nvhre and the MPAM1_EL1 save restore Defer EL2 handling until next patch Changes since v2: Use mask (Oliver) Changes since v4: Explicitly set the mpam enable bit --- arch/arm64/kvm/hyp/vhe/sysreg-sr.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/arch/arm64/kvm/hyp/vhe/sysreg-sr.c b/arch/arm64/kvm/hyp/vhe/sysreg-sr.c index b254d442e54e..be685b63e8cf 100644 --- a/arch/arm64/kvm/hyp/vhe/sysreg-sr.c +++ b/arch/arm64/kvm/hyp/vhe/sysreg-sr.c @@ -183,6 +183,21 @@ void sysreg_restore_guest_state_vhe(struct kvm_cpu_context *ctxt) } NOKPROBE_SYMBOL(sysreg_restore_guest_state_vhe); +/* + * The _EL0 value was written by the host's context switch and belongs to the + * VMM. Copy this into the guest's _EL1 register. + */ +static inline void __mpam_guest_load(void) +{ + u64 mask = MPAM0_EL1_PARTID_D | MPAM0_EL1_PARTID_I | MPAM0_EL1_PMG_D | MPAM0_EL1_PMG_I; + + if (system_supports_mpam()) { + u64 val = (read_sysreg_s(SYS_MPAM0_EL1) & mask) | MPAM1_EL1_MPAMEN; + + write_sysreg_el1(val, SYS_MPAM1); + } +} + /** * __vcpu_load_switch_sysregs - Load guest system registers to the physical CPU * @@ -222,6 +237,7 @@ void __vcpu_load_switch_sysregs(struct kvm_vcpu *vcpu) */ __sysreg32_restore_state(vcpu); __sysreg_restore_user_state(guest_ctxt); + __mpam_guest_load(); if (unlikely(is_hyp_ctxt(vcpu))) { __sysreg_restore_vel2_state(vcpu); -- 2.43.0