On 4/15/20 4:35 AM, Jingqi Liu wrote:
For device dax (e.g., /dev/dax0.0), the NUM of 'align=NUM' option
needs to match the alignment requirement of the device dax.
It must be larger than or equal to the 'align' of device dax.
Signed-off-by: Jingqi Liu <address@hidden>
---
docs/nvdimm.txt | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt
index 362e99109e..3c7b6dab5f 100644
--- a/docs/nvdimm.txt
+++ b/docs/nvdimm.txt
@@ -132,6 +132,15 @@ address to the page size (getpagesize(2)) by default. However, some
types of backends may require an alignment different than the page
size. In that case, QEMU v2.12.0 and later provide 'align' option to
memory-backend-file to allow users to specify the proper alignment.
+For device dax (e.g., /dev/dax0.0), this alignment needs to match the
+alignment requirement of the device dax. The NUM of 'align=NUM' option
+must be larger than or equal to the 'align' of device dax.
+We can use the following command to show the 'align' of device dax.
+
+ ndctl list -X
+
+In order to get the proper 'align' of device dax, you need to install
+the library 'libdaxctl'.
For example, device dax require the 2 MB alignment, so we can use
following QEMU command line options to use it (/dev/dax0.0) as the
Given that this series introduces support for libdaxctl, perhaps suggesting in
the docs how you can also query the @align with daxctl tool? e.g.
"We can one of the following commands to show the 'align' of device dax:
ndctl list -X
daxctl list -R"