On Thu, May 04, 2017 at 01:13:18PM -0400, Stefan Berger wrote:
On 05/04/2017 11:34 AM, Jason Gunthorpe wrote:Try and enable the feature, if it fails then there is no feature in
On Thu, May 04, 2017 at 10:56:25AM -0400, Stefan Berger wrote:Do you have an example driver that shows how to do this ? Can user space
Implement VTPM_PROXY_IOC_GET_SUPT_FLAGS ioctl to get the bitmaskyou might be better off just having a VTPM_PROXY_IO_ENABLE_FEATURE
of flags that the vtpm_proxy driver supports in the
VTPM_PROXY_IOC_NEW_DEV ioctl. This helps user space in deciding
which flags to set in that ioctl.
.feature = LOCALITY
query that feature?
This is the usual way to add new syscalls..
Well, if TIS hardware has some scheme I feel like the emulator uAPI shouldIf that fails then the feature is not supported, no real need for theWe could filter localities 5 and higher on the level of the driver (patch
query in that case.
Not sure about Jarkko's point on request/release locality.. Is there a
scenario where the emulator should fail the request locality?
2/3) since basically there are only 5 localities (0-4) in any TPM interface
today. The typical hardware locality 4 would be filtered by the emulator per
policy passed via command line, but I would allow it on the level of this
driver. An error message would be returned for any command executed in that
locality, unless the 'policy' allows it. Localities 0-3 should just be
selectable. The TPM TIS (in the hardware) implements some complicated scheme
when it comes to allowing the selection of a locality and I would say we
need none of that but just tell the vTPM proxy driver the locality (patch
2/3) in which the next command will be executed.
have enough fidelity to ecompass existing hardware, even if your
current emulator does not need it.
So allowing request_locality to fail from userspace seems reasonable.