From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60640) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dFjvW-0005Cm-N8 for qemu-devel@nongnu.org; Tue, 30 May 2017 12:23:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dFjvT-0004mg-I1 for qemu-devel@nongnu.org; Tue, 30 May 2017 12:23:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48154) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dFjvT-0004mP-C9 for qemu-devel@nongnu.org; Tue, 30 May 2017 12:23:19 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1B25EC059722 for ; Tue, 30 May 2017 16:23:18 +0000 (UTC) References: <1496030545-8719-1-git-send-email-peterx@redhat.com> From: Paolo Bonzini Message-ID: <624c0eb9-083f-d6e8-16b7-998082e1e470@redhat.com> Date: Tue, 30 May 2017 18:23:14 +0200 MIME-Version: 1.0 In-Reply-To: <1496030545-8719-1-git-send-email-peterx@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit 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: Peter Xu , qemu-devel@nongnu.org Cc: Maxime Coquelin 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? Thanks, Paolo > } > > - /* Convert to address mask */ > - plen -= 1; > - > return (IOMMUTLBEntry) { > .target_as = section.address_space, > .iova = addr & ~plen, >