]> git.proxmox.com Git - mirror_ubuntu-disco-kernel.git/commit
iommu/amd: Fix the left value check of cmd buffer
authorHuang Rui <ray.huang@amd.com>
Mon, 12 Dec 2016 12:28:26 +0000 (07:28 -0500)
committerJoerg Roedel <jroedel@suse.de>
Wed, 4 Jan 2017 14:22:22 +0000 (15:22 +0100)
commit432abf68a79332282329286d190e21fe3ac02a31
tree2acb338f4341a7deae4fdf99579f4b7528cf55cc
parent65ca7f5f7d1cdde6c25172fe6107cd16902f826f
iommu/amd: Fix the left value check of cmd buffer

The generic command buffer entry is 128 bits (16 bytes), so the offset
of tail and head pointer should be 16 bytes aligned and increased with
0x10 per command.

When cmd buf is full, head = (tail + 0x10) % CMD_BUFFER_SIZE.

So when left space of cmd buf should be able to store only two
command, we should be issued one COMPLETE_WAIT additionally to wait
all older commands completed. Then the left space should be increased
after IOMMU fetching from cmd buf.

So left check value should be left <= 0x20 (two commands).

Signed-off-by: Huang Rui <ray.huang@amd.com>
Fixes: ac0ea6e92b222 ('x86/amd-iommu: Improve handling of full command buffer')
Signed-off-by: Joerg Roedel <jroedel@suse.de>
drivers/iommu/amd_iommu.c