From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=170.10.133.124 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793641520; b=jfCsrn27I1+iw4eXp6Lfscid0lOEvMNTZcX5w0qTAfpKGMyurAZTZJXYO0lDgtvEUDGR y+zCTNo+JcYgyUkhlQLZhF1qKeBoVeGN5wGDAz5JmwLYm4co0A3on/XC9UOaYOhT/qkbZ ZpQAk/kDtKZv8JCj5pBNyc1mDrPlYA1Ps8R1E2XvJbMQG/fbi+MbykfA/wnewnPWeIMoq Mr78w7S/kXRCAh+s3oLqtvdC7zS//1P5Af5mVoXiSiKYvsT3KWp2jcMnVVJ+pBxKYt7Ln YNV+1EX/liEv0acWYSg0Q7avM+/z/gWC64ruUg5qfY9HxnPQk85d7/qtEmvcmWnLp6g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793641520; h=DMARC-Filter:DKIM-Signature:Received:X-MC-Unique: X-Mimecast-MFC-AGG-ID:Received:Received:From:To:Cc:Subject:Date: Message-ID:In-Reply-To:References:MIME-Version:Content-Type: Content-Transfer-Encoding:X-Scanned-By; bh=yaKAU6Ow7XUYCqR9G0iHJRFxDv4tOlXe6ZZRKBhpn4A=; b=o5tqONOPOJ8iHnPjXVBFCh6V26rfPB/e+4dRWrfVWZ63f1OKaUWuEXmqFFmZ3Ed3eSM/ mjRTBtGT5j7g+/S0mOht9ddNOMBRIWNcnrkOPloTTFxz38XO1QxRRt+X9lIdcUKxfw5RC QaTTsewcEtrOT9MdXyBy84YkAXmgARg9KtNgtr/AtopaanhngjM+W9GXoNjl8L5JtSKuY bQFXJIrveaO4rYoVya4iIr40u/upprAC6eMUOurzVWWsD4XZiwRosrk7Ku1faYKhq/a2V eOTf5Lw0P0ykqI2gTMWyNwiZTYxfcUxgDdRDJ+CqihJKKdxwuChy78/oYsW2LAJfrNw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=QCNuDBNo; arc=none smtp.remote-ip=170.10.133.124 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0FB83606E003 for ; Mon, 2 Nov 2026 17:45:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 0FB83606E003 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=QCNuDBNo DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1793641518; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=yaKAU6Ow7XUYCqR9G0iHJRFxDv4tOlXe6ZZRKBhpn4A=; b=QCNuDBNoD2i8HhPjANEi7klm55rAiV/PgjLB8u1/6BHliHfYdBqV/BADE53dRQk+SyPGpO Wwt4fHYtk/IY5JrS0yXB/x+W7kucuHDnG8+WaRvU3K7Px/yStttCNg9C7WkRIs8/eai6rE F0N2qo9ZcaYs/aw0i9owy41zFXfn/oQ= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-500-1HrbbgwANhGSxTtZ-qfKRg-1; Mon, 02 Nov 2026 12:45:16 -0500 X-MC-Unique: 1HrbbgwANhGSxTtZ-qfKRg-1 X-Mimecast-MFC-AGG-ID: 1HrbbgwANhGSxTtZ-qfKRg_1793641515 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id AA5871956064; Mon, 2 Nov 2026 17:45:15 +0000 (UTC) Received: from virtlab1023.virt.eng.rdu2.dc.redhat.com (virtlab1023.virt.eng.rdu2.dc.redhat.com [10.18.48.26]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 36FC71956087; Mon, 2 Nov 2026 17:45:15 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Nicolas Saenz Julienne Subject: [PATCH 20/45] KVM: Take memory protections into account for memory read/write/fetch Date: Mon, 2 Nov 2026 12:44:47 -0500 Message-ID: <20261102174512.8903-4-pbonzini@redhat.com> In-Reply-To: <20261102174130.8779-1-pbonzini@redhat.com> References: <20261102174130.8779-1-pbonzini@redhat.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 From: Nicolas Saenz Julienne Take into account memory attributes when accessing guest memory through the kvm_{read,write,fetch}*() family of functions. All of these pass a struct kvm_memory_slot pointer to the actual workhorse functions, in order to share code between the VM-wide and vCPU-specific version of the functions (the latter of which handles the multi-address-space case). For this reason they need specific changes and do not work even though the gfn_to_hva() path has been taught already about memory protection attributes. Signed-off-by: Nicolas Saenz Julienne Signed-off-by: Paolo Bonzini Link: https://patch.msgid.link/20260918135030.171564-17-pbonzini@redhat.com Signed-off-by: Paolo Bonzini --- virt/kvm/kvm_main.c | 34 ++++++++++++++++++++++++++-------- 1 file changed, 26 insertions(+), 8 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 41818ed5eb3a..de54f52f2158 