From 4bdf260362b3be529d170b04662638fd6dc52241 Mon Sep 17 00:00:00 2001
From: Filippo Sironi <sironi@amazon.de>
Date: Wed, 10 Feb 2021 01:39:42 +0100
Subject: [PATCH] nvme: add 48-bit DMA address quirk for Amazon NVMe
 controllers

Some Amazon NVMe controllers do not follow the NVMe specification
and are limited to 48-bit DMA addresses.  Add a quirk to force
bounce buffering if needed and limit the IOVA allocation for these
devices.

This affects all current Amazon NVMe controllers that expose EBS
volumes (0x0061, 0x0065, 0x8061) and local instance storage
(0xcd00, 0xcd01, 0xcd02).

Signed-off-by: Filippo Sironi <sironi@amazon.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/nvme/host/nvme.h |  6 ++++++
 drivers/nvme/host/pci.c  | 21 ++++++++++++++++++++-
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 2efb87642d18..07b34175c6ce 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -144,6 +144,12 @@ enum nvme_quirks {
 	 * NVMe 1.3 compliance.
 	 */
 	NVME_QUIRK_NO_NS_DESC_LIST		= (1 << 15),
+
+	/*
+	 * The controller does not properly handle DMA addresses over
+	 * 48 bits.
+	 */
+	NVME_QUIRK_DMA_ADDRESS_BITS_48		= (1 << 16),
 };
 
 /*
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 5b78e68be9a1..0045c5edf629 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2367,13 +2367,16 @@ static int nvme_pci_enable(struct nvme_d
 {
 	int result = -ENOMEM;
 	struct pci_dev *pdev = to_pci_dev(dev->dev);
+	int dma_address_bits = 64;
 
 	if (pci_enable_device_mem(pdev))
 		return result;
 
 	pci_set_master(pdev);
 
-	if (dma_set_mask_and_coherent(dev->dev, DMA_BIT_MASK(64)))
+	if (dev->ctrl.quirks & NVME_QUIRK_DMA_ADDRESS_BITS_48)
+		dma_address_bits = 48;
+	if (dma_set_mask_and_coherent(dev->dev, DMA_BIT_MASK(dma_address_bits)))
 		goto disable;
 
 	if (readl(dev->bar + NVME_REG_CSTS) == -1) {
@@ -3274,6 +3277,18 @@ static const struct pci_device_id nvme_i
 		.driver_data = NVME_QUIRK_NO_DEEPEST_PS, },
 	{ PCI_DEVICE(0x2646, 0x2263),   /* KINGSTON A2000 NVMe SSD  */
 		.driver_data = NVME_QUIRK_NO_DEEPEST_PS, },
+	{ PCI_DEVICE(PCI_VENDOR_ID_AMAZON, 0x0061),
+		.driver_data = NVME_QUIRK_DMA_ADDRESS_BITS_48, },
+	{ PCI_DEVICE(PCI_VENDOR_ID_AMAZON, 0x0065),
+		.driver_data = NVME_QUIRK_DMA_ADDRESS_BITS_48, },
+	{ PCI_DEVICE(PCI_VENDOR_ID_AMAZON, 0x8061),
+		.driver_data = NVME_QUIRK_DMA_ADDRESS_BITS_48, },
+	{ PCI_DEVICE(PCI_VENDOR_ID_AMAZON, 0xcd00),
+		.driver_data = NVME_QUIRK_DMA_ADDRESS_BITS_48, },
+	{ PCI_DEVICE(PCI_VENDOR_ID_AMAZON, 0xcd01),
+		.driver_data = NVME_QUIRK_DMA_ADDRESS_BITS_48, },
+	{ PCI_DEVICE(PCI_VENDOR_ID_AMAZON, 0xcd02),
+		.driver_data = NVME_QUIRK_DMA_ADDRESS_BITS_48, },
 	{ PCI_DEVICE(PCI_VENDOR_ID_APPLE, 0x2001),
 		.driver_data = NVME_QUIRK_SINGLE_VECTOR },
 	{ PCI_DEVICE(PCI_VENDOR_ID_APPLE, 0x2003) },