linux-kernel - [PATCH v5 4/7] iommu/vt-d: Handle RMRR with PCI bridge device scopes

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Message-Id: <20190528115025.17194-5-eric.auger@redhat.com>
Date:   Tue, 28 May 2019 13:50:22 +0200
From:   Eric Auger <eric.auger@...hat.com>
To:     eric.auger.pro@...il.com, eric.auger@...hat.com, joro@...tes.org,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        dwmw2@...radead.org, robin.murphy@....com
Cc:     alex.williamson@...hat.com, shameerali.kolothum.thodi@...wei.com,
        jean-philippe.brucker@....com
Subject: [PATCH v5 4/7] iommu/vt-d: Handle RMRR with PCI bridge device scopes

When reading the vtd specification and especially the
Reserved Memory Region Reporting Structure chapter,
it is not obvious a device scope element cannot be a
PCI-PCI bridge, in which case all downstream ports are
likely to access the reserved memory region. Let's handle
this case in device_has_rmrr.

Fixes: ea2447f700ca ("intel-iommu: Prevent devices with RMRRs from being placed into SI Domain")

Signed-off-by: Eric Auger <eric.auger@...hat.com>

---

v1 -> v2:
- is_downstream_to_pci_bridge helper introduced in a separate patch
---
 drivers/iommu/intel-iommu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 879f11c82b05..35508687f178 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -2910,7 +2910,8 @@ static bool device_has_rmrr(struct device *dev)
 		 */
 		for_each_active_dev_scope(rmrr->devices,
 					  rmrr->devices_cnt, i, tmp)
-			if (tmp == dev) {
+			if (tmp == dev ||
+			    is_downstream_to_pci_bridge(dev, tmp)) {
 				rcu_read_unlock();
 				return true;
 			}
-- 
2.20.1