From patchwork Tue Jul 28 11:37:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Andrew Cooper X-Patchwork-Id: 11688979 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 660D113B1 for ; Tue, 28 Jul 2020 11:39:36 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 41D07206D4 for ; Tue, 28 Jul 2020 11:39:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=citrix.com header.i=@citrix.com header.b="fdH3oDwt" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 41D07206D4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=citrix.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k0NvL-0006C7-97; Tue, 28 Jul 2020 11:37:35 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k0NvJ-0006Bw-Tb for xen-devel@lists.xenproject.org; Tue, 28 Jul 2020 11:37:33 +0000 X-Inumbo-ID: b9750142-d0c6-11ea-a8af-12813bfff9fa Received: from esa5.hc3370-68.iphmx.com (unknown [216.71.155.168]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id b9750142-d0c6-11ea-a8af-12813bfff9fa; Tue, 28 Jul 2020 11:37:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1595936252; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=C30vCiBJRWVkXa2f7MgjSiHtu+zIa4xf5Yikt9EeBnM=; b=fdH3oDwtkYReN3a/EGRfwUz4TF2umd7FiSBCUdJo6YacrK9ZerkYKUei kikt1cYEfGYvtXdJyn0VsACQiib9wEJx5zungJcYBMUczjRQsWhhCg0D1 +UxTjigSksyn7cOxJTeKXgwJUu3GcofzSxqlCrNZTcD7fH8xaTMmB5NdH 8=; Authentication-Results: esa5.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none IronPort-SDR: v8/lpfGxqn1loOuLjuecXkShCkCaTzInJqJvVSwD90xze7nR9dWxBGetJ8AkmkPDm6ggBCixtj fWgVUCLAw5wVADZIE/CwCCxOHO6HooXWpZyta1JLuWM5MuVJYdMxy9lBWTZvEC+zgLh1S/tlm6 aIzCb7YW6EpP8kpY/IcUlqBqP08k+uLsOlUvjdhrILKPD1gZqLHopcC8LU6l8bC0ewQkHqdlCo RHpjcua+Ef5zJdHsxucOLdUb96w23iXIsKBKaYbzokWui+CgrRwBsaZcyqU1iEZz4utw3fCO4Y plY= X-SBRS: 2.7 X-MesageID: 23524684 X-Ironport-Server: esa5.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.75,406,1589256000"; d="scan'208";a="23524684" From: Andrew Cooper To: Xen-devel Subject: [PATCH 2/5] xen/gnttab: Rework resource acquisition Date: Tue, 28 Jul 2020 12:37:08 +0100 Message-ID: <20200728113712.22966-3-andrew.cooper3@citrix.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20200728113712.22966-1-andrew.cooper3@citrix.com> References: <20200728113712.22966-1-andrew.cooper3@citrix.com> MIME-Version: 1.0 X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Hubert Jasudowicz , Stefano Stabellini , Julien Grall , Wei Liu , Konrad Rzeszutek Wilk , George Dunlap , Andrew Cooper , Paul Durrant , Jan Beulich , =?utf-8?q?Micha=C5=82_Leszczy=C5=84ski?= , Ian Jackson Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" The existing logic doesn't function in the general case for mapping a guests grant table, due to arbitrary 32 frame limit, and the default grant table limit being 64. In order to start addressing this, rework the existing grant table logic by implementing a single gnttab_acquire_resource(). This is far more efficient than the previous acquire_grant_table() in memory.c because it doesn't take the grant table write lock, and attempt to grow the table, for every single frame. The new gnttab_acquire_resource() function subsumes the previous two gnttab_get_{shared,status}_frame() helpers. No functional change. Signed-off-by: Andrew Cooper --- CC: George Dunlap CC: Ian Jackson CC: Jan Beulich CC: Konrad Rzeszutek Wilk CC: Stefano Stabellini CC: Wei Liu CC: Julien Grall CC: Paul Durrant CC: Michał Leszczyński CC: Hubert Jasudowicz --- xen/common/grant_table.c | 93 ++++++++++++++++++++++++++++++------------- xen/common/memory.c | 42 +------------------ xen/include/xen/grant_table.h | 19 ++++----- 3 files changed, 75 insertions(+), 79 deletions(-) diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c index 9f0cae52c0..122d1e7596 100644 --- a/xen/common/grant_table.c +++ b/xen/common/grant_table.c @@ -4013,6 +4013,72 @@ static int gnttab_get_shared_frame_mfn(struct domain *d, return 0; } +int gnttab_acquire_resource( + struct domain *d, unsigned int id, unsigned long frame, + unsigned int nr_frames, xen_pfn_t mfn_list[]) +{ + struct grant_table *gt = d->grant_table; + unsigned int i = nr_frames, tot_frames; + void **vaddrs; + int rc = 0; + + /* Input sanity. */ + if ( !nr_frames ) + return -EINVAL; + + /* Overflow checks */ + if ( frame + nr_frames < frame ) + return -EINVAL; + + tot_frames = frame + nr_frames; + if ( tot_frames != frame + nr_frames ) + return -EINVAL; + + /* Grow table if necessary. */ + grant_write_lock(gt); + switch ( id ) + { + mfn_t tmp; + + case XENMEM_resource_grant_table_id_shared: + rc = gnttab_get_shared_frame_mfn(d, tot_frames - 1, &tmp); + break; + + case XENMEM_resource_grant_table_id_status: + if ( gt->gt_version != 2 ) + { + default: + rc = -EINVAL; + break; + } + rc = gnttab_get_status_frame_mfn(d, tot_frames - 1, &tmp); + break; + } + + /* Any errors from growing the table? */ + if ( rc ) + goto out; + + switch ( id ) + { + case XENMEM_resource_grant_table_id_shared: + vaddrs = gt->shared_raw; + break; + + case XENMEM_resource_grant_table_id_status: + vaddrs = (void **)gt->status; + break; + } + + for ( i = 0; i < nr_frames; ++i ) + mfn_list[i] = virt_to_mfn(vaddrs[frame + i]); + + out: + grant_write_unlock(gt); + + return rc; +} + int gnttab_map_frame(struct domain *d, unsigned long idx, gfn_t gfn, mfn_t *mfn) { int rc = 0; @@ -4047,33 +4113,6 @@ int gnttab_map_frame(struct domain *d, unsigned long idx, gfn_t gfn, mfn_t *mfn) return rc; } -int gnttab_get_shared_frame(struct domain *d, unsigned long idx, - mfn_t *mfn) -{ - struct grant_table *gt = d->grant_table; - int rc; - - grant_write_lock(gt); - rc = gnttab_get_shared_frame_mfn(d, idx, mfn); - grant_write_unlock(gt); - - return rc; -} - -int gnttab_get_status_frame(struct domain *d, unsigned long idx, - mfn_t *mfn) -{ - struct grant_table *gt = d->grant_table; - int rc; - - grant_write_lock(gt); - rc = (gt->gt_version == 2) ? - gnttab_get_status_frame_mfn(d, idx, mfn) : -EINVAL; - grant_write_unlock(gt); - - return rc; -} - static void gnttab_usage_print(struct domain *rd) { int first = 1; diff --git a/xen/common/memory.c b/xen/common/memory.c index 714077c1e5..dc3a7248e3 100644 --- a/xen/common/memory.c +++ b/xen/common/memory.c @@ -1007,44 +1007,6 @@ static long xatp_permission_check(struct domain *d, unsigned int space) return xsm_add_to_physmap(XSM_TARGET, current->domain, d); } -static int acquire_grant_table(struct domain *d, unsigned int id, - unsigned long frame, - unsigned int nr_frames, - xen_pfn_t mfn_list[]) -{ - unsigned int i = nr_frames; - - /* Iterate backwards in case table needs to grow */ - while ( i-- != 0 ) - { - mfn_t mfn = INVALID_MFN; - int rc; - - switch ( id ) - { - case XENMEM_resource_grant_table_id_shared: - rc = gnttab_get_shared_frame(d, frame + i, &mfn); - break; - - case XENMEM_resource_grant_table_id_status: - rc = gnttab_get_status_frame(d, frame + i, &mfn); - break; - - default: - rc = -EINVAL; - break; - } - - if ( rc ) - return rc; - - ASSERT(!mfn_eq(mfn, INVALID_MFN)); - mfn_list[i] = mfn_x(mfn); - } - - return 0; -} - static int acquire_resource( XEN_GUEST_HANDLE_PARAM(xen_mem_acquire_resource_t) arg) { @@ -1091,8 +1053,8 @@ static int acquire_resource( switch ( xmar.type ) { case XENMEM_resource_grant_table: - rc = acquire_grant_table(d, xmar.id, xmar.frame, xmar.nr_frames, - mfn_list); + rc = gnttab_acquire_resource(d, xmar.id, xmar.frame, xmar.nr_frames, + mfn_list); break; default: diff --git a/xen/include/xen/grant_table.h b/xen/include/xen/grant_table.h index 98603604b8..5a2c75b880 100644 --- a/xen/include/xen/grant_table.h +++ b/xen/include/xen/grant_table.h @@ -56,10 +56,10 @@ int mem_sharing_gref_to_gfn(struct grant_table *gt, grant_ref_t ref, int gnttab_map_frame(struct domain *d, unsigned long idx, gfn_t gfn, mfn_t *mfn); -int gnttab_get_shared_frame(struct domain *d, unsigned long idx, - mfn_t *mfn); -int gnttab_get_status_frame(struct domain *d, unsigned long idx, - mfn_t *mfn); + +int gnttab_acquire_resource( + struct domain *d, unsigned int id, unsigned long frame, + unsigned int nr_frames, xen_pfn_t mfn_list[]); #else @@ -93,14 +93,9 @@ static inline int gnttab_map_frame(struct domain *d, unsigned long idx, return -EINVAL; } -static inline int gnttab_get_shared_frame(struct domain *d, unsigned long idx, - mfn_t *mfn) -{ - return -EINVAL; -} - -static inline int gnttab_get_status_frame(struct domain *d, unsigned long idx, - mfn_t *mfn) +static inline int gnttab_acquire_resource( + struct domain *d, unsigned int id, unsigned long frame, + unsigned int nr_frames, xen_pfn_t mfn_list[]) { return -EINVAL; }