From nobody Wed Dec 17 12:06:35 2025 Received: from mail-yb1-f201.google.com (mail-yb1-f201.google.com [209.85.219.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0099516132B for ; Wed, 10 Jul 2024 23:42:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720654972; cv=none; b=b12NfgIRYTLxcAUImABfsp8OcXjOlmxHE1VuXlJmbjJNMLDNRrD6PLb1nPMtpMtflKavdVywpPRPRu62JSGzBgNuGH6OMRs15gdKOC8YQmbclnXtT1N62V6EYplhGF51zWkvA3G+2pnwOq1KvYNIl8arM90CUBJYICxno7aGsPo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720654972; c=relaxed/simple; bh=51xqz35xJjNqxl6o9J1L1+yTufTjMwvN6j0qSUdwPuQ=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Hh31mmcnjy7mGMJC75v20zH/SGLy4iPr7jHk2SMLbot1fFzq1LYK9oRI8c9gn2D1ClElOOfaYSMekJa0QQUCYtwVz/kST9/9O0J3XuMKwZUTZVTqpZYpz9D5J8o3/hRD0njAZBzIKf9oHBMBei6zrRSGsbndgJ1SRw40c746mZw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--jthoughton.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=DWy7bWTF; arc=none smtp.client-ip=209.85.219.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--jthoughton.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="DWy7bWTF" Received: by mail-yb1-f201.google.com with SMTP id 3f1490d57ef6-e037c3d20a6so518299276.0 for ; Wed, 10 Jul 2024 16:42:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1720654968; x=1721259768; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=m+X5KVuFwrRiCUCCxSkgB4VRafKsM+RRSJ9rZMEadTc=; b=DWy7bWTFhe/KIs13Ct3SsUbD+oF93GBAGRkLqujDeMAfUYNC12irf/BXHA7+3oTOx4 4Fpwge7jjhMAE+omuvcFPSamQ/Q+FundE26AFNHWZ+TyrVhXwEZgu5nASqzHrPmZQqBp jwNYETChRg+l0zLY/dduL+CRaYYdWCfHnTVFR/hr7speNuvW2qFeNXHgpjzatRI4Hljf B980UHG+z1+ukIYI+53h60THD/CUgre1E4gv0S5dmAI8kNFLoczV0HLOJIUu20HV0jhV nThjBZO8gAQL9cgx6a7vznQJQpk1IBIkPWTvDYbETqPveDo7579rtaQRFKFBoOvpoBuG fhig== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1720654968; x=1721259768; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=m+X5KVuFwrRiCUCCxSkgB4VRafKsM+RRSJ9rZMEadTc=; b=efbefmMN8eqnsCNAwaJwX/+/10WKIX5ZQIEeaDpuDtct1Xnqk66TDuKxRA1RNlvTjT ZZMP1X50nYXjzWYmYRPdXcWTrC+iPDjlZcyOSXTyaTTa66YhLdkmf498RvOHLsdCCf9D 9it0apSqFpq6TDcEE0U+gkOKhxOyBtuLyoE2bDhtIROltrs8jx9vaTxRIs6KybtZnwOI up8+Ky/VEc61xF6Tk6KkM26NU5txKF+tLkF8fM/v5544d++fiIYE9ryS0kG+pr7RMqTv Y9EP880fABAi+FW2ineR++/uPJzDT9hhUCkoYVw3r/MHjKOStIguqzWVWddatu0qWjwY pYbg== X-Forwarded-Encrypted: i=1; AJvYcCVRvUzUHQAdjqVXBVAIxT3JcF44/Jb+UD16Tto8+/drowF73jyBzOait0i7dtZEanWEIVtmCIOsSGS7xI8J5CSI4xBQ/y5P660qsbMV X-Gm-Message-State: AOJu0YweFs+Xl6X9LLT7O1hKCfcLd5Nxfwnl10ODCqo5IyMc/u/5166Y yMx55YsUQwVnh6biigUY/CV8SBWq5NujkaEWC1H1ECSkuxz+UBFZcKOnZdDCW93Cv5ezhN8Bom8 Rf7weXYQ73NcKmOQgbQ== X-Google-Smtp-Source: AGHT+IEiMSeqlL0E6QDriJWFXsS3O5CZdgADUq/m5UJK+f9Pzpz6qFNvBqMVhziD7REowA6fLBLwvMzZP6ooxfuZ X-Received: from jthoughton.c.googlers.com ([fda3:e722:ac3:cc00:14:4d90:c0a8:2a4f]) (user=jthoughton job=sendgmr) by 2002:a05:6902:2089:b0:e03:2bfe:40c9 with SMTP id 3f1490d57ef6-e041b032f48mr13750276.3.1720654967914; Wed, 10 Jul 2024 16:42:47 -0700 (PDT) Date: Wed, 10 Jul 2024 23:42:14 +0000 In-Reply-To: <20240710234222.2333120-1-jthoughton@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240710234222.2333120-1-jthoughton@google.com> X-Mailer: