On Fri, Apr 24, 2026 at 04:54:03PM -0400, Stefan Berger wrote: > > > On 4/23/26 6:43 AM, Arun Menon wrote: > > On Wed, Apr 08, 2026 at 11:34:54AM +0300, Jarkko Sakkinen wrote: > > > On Tue, Mar 24, 2026 at 06:11:11PM +0530, Arun Menon wrote: > > > > Hi Jarkko, > > > > > > > > On Tue, Mar 24, 2026 at 12:41:26PM +0200, Jarkko Sakkinen wrote: > > > > > On Tue, Mar 24, 2026 at 12:47:59PM +0530, Arun Menon wrote: > > > > > > The new version of TCG TPM v185 (currently under review [1]) > > > > > > supports > > > > > > sending data/commands in chunks for the CRB (Command Response > > > > > > Buffer) > > > > > > interface. This is in line with the initiative to support PQC > > > > > > algorithms. > > > > > > > > > > > > This series implements the logic to send and receive larger TPM > > > > > > cmd/rsp between the linux guest and the TPM backend in chunks. > > > > > > Currently, the TPM CRB driver is limited by the physical size of the > > > > > > MMIO window. When userspace attempts to send a payload that exceeds > > > > > > this > > > > > > size, the driver rejects it. > > > > > > > > > > > > This series introduces chunking support. The driver now checks the > > > > > > CRB > > > > > > interface capability for CRB_INTF_CAP_CRB_CHUNK. If supported by the > > > > > > backend, the driver will slice oversized commands into MMIO-sized > > > > > > chunks, signalling the backend via CRB_START_NEXT_CHUNK, and > > > > > > finalizing > > > > > > with CRB_START_INVOKE. Responses are also read back in a similar > > > > > > chunked > > > > > > manner. > > > > > > > > > > > > If the backend does not support chunking, the driver retains its > > > > > > legacy > > > > > > behaviour and enforces the standard size limits. > > > > > > > > > > > > This feature also requires the QEMU to interpret the data in chunks > > > > > > and > > > > > > forward it to the TPM backend and subsequently dispatch the TPM > > > > > > response > > > > > > in chunks back to the linux guest. This is implemented in [2] > > > > > > > > > > > > [1] > > > > > > https://trustedcomputinggroup.org/wp-content/uploads/PC-Client-Specific-Platform-TPM-Profile-for-TPM-2p0-v1p07_rc1_121225.pdf > > > > > > [2] > > > > > > https://lore.kernel.org/qemu-devel/[email protected]/ > > > > > > > > > > > > Arun Menon (4): > > > > > > tpm_crb: Add definition of TPM CRB chunking fields > > > > > > tpm_crb: Add new wrapper function to invoke start method > > > > > > tpm_crb: Implement command and response chunking logic > > > > > > tpm: Increase TPM_BUFSIZE to 64kB for chunking support > > 64kb? I am only increasing the TPM buffer to 8kb. More does not seem to be > necessary.
That was a mistake in v1. I have changed that to 8kb in v2. https://lore.kernel.org/all/[email protected]/ > > > > > > > > > > > > > drivers/char/tpm/tpm.h | 2 +- > > > > > > drivers/char/tpm/tpm_crb.c | 194 > > > > > > ++++++++++++++++++++++++++----------- > > > > > > 2 files changed, 137 insertions(+), 59 deletions(-) > > > > > > > > > > > > -- > > > > > > 2.53.0 > > > > > > > > > > > > > > > > When QEMU has the feature available? > > > > > > > > The QEMU patches are in review at the moment, > > > > here is the link: > > > > https://lore.kernel.org/qemu-devel/[email protected]/ > > > > Hoping to have them merged soon. > > > > > > Right, and additional question: what about swtpm? > > I am waiting for https://github.com/trustedComputingGroup/tpm to show rev185 > with PQC support so that I can merge my patches based on 'their' PQC support > into the public libtpms repo. > Regards, Arun Menon
