Re: [PATCH v2] nvme-pci: Use PCI bus address for data/queues in CMB

From: Sagi Grimberg
Date: Wed Oct 11 2017 - 06:00:29 EST


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From b78f4164881125c4fecfdb87878d0120b2177c53 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@xxxxxx>
Date: Sun, 1 Oct 2017 09:37:35 +0200
Subject: nvme-pci: Use PCI bus address for data/queues in CMB

Currently, NVMe PCI host driver is programming CMB dma address as
I/O SQs addresses. This results in failures on systems where 1:1
outbound mapping is not used (example Broadcom iProc SOCs) because
CMB BAR will be progammed with PCI bus address but NVMe PCI EP will
try to access CMB using dma address.

To have CMB working on systems without 1:1 outbound mapping, we
program PCI bus address for I/O SQs instead of dma address. This
approach will work on systems with/without 1:1 outbound mapping.

Based on a report and previous patch from Abhishek Shah.

Fixes: 8ffaadf7 ("NVMe: Use CMB for the IO SQes if available")
Cc: stable@xxxxxxxxxxxxxxx
Reported-by: Abhishek Shah <abhishek.shah@xxxxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>

This looks good,

Reviewed-by: Sagi Grimberg <sagi@xxxxxxxxxxx>