linux-kernel - [PATCH AUTOSEL 4.19 037/172] PCI: vmd: Filter resource type bits from shadow register

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Date:   Wed, 17 Jun 2020 21:20:03 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Jon Derrick <jonathan.derrick@...el.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Sasha Levin <sashal@...nel.org>, linux-pci@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 037/172] PCI: vmd: Filter resource type bits from shadow register

From: Jon Derrick <jonathan.derrick@...el.com>

[ Upstream commit 3e5095eebe015d5a4d566aa5e03c8621add5f0a7 ]

Versions of VMD with the Host Physical Address shadow register use this
register to calculate the bus address offset needed to do guest
passthrough of the domain. This register shadows the Host Physical
Address registers including the resource type bits. After calculating
the offset, the extra resource type bits lead to the VMD resources being
over-provisioned at the front and under-provisioned at the back.

Example:
pci 10000:80:02.0: reg 0x10: [mem 0xf801fffc-0xf803fffb 64bit]

Expected:
pci 10000:80:02.0: reg 0x10: [mem 0xf8020000-0xf803ffff 64bit]

If other devices are mapped in the over-provisioned front, it could lead
to resource conflict issues with VMD or those devices.

Link: https://lore.kernel.org/r/20200528030240.16024-3-jonathan.derrick@intel.com
Fixes: a1a30170138c9 ("PCI: vmd: Fix shadow offsets to reflect spec changes")
Signed-off-by: Jon Derrick <jonathan.derrick@...el.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/pci/controller/vmd.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
index ab36e5ca1aca..153abbc9412d 100644
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -617,9 +617,11 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
 			if (!membar2)
 				return -ENOMEM;
 			offset[0] = vmd->dev->resource[VMD_MEMBAR1].start -
-					readq(membar2 + MB2_SHADOW_OFFSET);
+					(readq(membar2 + MB2_SHADOW_OFFSET) &
+					 PCI_BASE_ADDRESS_MEM_MASK);
 			offset[1] = vmd->dev->resource[VMD_MEMBAR2].start -
-					readq(membar2 + MB2_SHADOW_OFFSET + 8);
+					(readq(membar2 + MB2_SHADOW_OFFSET + 8) &
+					 PCI_BASE_ADDRESS_MEM_MASK);
 			pci_iounmap(vmd->dev, membar2);
 		}
 	}
-- 
2.25.1