Am 24. Oktober 2017 20:15:12 MESZ schrieb Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>: >On Tue, Oct 24, 2017 at 10:02:00AM -0700, Dmitry Torokhov wrote: >> On Tue, Oct 24, 2017 at 9:11 AM, Jason Gunthorpe >> <jgunthorpe@xxxxxxxxxxxxxxxxxxxx> wrote: >> > On Tue, Oct 24, 2017 at 09:37:33PM +0530, PrasannaKumar >Muralidharan wrote: >> >> Hi Jason, >> >> >> >> On 24 October 2017 at 21:25, Jason Gunthorpe >> >> <jgunthorpe@xxxxxxxxxxxxxxxxxxxx> wrote: >> >> > On Tue, Oct 24, 2017 at 09:21:15PM +0530, PrasannaKumar >Muralidharan wrote: >> >> > >> >> >> Please check the RFC [1]. It does use chip id. The rfc has >issues and >> >> >> has to be fixed but still there could be users of the API. >> >> >> >> >> >> 1. https://www.spinics.net/lists/linux-crypto/msg28282.html >> >> > >> >> > That patch isn't safe at all. You need to store a kref to th >chip in >> >> > the hwrng, not parse a string. >> >> >> >> The drivers/char/hw_random/tpm-rng.c module does not store the >chip >> >> reference so I guess the usage is safe. >> > >> > It is using the default TPM, it is always safe to use the default >tpm. >> >> tpm-rng is abomination that should be kicked out as soon as possible. >> It wrecks havoc with the power management (TPM chip drivers may go >> into suspend state, but tpm_rng does not do any power management and >> happily forwards requests to suspended hardware) and may be available >> when there is no TPM at all yet (the drivers have not been probed >yet, >> or have gotten a deferral, etc). >> >> TPM core should register HWRNGs when chips are ready. >> >> Thanks. >> >> -- >> Dmitry > >I'm fine to review a two patch set where: > >1. Patch 1 removes the existing TPM rng driver >2. Patch 2 makes the TPM driver as rng producer Yes, but tpm must be kept a hwrng source. This is imho an important use case. > >Unrelate to patch that I'm proposing now but this sounds sensible. > >/Jarkko -- Sent from my mobile
