On Tue, May 20, 2025 at 06:06:50PM +0200, Stefano Garzarella wrote:
> On Thu, 15 May 2025 at 03:45, Jarkko Sakkinen <jar...@kernel.org> wrote:
> >
> > On Wed, May 14, 2025 at 03:46:30PM +0200, Stefano Garzarella wrote:
> > > From: Stefano Garzarella <sgarz...@redhat.com>
> > >
> > > This driver does not support interrupts, and receiving the response is
> > > synchronous with sending the command.
> > >
> > > Enable synchronous send() with TPM_CHIP_FLAG_SYNC, which implies that
> > > ->send() already fills the provided buffer with a response, and ->recv()
> > > is not implemented.
> > >
> > > Keep using the same pre-allocated buffer to avoid having to allocate
> > > it for each command. We need the buffer to have the header required by
> > > the SVSM protocol and the command contiguous in memory.
> > >
> > > Signed-off-by: Stefano Garzarella <sgarz...@redhat.com>
> > > ---
> > > v5:
> > > - changed order and parameter names to match tpm_try_transmit() [Jarkko]
> > > v4:
> > > - reworked commit description [Jarkko]
> > > ---
> > > drivers/char/tpm/tpm_svsm.c | 27 +++++++++++----------------
> > > 1 file changed, 11 insertions(+), 16 deletions(-)
> > >
> > > diff --git a/drivers/char/tpm/tpm_svsm.c b/drivers/char/tpm/tpm_svsm.c
> > > index 0847cbf450b4..f5ba0f64850b 100644
> > > --- a/drivers/char/tpm/tpm_svsm.c
> > > +++ b/drivers/char/tpm/tpm_svsm.c
> > > @@ -26,37 +26,31 @@ struct tpm_svsm_priv {
> > > };
> > >
> > > static int tpm_svsm_send(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
> > > - size_t len)
> > > + size_t cmd_len)
> > > {
> > > struct tpm_svsm_priv *priv = dev_get_drvdata(&chip->dev);
> > > int ret;
> > >
> > > - ret = svsm_vtpm_cmd_request_fill(priv->buffer, 0, buf, len);
> > > + ret = svsm_vtpm_cmd_request_fill(priv->buffer, 0, buf, cmd_len);
> > > if (ret)
> > > return ret;
> > >
> > > /*
> > > * The SVSM call uses the same buffer for the command and for the
> > > - * response, so after this call, the buffer will contain the
> > > response
> > > - * that can be used by .recv() op.
> > > + * response, so after this call, the buffer will contain the
> > > response.
> > > + *
> > > + * Note: we have to use an internal buffer because the device in
> > > SVSM
> > > + * expects the svsm_vtpm header + data to be physically contiguous.
> > > */
> > > - return snp_svsm_vtpm_send_command(priv->buffer);
> > > -}
> > > -
> > > -static int tpm_svsm_recv(struct tpm_chip *chip, u8 *buf, size_t len)
> > > -{
> > > - struct tpm_svsm_priv *priv = dev_get_drvdata(&chip->dev);
> > > + ret = snp_svsm_vtpm_send_command(priv->buffer);
> > > + if (ret)
> > > + return ret;
> > >
> > > - /*
> > > - * The internal buffer contains the response after we send the
> > > command
> > > - * to SVSM.
> > > - */
> > > - return svsm_vtpm_cmd_response_parse(priv->buffer, buf, len);
> > > + return svsm_vtpm_cmd_response_parse(priv->buffer, buf, bufsiz);
> > > }
> > >
> > > static struct tpm_class_ops tpm_chip_ops = {
> > > .flags = TPM_OPS_AUTO_STARTUP,
> > > - .recv = tpm_svsm_recv,
> > > .send = tpm_svsm_send,
> > > };
> > >
> > > @@ -85,6 +79,7 @@ static int __init tpm_svsm_probe(struct platform_device
> > > *pdev)
> > >
> > > dev_set_drvdata(&chip->dev, priv);
> > >
> > > + chip->flags |= TPM_CHIP_FLAG_SYNC;
> > > err = tpm2_probe(chip);
> > > if (err)
> > > return err;
> > > --
> > > 2.49.0
> > >
> > >
> >
> > I can pick this for 6.16.
>
> Great, thanks!
Can you rebase this on top of my next branch and send one more version
of the series (fake ancestor crap)?
>
> Stefano
>
BR, Jarkko
