linux-kernel - [PATCH 1/1] iommu/vt-d: Allow zero SAGAW if second-stage not supported

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20230318024824.124542-1-baolu.lu@linux.intel.com>
Date:   Sat, 18 Mar 2023 10:48:24 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     iommu@...ts.linux.dev
Cc:     Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>,
        Kevin Tian <kevin.tian@...el.com>,
        Raghunathan Srinivasan <raghunathan.srinivasan@...el.com>,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>,
        linux-kernel@...r.kernel.org, Lu Baolu <baolu.lu@...ux.intel.com>
Subject: [PATCH 1/1] iommu/vt-d: Allow zero SAGAW if second-stage not supported

The VT-d spec states (section 11.4.2) that hardware implementations
reporting second-stage translation support (SSTS) field as Clear also
report the SAGAW field as 0. Reflect this in the sanity check of
alloc_iommu().

Fixes: 792fb43ce2c9 ("iommu/vt-d: Enable Intel IOMMU scalable mode by default")
Suggested-by: Raghunathan Srinivasan <raghunathan.srinivasan@...el.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>
Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
---
 drivers/iommu/intel/dmar.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
index 6acfe879589c..23828d189c2a 100644
--- a/drivers/iommu/intel/dmar.c
+++ b/drivers/iommu/intel/dmar.c
@@ -1071,7 +1071,8 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)
 	}
 
 	err = -EINVAL;
-	if (cap_sagaw(iommu->cap) == 0) {
+	if (!cap_sagaw(iommu->cap) &&
+	    (!ecap_smts(iommu->ecap) || ecap_slts(iommu->ecap))) {
 		pr_info("%s: No supported address widths. Not attempting DMA translation.\n",
 			iommu->name);
 		drhd->ignored = 1;
-- 
2.34.1