From patchwork Tue Mar 19 15:42:52 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Anthony PERARD X-Patchwork-Id: 1058489 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=citrix.com Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 44Ny8X4yd4z9s9T for ; Wed, 20 Mar 2019 02:46:36 +1100 (AEDT) Received: from localhost ([127.0.0.1]:59164 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1h6Gwk-0005rY-AZ for incoming@patchwork.ozlabs.org; Tue, 19 Mar 2019 11:46:34 -0400 Received: from eggs.gnu.org ([209.51.188.92]:53564) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1h6Gvy-0005pR-8w for qemu-devel@nongnu.org; Tue, 19 Mar 2019 11:45:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1h6Gvv-0003f5-3O for qemu-devel@nongnu.org; Tue, 19 Mar 2019 11:45:44 -0400 Received: from smtp03.citrix.com ([162.221.156.55]:34254) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1h6Gvu-0003cH-3y for qemu-devel@nongnu.org; Tue, 19 Mar 2019 11:45:42 -0400 X-IronPort-AV: E=Sophos;i="5.58,498,1544486400"; d="scan'208";a="81019071" From: Anthony PERARD To: Date: Tue, 19 Mar 2019 15:42:52 +0000 Message-ID: <20190319154253.1494-2-anthony.perard@citrix.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190319154253.1494-1-anthony.perard@citrix.com> References: <20190319154253.1494-1-anthony.perard@citrix.com> MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 162.221.156.55 Subject: [Qemu-devel] [PULL 1/1] xen-mapcache: use MAP_FIXED flag so the mmap address hint is always honored X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: xen-devel@lists.xenproject.org, Peter Maydell Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" From: Roger Pau Monne Or if it's not possible to honor the hinted address an error is returned instead. This makes it easier to spot the actual failure, instead of failing later on when the caller of xen_remap_bucket realizes the mapping has not been created at the requested address. Also note that at least on FreeBSD using MAP_FIXED will cause mmap to try harder to honor the passed address. Signed-off-by: Roger Pau Monné Reviewed-by: Paul Durrant Acked-by: Anthony PERARD Reviewed-by: Igor Druzhinin Message-Id: <20190318173731.14494-1-roger.pau@citrix.com> Signed-off-by: Anthony PERARD --- hw/i386/xen/xen-mapcache.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/hw/i386/xen/xen-mapcache.c b/hw/i386/xen/xen-mapcache.c index 349f72d00c..254759f776 100644 --- a/hw/i386/xen/xen-mapcache.c +++ b/hw/i386/xen/xen-mapcache.c @@ -184,9 +184,14 @@ static void xen_remap_bucket(MapCacheEntry *entry, pfns[i] = (address_index << (MCACHE_BUCKET_SHIFT-XC_PAGE_SHIFT)) + i; } + /* + * If the caller has requested the mapping at a specific address use + * MAP_FIXED to make sure it's honored. + */ if (!dummy) { vaddr_base = xenforeignmemory_map2(xen_fmem, xen_domid, vaddr, - PROT_READ | PROT_WRITE, 0, + PROT_READ | PROT_WRITE, + vaddr ? MAP_FIXED : 0, nb_pfn, pfns, err); if (vaddr_base == NULL) { perror("xenforeignmemory_map2"); @@ -198,7 +203,8 @@ static void xen_remap_bucket(MapCacheEntry *entry, * mapping immediately due to certain circumstances (i.e. on resume now) */ vaddr_base = mmap(vaddr, size, PROT_READ | PROT_WRITE, - MAP_ANON | MAP_SHARED, -1, 0); + MAP_ANON | MAP_SHARED | (vaddr ? MAP_FIXED : 0), + -1, 0); if (vaddr_base == MAP_FAILED) { perror("mmap"); exit(-1);