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 X-Spam-Level: X-Spam-Status: No, score=-4.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D96E7C433E0 for ; Tue, 26 May 2020 06:15:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B60DC20E65 for ; Tue, 26 May 2020 06:15:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590473713; bh=Ur2xk8PlFAdp1SqkrrLV/Z2pOfVx2LArPwI0PTzFmSM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=xB9YmVoNcUB4W+yaAhNHs3yArlWhniaclFIxHJSHQGEJ7iI6dTwsNJFfmZZNdEeIE pcAtPlZ7vhIJdurK0ino7PU+Gvx0uTdUReCTt2LnSXeb7SMe9U6+VrQwbaADpAtfk2 xvnT2cJ5ANCHoo1rNfI2PrVN6jLOciPT2sfjmMBA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726900AbgEZGPK (ORCPT ); Tue, 26 May 2020 02:15:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:60382 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725271AbgEZGPK (ORCPT ); Tue, 26 May 2020 02:15:10 -0400 Received: from kernel.org (unknown [87.70.212.59]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 486852087D; Tue, 26 May 2020 06:15:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590473709; bh=Ur2xk8PlFAdp1SqkrrLV/Z2pOfVx2LArPwI0PTzFmSM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=x53IR6Jdx8v+FrtVJ0pEbhAPnAPzTg32Pwto6iDx+Ywedcvs89VietzhFi20djMuN ej5tZ8gwm15PMi3B93btNoJ557MZ0g0SkVLmdgW4rddWFSquUFwjDQixRHA4VIeQJm UePksupJX9ie1uyLj4nEt1GIV8f1CBnRdXwGjwUw= Date: Tue, 26 May 2020 09:14:59 +0300 From: Mike Rapoport To: "Kirill A. Shutemov" Cc: Dave Hansen , Andy Lutomirski , Peter Zijlstra , Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , David Rientjes , Andrea Arcangeli , Kees Cook , Will Drewry , "Edgecombe, Rick P" , "Kleen, Andi" , x86@kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: Re: [RFC 06/16] KVM: Use GUP instead of copy_from/to_user() to access guest memory Message-ID: <20200526061459.GC13247@kernel.org> References: <20200522125214.31348-1-kirill.shutemov@linux.intel.com> <20200522125214.31348-7-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200522125214.31348-7-kirill.shutemov@linux.intel.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Fri, May 22, 2020 at 03:52:04PM +0300, Kirill A. Shutemov wrote: > New helpers copy_from_guest()/copy_to_guest() to be used if KVM memory > protection feature is enabled. > > Signed-off-by: Kirill A. Shutemov > --- > include/linux/kvm_host.h | 4 +++ > virt/kvm/kvm_main.c | 78 ++++++++++++++++++++++++++++++++++------ > 2 files changed, 72 insertions(+), 10 deletions(-) > > static int __kvm_read_guest_page(struct kvm_memory_slot *slot, gfn_t gfn, > - void *data, int offset, int len) > + void *data, int offset, int len, > + bool protected) > { > int r; > unsigned long addr; > @@ -2257,7 +2297,10 @@ 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; > - r = __copy_from_user(data, (void __user *)addr + offset, len); > + if (protected) > + r = copy_from_guest(data, addr + offset, len); > + else > + r = __copy_from_user(data, (void __user *)addr + offset, len); Maybe always use copy_{from,to}_guest() and move the 'if (protected)' there? If kvm is added to memory slot, it cab be the passed to copy_{to,from}_guest. > if (r) > return -EFAULT; > return 0; > @@ -2268,7 +2311,8 @@ 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(slot, gfn, data, offset, len, > + kvm->mem_protected); > } > EXPORT_SYMBOL_GPL(kvm_read_guest_page); > > @@ -2277,7 +2321,8 @@ 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(slot, gfn, data, offset, len, > + vcpu->kvm->mem_protected); > } > EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest_page); > -- Sincerely yours, Mike.