From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53639) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dFx3G-0001JL-NO for qemu-devel@nongnu.org; Wed, 31 May 2017 02:24:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dFx3B-0001Wa-QE for qemu-devel@nongnu.org; Wed, 31 May 2017 02:24:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54984) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dFx3B-0001Vz-Ki for qemu-devel@nongnu.org; Wed, 31 May 2017 02:24:09 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id CCB178123D for ; Wed, 31 May 2017 06:24:06 +0000 (UTC) Date: Wed, 31 May 2017 14:23:57 +0800 From: Peter Xu Message-ID: <20170531062357.GD14845@pxdev.xzpeter.org> References: <1496030545-8719-1-git-send-email-peterx@redhat.com> <624c0eb9-083f-d6e8-16b7-998082e1e470@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <624c0eb9-083f-d6e8-16b7-998082e1e470@redhat.com> Subject: Re: [Qemu-devel] [PATCH v2] exec: fix address_space_get_iotlb_entry page mask List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: qemu-devel@nongnu.org, Maxime Coquelin On Tue, May 30, 2017 at 06:23:14PM +0200, Paolo Bonzini wrote: > > > On 29/05/2017 06:02, Peter Xu wrote: > > The IOTLB that it returned didn't guarantee that page_mask is indeed a > > so-called page mask. That won't affect current usage since now only > > vhost is using it (vhost API allows arbitary IOTLB range). However we > > have IOTLB scemantic and we should best follow it. This patch fixes this > > issue to make sure the page_mask is always a valid page mask. > > > > Fixes: a764040 ("exec: abstract address_space_do_translate()") > > Signed-off-by: Peter Xu > > --- > > Sorry please use this one. The codes is merely the same, just avoided > > moving the codes around unnecessarily. > > --- > > exec.c | 14 ++++++-------- > > 1 file changed, 6 insertions(+), 8 deletions(-) > > > > diff --git a/exec.c b/exec.c > > index ff16f04..3db247c 100644 > > --- a/exec.c > > +++ b/exec.c > > @@ -529,16 +529,14 @@ IOMMUTLBEntry address_space_get_iotlb_entry(AddressSpace *as, hwaddr addr, > > section.offset_within_region; > > > > if (plen == (hwaddr)-1) { > > - /* > > - * We use default page size here. Logically it only happens > > - * for identity mappings. > > - */ > > - plen = TARGET_PAGE_SIZE; > > + /* If not specified during translation, use default mask */ > > + plen = TARGET_PAGE_MASK; > > + } else { > > + /* Make it a valid page mask */ > > + assert(plen); > > + plen = (1ULL << (63 - clz64(plen))) - 1; > > Would pow2floor be better? Yes. :) Will respin. Thanks! -- Peter Xu