On 4/6/22 10:19, Bean Huo wrote:
On Wed, 2022-04-06 at 12:22 +0100, Alex Bennée wrote:
Bean Huo <huobean@xxxxxxxxx> writes:
On Tue, 2022-04-05 at 16:43 +0100, Alex Bennée wrote:
Bean Huo <huobean@xxxxxxxxx> writes:
Hi Alex,
Thanks for this unified RPMB interface, I wanted to verify this
on
our
UFS, it seems you didn't add the UFS access interface in this
version
from your userspace tools, right?
No I didn't but it should be easy enough to add some function
pointer
redirection everywhere one of the op_* functions calls a vrpmb_*
function. Do you already have a UFS RPMB device driver?
Hi Alex,
Thanks for your feedback.
We now access UFS RPMB through the RPMB LUN BSG device, RPMB is a
well-
known LU and we have a userspace tool to access it.
I see that if we're going to use your interface, "static struct
rpmb_ops" should be registered from a lower-level driver, for
example
in a UFS driver, yes there should be no problem with this
registration,
but I don't know with the current way Compared, what are the
advantages
to add a driver. maybe the main advantage is that we will have an
unified user space tool for RPMB. right?
Pretty much. The main issue for virtio-rpmb is it doesn't really fit
neatly into the block stack because all it does is the RPMB part so a
non-block orientate API makes sense.
Can you point be to where the UFS driver does it's current RPMB
stuff?
It's the SCSI BSG driver, in fact, we don't have a dedicated UFS RPMB
driver in the kernel. RPMB is a well known LU, we are using userspace
tools to issue SCSI commands directly to the UFS RPMB LU via ioctl()
from the BSG device node in the /dev/sg/ folder.
Here is the BSG part of the code in the userspace tools:
io_hdr_v4.guard = 'Q';
io_hdr_v4.protocol = BSG_PROTOCOL_SCSI;
io_hdr_v4.subprotocol = BSG_SUB_PROTOCOL_SCSI_CMD;
io_hdr_v4.response = (__u64)sense_buffer;
io_hdr_v4.max_response_len = SENSE_BUFF_LEN;
io_hdr_v4.request_len = cmd_len;
io_hdr_v4.request = (__u64)cdb;
ioctl(fd, SG_IO, &io_hdr_v4))
Hi Bean,
I'm not sure where the above comes from? The Android RPMB client uses
slightly different code. Additionally, the retry loop around the
submission of SG/IO commands is very important. See also the
check_sg_io_hdr() call in send_ufs_rpmb_req(). See also
https://cs.android.com/android/platform/superproject/+/master:system/core/trusty/storage/proxy/rpmb.c
Thanks,
Bart.