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3362,11 +3362,13 @@ static int next_segment(unsigned long len, int offset) } /* Copy @len bytes from guest memory at '(@gfn * PAGE_SIZE) + @offset' to @data */ -static int __kvm_read_guest_page(struct kvm_memory_slot *slot, gfn_t gfn, - void *data, int offset, int len) +static int __kvm_read_guest_page(struct kvm *kvm, struct kvm_memory_slot *slot, + gfn_t gfn, void *data, int offset, int len, + unsigned long attr) { int r; unsigned long addr; + unsigned long attrs; if (WARN_ON_ONCE(offset + len > PAGE_SIZE)) return -EFAULT; @@ -3374,6 +3376,11 @@ static int __kvm_read_guest_page(struct kvm_memory_slot *slot, gfn_t gfn, addr = gfn_to_hva_memslot_prot(slot, gfn, NULL); if (kvm_is_error_hva(addr)) return -EFAULT; + + attrs = kvm_get_vm_memory_attributes(kvm, gfn); + if (attrs & attr) + return -EFAULT; + r = __copy_from_user(data, (void __user *)addr + offset, len); if (r) return -EFAULT; @@ -3385,7 +3392,8 @@ int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset, { struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn); - return __kvm_read_guest_page(slot, gfn, data, offset, len); + return __kvm_read_guest_page(kvm, slot, gfn, data, offset, len, + KVM_MEMORY_ATTRIBUTE_NR); } EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_read_guest_page); @@ -3394,7 +3402,8 @@ int kvm_vcpu_read_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn, void *data, { struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); - return __kvm_read_guest_page(slot, gfn, data, offset, len); + return __kvm_read_guest_page(vcpu->kvm, slot, gfn, data, offset, len, + KVM_MEMORY_ATTRIBUTE_NR); } EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_read_guest_page); @@ -3403,7 +3412,8 @@ int kvm_vcpu_fetch_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn, void *data, { struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); - return __kvm_read_guest_page(slot, gfn, data, offset, len); + return __kvm_read_guest_page(vcpu->kvm, slot, gfn, data, offset, len, + KVM_MEMORY_ATTRIBUTE_NX); } EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_fetch_guest_page); @@ -3447,8 +3457,9 @@ int kvm_vcpu_read_guest(struct kvm_vcpu *vcpu, gpa_t gpa, void *data, unsigned l } EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_read_guest); -static int __kvm_read_guest_atomic(struct kvm_memory_slot *slot, gfn_t gfn, - void *data, int offset, unsigned long len) +static int __kvm_read_guest_atomic(struct kvm *kvm, + struct kvm_memory_slot *slot, gfn_t gfn, + void *data, int offset, unsigned long len) { int r; unsigned long addr; @@ -3456,6 +3467,9 @@ static int __kvm_read_guest_atomic(struct kvm_memory_slot *slot, gfn_t gfn, if (WARN_ON_ONCE(offset + len > PAGE_SIZE)) return -EFAULT; + if (!kvm_mem_attributes_may_read_gfn(kvm, gfn)) + return -EFAULT; + addr = gfn_to_hva_memslot_prot(slot, gfn, NULL); if (kvm_is_error_hva(addr)) return -EFAULT; @@ -3474,7 +3488,7 @@ int kvm_vcpu_read_guest_atomic(struct kvm_vcpu *vcpu, gpa_t gpa, struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); int offset = offset_in_page(gpa); - return __kvm_read_guest_atomic(slot, gfn, data, offset, len); + return __kvm_read_guest_atomic(vcpu->kvm, slot, gfn, data, offset, len); } EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_read_guest_atomic); @@ -3492,6 +3506,10 @@ static int __kvm_write_guest_page(struct kvm *kvm, addr = gfn_to_hva_memslot(memslot, gfn); if (kvm_is_error_hva(addr)) return -EFAULT; + + if (!kvm_mem_attributes_may_write_gfn(kvm, gfn)) + return -EFAULT; + r = __copy_to_user((void __user *)addr + offset, data, len); if (r) return -EFAULT; -- 2.52.0