From patchwork Fri Sep 11 08:20:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Durrant X-Patchwork-Id: 11769929 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 92751746 for ; Fri, 11 Sep 2020 08:22:15 +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 4D98A221E3 for ; Fri, 11 Sep 2020 08:22:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=xen.org header.i=@xen.org header.b="o+Ld7YxF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4D98A221E3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xen.org 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 1kGeIe-0006n0-QW; Fri, 11 Sep 2020 08:20:52 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kGeId-0006hc-J1 for xen-devel@lists.xenproject.org; Fri, 11 Sep 2020 08:20:51 +0000 X-Inumbo-ID: 30c06ea5-4f8e-4e92-9547-2f1dfa512cb1 Received: from mail.xenproject.org (unknown [104.130.215.37]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 30c06ea5-4f8e-4e92-9547-2f1dfa512cb1; Fri, 11 Sep 2020 08:20:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Content-Transfer-Encoding:MIME-Version:References: In-Reply-To:Message-Id:Date:Subject:Cc:To:From; bh=6V76Q1js+MJI/MnngmySvDNGdA9OgOS346gnP058fqs=; b=o+Ld7YxFFgX4IfK9bOiDfKGp0g aWkOG44sZLFAvw+wGde/iglALtfXee1S+0HDw21BN/mVDyJmKatOHCyFylscHEr8yW7Yk+ZDTeknQ 9axDG7+avaSjlZSnSlvmNbzfyXpzG+myr21QG6XHXqtjrRzO8aHDRtu2RvMYvNHtROLc=; Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kGeIV-0002te-5f; Fri, 11 Sep 2020 08:20:43 +0000 Received: from host86-176-94-160.range86-176.btcentralplus.com ([86.176.94.160] helo=u2f063a87eabd5f.home) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kGeIU-0006YQ-U1; Fri, 11 Sep 2020 08:20:43 +0000 From: Paul Durrant To: xen-devel@lists.xenproject.org Cc: Paul Durrant , Jan Beulich , Andrew Cooper , George Dunlap , Ian Jackson , Julien Grall , Stefano Stabellini , Wei Liu Subject: [PATCH v8 6/8] common/grant_table: batch flush I/O TLB Date: Fri, 11 Sep 2020 09:20:30 +0100 Message-Id: <20200911082032.1466-7-paul@xen.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200911082032.1466-1-paul@xen.org> References: <20200911082032.1466-1-paul@xen.org> 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: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" From: Paul Durrant This patch avoids calling iommu_iotlb_flush() for each individual GNTTABOP and instead calls iommu_iotlb_flush_all() at the end of a batch. This should mean non-singleton map/unmap operations perform better. NOTE: A batch is the number of operations done before a pre-emption check and, in the case of unmap, a TLB flush. Suggested-by: Jan Beulich Signed-off-by: Paul Durrant Reviewed-by: Jan Beulich --- Cc: Andrew Cooper Cc: George Dunlap Cc: Ian Jackson Cc: Julien Grall Cc: Stefano Stabellini Cc: Wei Liu v6: - Fix spelling of 'preemption' - Drop unneeded 'currd' stack variable v5: - Add batching to gnttab_map_grant_ref() to handle flushing before pre- emption check - Maintain per-op flushing in the case of singletons v3: - New in v3 --- xen/common/grant_table.c | 199 ++++++++++++++++++++++++++------------- 1 file changed, 133 insertions(+), 66 deletions(-) diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c index beb6b2d40d..1e3d7a2d33 100644 --- a/xen/common/grant_table.c +++ b/xen/common/grant_table.c @@ -241,7 +241,13 @@ struct gnttab_unmap_common { grant_ref_t ref; }; -/* Number of unmap operations that are done between each tlb flush */ +/* Number of map operations that are done between each preemption check */ +#define GNTTAB_MAP_BATCH_SIZE 32 + +/* + * Number of