Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753488AbaDDOlS (ORCPT ); Fri, 4 Apr 2014 10:41:18 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:31830 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753054AbaDDOlQ (ORCPT ); Fri, 4 Apr 2014 10:41:16 -0400 X-IronPort-AV: E=Sophos;i="4.97,795,1389744000"; d="scan'208";a="116822543" From: Roger Pau Monne To: , CC: Roger Pau Monne , Konrad Rzeszutek Wilk , David Vrabel , Boris Ostrovsky Subject: [PATCH] xen-blkback: only attach blkback if the required features are met Date: Fri, 4 Apr 2014 16:41:11 +0200 Message-ID: <1396622471-13114-1-git-send-email-roger.pau@citrix.com> X-Mailer: git-send-email 1.7.7.5 (Apple Git-26) MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-DLP: MIA2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Blkback cannot work properly on auto-translated guests if Xen doesn't update the IOMMU when performing grant maps/unmaps, so only attach if the newly introduced XENFEAT_hvm_gntmap_supports_iommu is found. Signed-off-by: Roger Pau Monné Cc: Konrad Rzeszutek Wilk Cc: David Vrabel Cc: Boris Ostrovsky --- drivers/block/xen-blkback/blkback.c | 12 ++++++++++++ include/xen/interface/features.h | 6 ++++++ 2 files changed, 18 insertions(+), 0 deletions(-) diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index 64c60ed..4c23ddd 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -1381,6 +1381,18 @@ static int __init xen_blkif_init(void) if (!xen_domain()) return -ENODEV; +#ifdef CONFIG_X86 + if (xen_feature(XENFEAT_auto_translated_physmap) && + !xen_feature(XENFEAT_hvm_gntmap_supports_iommu)) { + /* + * blkback cannot work properly on auto-translated guests + * if grant table mappings don't update the IOMMU entries. + */ + pr_debug(DRV_PFX "Disabling blkback because Xen is missing feature XENFEAT_hvm_gntmap_supports_iommu\n"); + return -ENODEV; + } +#endif /* CONFIG_X86 */ + rc = xen_blkif_interface_init(); if (rc) goto failed_init; diff --git a/include/xen/interface/features.h b/include/xen/interface/features.h index 131a6cc..d1e0f23 100644 --- a/include/xen/interface/features.h +++ b/include/xen/interface/features.h @@ -53,6 +53,12 @@ /* operation as Dom0 is supported */ #define XENFEAT_dom0 11 +/* + * If set, GNTTABOP_map_grant_ref sets the proper IOMMU mappings so the + * resulting mapped page can be used for IO with hardware devices. + */ +#define XENFEAT_hvm_gntmap_supports_iommu 12 + #define XENFEAT_NR_SUBMAPS 1 #endif /* __XEN_PUBLIC_FEATURES_H__ */ -- 1.7.7.5 (Apple Git-26) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/