From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 48BF150E5A1 for ; Fri, 18 Sep 2026 13:50:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789739457; cv=none; b=iKIMA2W42Qa5lYJy6XeB/652UtNHK5MNB6wxrGOGCnPfORKgp10BjTrmdqdJJY1TMRU4ZtiIj0awam/is17fuj3vlDXUYY1spyFCmqgPRkwMqvV+bNgaG6fizJhizL4BCRvdZZB5R/TH3L7/FAhFc387F6KnGSFvD96gik1zmbo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789739457; c=relaxed/simple; bh=PDbhJnSJId/nHkHj+x63VXubJEYI1c0DioQfK3uXkPQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=FGsEpELp+aIHcpO1lH6CewJHmd+4uIUvuu244TRIDciYo7ONFYqlHwwtC49WJeTEJNWUuceuFuf6q4r0iyX72hnPYFz6K5x5M/ttm2dMwchQqozm5mWvfxbxp8tyGYGlBhhFDWKPNAMQnMEfCjB3mAkmV4YObcXHNGft8g3cv9c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=aH3n2wL6; arc=none smtp.client-ip=170.10.133.124 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) header.d=redhat.com header.i=@redhat.com header.b="aH3n2wL6" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1789739450; 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=+VFgdxHE6+HrrZypJ8OgwWId3lIAfHbeaGvwUSKqkUU=; b=aH3n2wL6P1zOaHPl2o01du7wgLH5ZnhUigNlsC+xbLPxr2ZaGN3T82FDK+6UgM1cNG9+qV YRY9wXFOuT7qZhUZLvy5T3NX6ez7aabUiucUtGqcwVsk04ON4yfPnkp8bUeEMpTATVUheh mdta5RY8wKzrZ9TnJr9HxDOPxz/e9Zs= 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-662-DbsSG9W3M7e9QFi-nE7ttw-1; Fri, 18 Sep 2026 09:50:47 -0400 X-MC-Unique: DbsSG9W3M7e9QFi-nE7ttw-1 X-Mimecast-MFC-AGG-ID: DbsSG9W3M7e9QFi-nE7ttw_1789739446 Received: from mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.95]) (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 6686A195E937; Fri, 18 Sep 2026 13:50:46 +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-10.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id BDF09433; Fri, 18 Sep 2026 13:50:45 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: nsaenz@amazon.com, vkuznets@redhat.com, snambakam@linux.microsoft.com Subject: [PATCH 16/31] KVM: Take memory protections into account for memory read/write/fetch Date: Fri, 18 Sep 2026 09:50:15 -0400 Message-ID: <20260918135030.171564-17-pbonzini@redhat.com> In-Reply-To: <20260918135030.171564-1-pbonzini@redhat.com> References: <20260918135030.171564-1-pbonzini@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.6 on 10.30.177.95 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 --- 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 9fdec95ccce2..acf09059a1cd 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3253,11 +3253,13 @@ 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; @@ -3265,6 +3267,11 @@ 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_memory_attributes(kvm, gfn); + if (attrs & attr) + return -EFAULT; + r = __copy_from_user(data, (void __user *)addr + offset, len); if (r) return -EFAULT; @@ -3276,7 +3283,8 @@ 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); @@ -3285,7 +3293,8 @@ 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); @@ -3294,7 +3303,8 @@ 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); @@ -3338,8 +3348,9 @@ 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; @@ -3347,6 +3358,9 @@ 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; @@ -3365,7 +3379,7 @@ 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); @@ -3383,6 +3397,10 @@ 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