unmap operations that are done between each tlb flush and + * preemption check. + */ #define GNTTAB_UNMAP_BATCH_SIZE 32 @@ -979,7 +985,7 @@ static unsigned int mapkind( static void map_grant_ref( - struct gnttab_map_grant_ref *op) + struct gnttab_map_grant_ref *op, bool do_flush, unsigned int *flush_flags) { struct domain *ld, *rd, *owner = NULL; struct grant_table *lgt, *rgt; @@ -1229,12 +1235,11 @@ map_grant_ref( if ( kind ) { dfn_t dfn = _dfn(mfn_x(mfn)); - unsigned int flush_flags = 0; int err; - err = iommu_map(ld, dfn, mfn, 1, kind, &flush_flags); - if ( !err ) - err = iommu_iotlb_flush(ld, dfn, 1, flush_flags); + err = iommu_map(ld, dfn, mfn, 1, kind, flush_flags); + if ( do_flush && !err ) + err = iommu_iotlb_flush(ld, dfn, 1, *flush_flags); if ( err ) { double_gt_unlock(lgt, rgt); @@ -1319,29 +1324,59 @@ static long gnttab_map_grant_ref( XEN_GUEST_HANDLE_PARAM(gnttab_map_grant_ref_t) uop, unsigned int count) { - int i; - struct gnttab_map_grant_ref op; + unsigned int done = 0; + int rc = 0; - for ( i = 0; i < count; i++ ) + while ( count ) { - if ( i && hypercall_preempt_check() ) - return i; + unsigned int i, c = min_t(unsigned int, count, GNTTAB_MAP_BATCH_SIZE); + unsigned int flush_flags = 0; - if ( unlikely(__copy_from_guest_offset(&op, uop, i, 1)) ) - return -EFAULT; + for ( i = 0; i < c; i++ ) + { + struct gnttab_map_grant_ref op; - map_grant_ref(&op); + if ( unlikely(__copy_from_guest(&op, uop, 1)) ) + { + rc = -EFAULT; + break; + } - if ( unlikely(__copy_to_guest_offset(uop, i, &op, 1)) ) - return -EFAULT; + map_grant_ref(&op, c == 1, &flush_flags); + + if ( unlikely(__copy_to_guest(uop, &op, 1)) ) + { + rc = -EFAULT; + break; + } + + guest_handle_add_offset(uop, 1); + } + + if ( c > 1 ) + { + int err = iommu_iotlb_flush_all(current->domain, flush_flags); + + if ( !rc ) + rc = err; + } + + if ( rc ) + break; + + count -= c; + done += c; + + if ( count && hypercall_preempt_check() ) + return done; } - return 0; + return rc; } static void unmap_common( - struct gnttab_unmap_common *op) + struct gnttab_unmap_common *op, bool do_flush, unsigned int *flush_flags) { domid_t dom; struct domain *ld, *rd; @@ -1485,22 +1520,20 @@ unmap_common( { unsigned int kind; dfn_t dfn = _dfn(mfn_x(op->mfn)); - unsigned int flush_flags = 0; int err = 0; double_gt_lock(lgt, rgt); kind = mapkind(lgt, rd, op->mfn); if ( !kind ) - err = iommu_unmap(ld, dfn, 1, &flush_flags); + err = iommu_unmap(ld, dfn, 1, flush_flags); else if ( !(kind & MAPKIND_WRITE) ) - err = iommu_map(ld, dfn, op->mfn, 1, IOMMUF_readable, - &flush_flags); + err = iommu_map(ld, dfn, op->mfn, 1, IOMMUF_readable, flush_flags); double_gt_unlock(lgt, rgt); - if ( !err ) - err = iommu_iotlb_flush(ld, dfn, 1, flush_flags); + if ( do_flush && !err ) + err = iommu_iotlb_flush(ld, dfn, 1, *flush_flags); if ( err ) rc = GNTST_general_error; } @@ -1599,8 +1632,8 @@ unmap_common_complete(struct gnttab_unmap_common *op) static void unmap_grant_ref( - struct gnttab_unmap_grant_ref *op, - struct gnttab_unmap_common *common) + struct gnttab_unmap_grant_ref *op, struct gnttab_unmap_common *common, + bool do_flush, unsigned int *flush_flags) { common->host_addr = op->host_addr; common->dev_bus_addr = op->dev_bus_addr; @@ -1612,7 +1645,7 @@ unmap_grant_ref( common->rd = NULL; common->mfn = INVALID_MFN; - unmap_common(common); + unmap_common(common, do_flush, flush_flags); op->status = common->status; } @@ -1621,31 +1654,55 @@ static long gnttab_unmap_grant_ref( XEN_GUEST_HANDLE_PARAM(gnttab_unmap_grant_ref_t) uop, unsigned int count) { - int