On Tue, Aug 21, 2018 at 04:57:03PM +0100, David Howells wrote: > Provide a misc device file (/dev/tpm_emul) by which a userspace TPM emulator > can set up a virtual TPM device under the control of the TPM frontend. The > way this works is: > > (1) The emulator opens /dev/tpm_emul which is provided by the tpm_user > driver. > > (2) tpm_user registers a TPM device and the tpm driver creates a /dev/tpmN > misc device for the trousers package and suchlike to access. > > (3) The emulator sits in read() on the emulator device waiting for a command > to come through. > > (4) tpm_user passes requests from /dev/tpmN to the emulator's read() call. > > (5) The emulator processes the request. > > (6) The emulator either write()'s the reply or calls ioctl(fd,0,0) to cancel > the command. > > (7) The emulator goes back to read() to wait for the next command. > > (8) tpm_user passes the reply back to the tpm driver which passes it back to > /dev/tpmN. > > When the emulator closes /dev/tpm_emul, the TPM driver is unregistered and the > /dev/tpmN misc device is then removed. Any outstanding requests are aborted > and -EIO will be returned from then on. Multiple TPMs can be registered. > > Signed-off-by: David Howells <dhowells@xxxxxxxxxx> > --- > > drivers/char/tpm/Kconfig | 13 + > drivers/char/tpm/Makefile | 1 > drivers/char/tpm/tpm_user_emul.c | 672 ++++++++++++++++++++++++++++++++++++++ > include/linux/wait.h | 11 + > 4 files changed, 697 insertions(+) > create mode 100644 drivers/char/tpm/tpm_user_emul.c This looks to duplicate the vtpm stuff... Jason