git-send-email 2.45.2.993.g49e7a77208-goog Message-ID: <20240710234222.2333120-11-jthoughton@google.com> Subject: [RFC PATCH 10/18] KVM: arm64: Add KVM Userfault support From: James Houghton To: Paolo Bonzini Cc: Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Zenghui Yu , Sean Christopherson , Shuah Khan , Peter Xu , Axel Rasmussen , David Matlack , James Houghton , kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Support comes in three parts: 1. When KVM Userfault is enabled, only install PAGE_SIZE PTEs. This prevents us from being able to map a userfault-enabled pfn with a huge PTE in response to a fault on a non-userfault pfn. 2. When we get KVM_PFN_ERR_USERFAULT from __gfn_to_pfn_memslot, return a memory fault to userspace. 3. When KVM Userfault is enabled for a particular kvm_gfn_range, unmap it, so that we can get faults on it. Signed-off-by: James Houghton --- arch/arm64/kvm/Kconfig | 1 + arch/arm64/kvm/mmu.c | 36 ++++++++++++++++++++++++++++++++++-- 2 files changed, 35 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index 58f09370d17e..358153d91d58 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -37,6 +37,7 @@ menuconfig KVM select HAVE_KVM_VCPU_RUN_PID_CHANGE select SCHED_INFO select GUEST_PERF_EVENTS if PERF_EVENTS + select KVM_USERFAULT help Support hosting virtualized guest machines. =20 diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 8bcab0cc3fe9..ac283e606516 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1434,7 +1434,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys= _addr_t fault_ipa, * logging_active is guaranteed to never be true for VM_PFNMAP * memslots. */ - if (logging_active) { + if (logging_active || kvm->userfault) { force_pte =3D true; vma_shift =3D PAGE_SHIFT; } else { @@ -1494,8 +1494,15 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phy= s_addr_t fault_ipa, kvm_send_hwpoison_signal(hva, vma_shift); return 0; } - if (is_error_noslot_pfn(pfn)) + if (is_error_noslot_pfn(pfn)) { + if (pfn =3D=3D KVM_PFN_ERR_USERFAULT) + kvm_prepare_memory_fault_exit(vcpu, gfn << PAGE_SHIFT, + PAGE_SIZE, write_fault, + /*exec=3D*/false, + /*private=3D*/false, + /*userfault=3D*/true); return -EFAULT; + } =20 if (kvm_is_device_pfn(pfn)) { /* @@ -2105,3 +2112,28 @@ void kvm_toggle_cache(struct kvm_vcpu *vcpu, bool wa= s_enabled) =20 trace_kvm_toggle_cache(*vcpu_pc(vcpu), was_enabled, now_enabled); } + +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES +bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm, + struct kvm_gfn_range *range) +{ + unsigned long attrs =3D range->arg.attributes; + + /* + * We only need to unmap if we're enabling userfault. Disabling it + * does not need an unmap. An unmap to get huge mappings will come + * later. + */ + if (attrs & KVM_MEMORY_ATTRIBUTE_USERFAULT) + kvm_unmap_gfn_range(kvm, range); + + return false; +} + +bool kvm_arch_post_set_memory_attributes(struct kvm *kvm, + struct kvm_gfn_range *range) +{ + /* Nothing to do! */ + return false; +} +#endif --=20 2.45.2.993.g49e7a77208-goog