i, c, partial_done, done = 0; - struct gnttab_unmap_grant_ref op; - struct gnttab_unmap_common common[GNTTAB_UNMAP_BATCH_SIZE]; + struct domain *currd = current->domain; + unsigned int done = 0; + int rc = 0; - while ( count != 0 ) + while ( count ) { - c = min(count, (unsigned int)GNTTAB_UNMAP_BATCH_SIZE); - partial_done = 0; + struct gnttab_unmap_common common[GNTTAB_UNMAP_BATCH_SIZE]; + unsigned int i, c, partial_done = 0; + unsigned int flush_flags = 0; + + c = min_t(unsigned int, count, GNTTAB_UNMAP_BATCH_SIZE); for ( i = 0; i < c; i++ ) { + struct gnttab_unmap_grant_ref op; + if ( unlikely(__copy_from_guest(&op, uop, 1)) ) - goto fault; - unmap_grant_ref(&op, &common[i]); + { + rc = -EFAULT; + break; + } + + unmap_grant_ref(&op, &common[i], c == 1, &flush_flags); ++partial_done; + if ( unlikely(__copy_field_to_guest(uop, &op, status)) ) - goto fault; + { + rc = -EFAULT; + break; + } + guest_handle_add_offset(uop, 1); } - gnttab_flush_tlb(current->domain); + gnttab_flush_tlb(currd); + if ( c > 1 ) + { + int err = iommu_iotlb_flush_all(currd, flush_flags); + + if ( !rc ) + rc = err; + } for ( i = 0; i < partial_done; i++ ) unmap_common_complete(&common[i]); + if ( rc ) + break; + count -= c; done += c; @@ -1653,20 +1710,13 @@ gnttab_unmap_grant_ref( return done; } - return 0; - -fault: - gnttab_flush_tlb(current->domain); - - for ( i = 0; i < partial_done; i++ ) - unmap_common_complete(&common[i]); - return -EFAULT; + return rc; } static void unmap_and_replace( - struct gnttab_unmap_and_replace *op, - struct gnttab_unmap_common *common) + struct gnttab_unmap_and_replace *op, struct gnttab_unmap_common *common, + bool do_flush, unsigned int *flush_flags) { common->host_addr = op->host_addr; common->new_addr = op->new_addr; @@ -1678,7 +1728,7 @@ unmap_and_replace( common->rd = NULL; common->mfn = INVALID_MFN; - unmap_common(common); + unmap_common(common, do_flush, flush_flags); op->status = common->status; } @@ -1686,31 +1736,55 @@ static long gnttab_unmap_and_replace( XEN_GUEST_HANDLE_PARAM(gnttab_unmap_and_replace_t) uop, unsigned int count) { - int i, c, partial_done, done = 0; - struct gnttab_unmap_and_replace op; - struct gnttab_unmap_common common[GNTTAB_UNMAP_BATCH_SIZE]; + struct domain *currd = current->domain; + unsigned int done = 0; + int rc = 0; - while ( count != 0 ) + while ( count ) { - c = min(count, (unsigned int)GNTTAB_UNMAP_BATCH_SIZE); - partial_done = 0; + struct gnttab_unmap_common common[GNTTAB_UNMAP_BATCH_SIZE]; + unsigned int i, c, partial_done = 0; + unsigned int flush_flags = 0; + + c = min_t(unsigned int, count, GNTTAB_UNMAP_BATCH_SIZE); for ( i = 0; i < c; i++ ) { + struct gnttab_unmap_and_replace op; + if ( unlikely(__copy_from_guest(&op, uop, 1)) ) - goto fault; - unmap_and_replace(&op, &common[i]); + { + rc = -EFAULT; + break; + } + + unmap_and_replace(&op, &common[i], c == 1, &flush_flags); ++partial_done; + if ( unlikely(__copy_field_to_guest(uop, &op, status)) ) - goto fault; + { + rc = -EFAULT; + break; + } + guest_handle_add_offset(uop, 1); } - gnttab_flush_tlb(current->domain); + gnttab_flush_tlb(currd); + if ( c > 1 ) + { + int err = iommu_iotlb_flush_all(currd, flush_flags); + + if ( !rc ) + rc = err; + } for ( i = 0; i < partial_done; i++ ) unmap_common_complete(&common[i]); + if ( rc ) + break; + count -= c; done += c; @@ -1718,14 +1792,7 @@ gnttab_unmap_and_replace( return done; } - return 0; - -fault: - gnttab_flush_tlb(current->domain); - - for ( i = 0; i < partial_done; i++ ) - unmap_common_complete(&common[i]); - return -EFAULT; + return rc; } static int