linux-kernel - [PATCH 1/2] iommu/vt-d: Check capability before disabling protected memory

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 for Android: free password hash cracker in your pocket

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

Date:   Wed, 20 Mar 2019 09:58:33 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     Joerg Roedel <joro@...tes.org>,
        David Woodhouse <dwmw2@...radead.org>
Cc:     ashok.raj@...el.com, jacob.jun.pan@...el.com, kevin.tian@...el.com,
        yi.l.liu@...el.com, iommu@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org, Lu Baolu <baolu.lu@...ux.intel.com>,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>,
        mark gross <mgross@...el.com>
Subject: [PATCH 1/2] iommu/vt-d: Check capability before disabling protected memory

The spec states in 10.4.16 that the Protected Memory Enable
Register should be treated as read-only for implementations
not supporting protected memory regions (PLMR and PHMR fields
reported as Clear in the Capability register).

Cc: Jacob Pan <jacob.jun.pan@...ux.intel.com>
Cc: mark gross <mgross@...el.com>
Suggested-by: Ashok Raj <ashok.raj@...el.com>
Fixes: f8bab73515ca5 ("intel-iommu: PMEN support")
Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
---
 drivers/iommu/intel-iommu.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 87274b54febd..f002d47d2f27 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1538,6 +1538,9 @@ static void iommu_disable_protect_mem_regions(struct intel_iommu *iommu)
 	u32 pmen;
 	unsigned long flags;
 
+	if (!cap_plmr(iommu->cap) && !cap_phmr(iommu->cap))
+		return;
+
 	raw_spin_lock_irqsave(&iommu->register_lock, flags);
 	pmen = readl(iommu->reg + DMAR_PMEN_REG);
 	pmen &= ~DMA_PMEN_EPM;
-- 
2.17.1