Re: [PATCH] tpm: tpm2-space: Resize session and context buffers dynamically

[Jarkko Sakkinen]

On Thu, Jun 25, 2020 at 08:13:09AM -0400, Stefan Berger wrote:
> On 6/25/20 12:24 AM, Jarkko Sakkinen wrote:
> > Re-allocate context and session buffers when needed. Scale them in page
> > increments so that the reallocation is only seldomly required, and thus
> > causes minimal stress to the system. Add a static maximum limit of four
> > pages for buffer sizes.
> > 
> > Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
> > Suggested-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> > ---
> > Tested only for compilation.
> >   drivers/char/tpm/tpm2-space.c | 80 ++++++++++++++++++++++++-----------
> >   include/linux/tpm.h           |  6 ++-
> >   2 files changed, 59 insertions(+), 27 deletions(-)
> > 
> > diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
> > index 982d341d8837..acb9e82bf9e8 100644
> > --- a/drivers/char/tpm/tpm2-space.c
> > +++ b/drivers/char/tpm/tpm2-space.c
> > @@ -15,6 +15,8 @@
> >   #include <asm/unaligned.h>
> >   #include "tpm.h"
> > +#define TPM2_SPACE_MAX_BUFFER_SIZE	(4 * PAGE_SIZE)
> 
> PAGE_SIZE is 64k on ppc64. Rather use 4 * 4096?

Better to then just put it as 16384.

/Jarkko