hamza.kesraoui/sst-linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

nvme-pci: skip CMB blocks incompatible with PCI P2P DMA

Browse Source 
[ Upstream commit 56cf7ef0d490b28fad8f8629fc135c5ab7c9f54e ]

The PCI P2PDMA code will register the CMB block to the memory
hot-plugging subsystem, which have an alignment requirement. Memory
blocks that do not satisfy this alignment requirement (usually 2MB) will
lead to a WARNING from memory hotplugging.

Verify the CMB block's address and size against the alignment and only
try to send CMB blocks compatible with it to prevent this warning.

Tested on Intel DC D4502 SSD, which has a 512K CMB block that is too
small for memory hotplugging (thus PCI P2PDMA).

Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Icenowy Zheng 2025-02-13 01:04:44 +08:00 committed by Greg Kroah-Hartman
parent 159ef31d18
commit ff0c8508eb
1 changed files with 12 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
drivers/nvme/host/pci.c
View File

@ -1928,6 +1928,18 @@ static void nvme_map_cmb(struct nvme_dev *dev)
if (offset > bar_size)
return;
/*
* Controllers may support a CMB size larger than their BAR, for
* example, due to being behind a bridge. Reduce the CMB to the
* reported size of the BAR
*/
size = min(size, bar_size - offset);
if (!IS_ALIGNED(size, memremap_compat_align()) ||
!IS_ALIGNED(pci_resource_start(pdev, bar),
memremap_compat_align()))
return;
/*
* Tell the controller about the host side address mapping the CMB,
* and enable CMB decoding for the NVMe 1.4+ scheme:
@ -1938,14 +1950,6 @@ static void nvme_map_cmb(struct nvme_dev *dev)
dev->bar + NVME_REG_CMBMSC);
}
/*
* Controllers may support a CMB size larger than their BAR,
* for example, due to being behind a bridge. Reduce the CMB to
* the reported size of the BAR
*/
if (size > bar_size - offset)
size = bar_size - offset;
if (pci_p2pdma_add_resource(pdev, bar, size, offset)) {
dev_warn(dev->ctrl.device,
"failed to register the CMB\n");