From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 20792383C90; Fri, 27 Mar 2026 11:36:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774611387; cv=none; b=XJZHxIMzN6V/IRzqXH3R/cg6eg37MuELmBMMQXRXmC+DVD6xkYjKi66G/dWtTS7G+AqRdyztpMoeBZELCEKsQexDp6Md/Km5pEGqA0W9XjG5HaTVrZTd5Gqc94kFEgLVLJe76yrSUMbTpIUoI+Xf9DHHx14f6P5ceEssrJ0NCgI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774611387; c=relaxed/simple; bh=N9bhiVx5Vh1CUIB4IHblaqgBEI4KzyxLhqGgwc8mT8U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TRZGQGchy8P9pO+1jwHGO3hwzBKUbRYiPRUTgx97TtLmRKPhJFTypPKhz+IwfTCkqG6fN2p+hXskO/gueCb1vYfkFhM7j1tTqpvTDyi6TUl1S/ViCAheVnS+3P4Lq7DvO0+Vo1JyDDyO+++DTLntb61mQKiwKMOiMeCZ/O2mEso= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZXcZJB+f; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZXcZJB+f" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D42BBC19423; Fri, 27 Mar 2026 11:36:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774611386; bh=N9bhiVx5Vh1CUIB4IHblaqgBEI4KzyxLhqGgwc8mT8U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZXcZJB+fmHnNctN4JagniqSKrNn0NZ+FF4d2/PMUsVXHYe5ozVi1Vs6wDCbhkMWVl kbtsBMwriXE8+iqnod94kKQkkDBVidwwEVKZcZ4hI4MrVEg4e+awoETdz8J3zNhWZ4 jUCKaCTeno52ao89BJn2QEn75PidrxH8ZDQtZyO/KVhspUdROjDEry0V3FvSHUaM// DR6stROoc8egaC8wuX45Sxu8jE+suyLZlCYKjg/jxRWbnyr/LVNDORgcwGNy4vktIs MOOMECQw3PCmkSSSDiTQlcf3OcNMrRBR0GR08ZosciOpZgKGGTX2eYWtihYX+zpLG7 M+5v6BFhqS9Xg== Received: from sofa.misterjones.org ([185.219.108.64] helo=valley-girl.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1w65UG-00000006K4a-4Adm; Fri, 27 Mar 2026 11:36:25 +0000 From: Marc Zyngier To: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org Cc: Joey Gouly , Suzuki K Poulose , Oliver Upton , Zenghui Yu , Fuad Tabba , Will Deacon , Quentin Perret Subject: [PATCH v2 12/30] KVM: arm64: Hoist MTE validation check out of MMU lock path Date: Fri, 27 Mar 2026 11:36:00 +0000 Message-ID: <20260327113618.4051534-13-maz@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260327113618.4051534-1-maz@kernel.org> References: <20260327113618.4051534-1-maz@kernel.org> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, joey.gouly@arm.com, suzuki.poulose@arm.com, oupton@kernel.org, yuzenghui@huawei.com, tabba@google.com, will@kernel.org, qperret@google.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false From: Fuad Tabba Simplify the non-cacheable attributes assignment by using a ternary operator. Additionally, hoist the MTE validation check (mte_allowed) out of kvm_s2_fault_map() and into kvm_s2_fault_compute_prot(). This allows us to fail faster and avoid acquiring the KVM MMU lock unnecessarily when the VMM introduces a disallowed VMA for an MTE-enabled guest. Signed-off-by: Fuad Tabba Signed-off-by: Marc Zyngier --- arch/arm64/kvm/mmu.c | 28 ++++++++++++---------------- 1 file changed, 12 insertions(+), 16 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 0c71e3a9af8b0..ee2a548999b1b 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1870,18 +1870,21 @@ static int kvm_s2_fault_compute_prot(struct kvm_s2_fault *fault) if (fault->exec_fault) fault->prot |= KVM_PGTABLE_PROT_X; - if (fault->s2_force_noncacheable) { - if (fault->vm_flags & VM_ALLOW_ANY_UNCACHED) - fault->prot |= KVM_PGTABLE_PROT_NORMAL_NC; - else - fault->prot |= KVM_PGTABLE_PROT_DEVICE; - } else if (cpus_have_final_cap(ARM64_HAS_CACHE_DIC)) { + if (fault->s2_force_noncacheable) + fault->prot |= (fault->vm_flags & VM_ALLOW_ANY_UNCACHED) ? + KVM_PGTABLE_PROT_NORMAL_NC : KVM_PGTABLE_PROT_DEVICE; + else if (cpus_have_final_cap(ARM64_HAS_CACHE_DIC)) fault->prot |= KVM_PGTABLE_PROT_X; - } if (fault->nested) adjust_nested_exec_perms(kvm, fault->nested, &fault->prot); + if (!fault->fault_is_perm && !fault->s2_force_noncacheable && kvm_has_mte(kvm)) { + /* Check the VMM hasn't introduced a new disallowed VMA */ + if (!fault->mte_allowed) + return -EFAULT; + } + return 0; } @@ -1918,15 +1921,8 @@ static int kvm_s2_fault_map(struct kvm_s2_fault *fault, void *memcache) } } - if (!fault->fault_is_perm && !fault->s2_force_noncacheable && kvm_has_mte(kvm)) { - /* Check the VMM hasn't introduced a new disallowed VMA */ - if (fault->mte_allowed) { - sanitise_mte_tags(kvm, fault->pfn, fault->vma_pagesize); - } else { - ret = -EFAULT; - goto out_unlock; - } - } + if (!fault->fault_is_perm && !fault->s2_force_noncacheable && kvm_has_mte(kvm)) + sanitise_mte_tags(kvm, fault->pfn, fault->vma_pagesize); /* * Under the premise of getting a FSC_PERM fault, we just need to relax -- 2.47.3