From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755318Ab3ETH6j (ORCPT ); Mon, 20 May 2013 03:58:39 -0400 Received: from g4t0014.houston.hp.com ([15.201.24.17]:20196 "EHLO g4t0014.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754820Ab3ETH6i (ORCPT ); Mon, 20 May 2013 03:58:38 -0400 From: "Li, Zhen-Hua" To: Ingo Molnar , Joerg Roedel , Donald Dutile , Linn Crosetto , , Cc: "Li, Zhen-Hua" Subject: [PATCH 1/1] iommu: DMAR reporting table needs at least one DRHD Date: Mon, 20 May 2013 15:57:32 +0800 Message-Id: <1369036652-20022-1-git-send-email-zhen-hual@hp.com> X-Mailer: git-send-email 1.7.10.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In intel vt-d spec , chapter 8.1 , DMA Remapping Reporting Structure. In the end of the table, it says: Remapping Structures[] - A list of structures. The list will contain one or more DMA Remapping Hardware Unit Definition (DRHD) structures, and zero or more Reserved Memory Region Reporting (RMRR) and Root Port ATS Capability Reporting (ATSR) structures. These structures are described below. So, there should be at least one DRHD structure in DMA Remapping reporting table. If there is no DRHD found, a warning is necessary. Signed-off-by: Li, Zhen-Hua --- drivers/iommu/dmar.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c index a7967ce..4739211 100644 --- a/drivers/iommu/dmar.c +++ b/drivers/iommu/dmar.c @@ -309,6 +309,7 @@ parse_dmar_table(void) struct acpi_table_dmar *dmar; struct acpi_dmar_header *entry_header; int ret = 0; + int drhd_count = 0; /* * Do it again, earlier dmar_tbl mapping could be mapped with @@ -347,6 +348,7 @@ parse_dmar_table(void) switch (entry_header->type) { case ACPI_DMAR_TYPE_HARDWARE_UNIT: + drhd_count++; ret = dmar_parse_one_drhd(entry_header); break; case ACPI_DMAR_TYPE_RESERVED_MEMORY: @@ -371,6 +373,8 @@ parse_dmar_table(void) entry_header = ((void *)entry_header + entry_header->length); } + if (drhd_count == 0) + pr_warn("There is no DRHD structure."); return ret; } -- 1.7.10.4