| Message ID | 20250408083208.43512-3-sgarzare@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | tpm: add support for sync send() and use it in ftpm and svsm drivers | expand |
On Tue, Apr 08, 2025 at 10:32:06AM +0200, Stefano Garzarella wrote: > From: Stefano Garzarella <sgarzare@redhat.com> > > Some devices do not support interrupts and provide a single synchronous > operation to send the command and receive the response on the same buffer. > > Currently, these types of drivers must use an internal buffer where they > temporarily store the response between .send() and recv() calls. > > Introduce a new flag (TPM_CHIP_FLAG_SYNC) to support synchronous send(). > If that flag is set by the driver, tpm_try_transmit() will use the send() > callback to send the command and receive the response on the same buffer > synchronously. In that case send() return the number of bytes of the > response on success, or -errno on failure. > > Suggested-by: Jason Gunthorpe <jgg@ziepe.ca> > Suggested-by: Jarkko Sakkinen <jarkko@kernel.org> > Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> > --- > include/linux/tpm.h | 1 + > drivers/char/tpm/tpm-interface.c | 18 +++++++++++++++--- > 2 files changed, 16 insertions(+), 3 deletions(-) > > diff --git a/include/linux/tpm.h b/include/linux/tpm.h > index 2e38edd5838c..0e9746dc9d30 100644 > --- a/include/linux/tpm.h > +++ b/include/linux/tpm.h > @@ -350,6 +350,7 @@ enum tpm_chip_flags { > TPM_CHIP_FLAG_SUSPENDED = BIT(8), > TPM_CHIP_FLAG_HWRNG_DISABLED = BIT(9), > TPM_CHIP_FLAG_DISABLE = BIT(10), > + TPM_CHIP_FLAG_SYNC = BIT(11), > }; > > #define to_tpm_chip(d) container_of(d, struct tpm_chip, dev) > diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c > index 3b6ddcdb4051..9fbe84b5a131 100644 > --- a/drivers/char/tpm/tpm-interface.c > +++ b/drivers/char/tpm/tpm-interface.c > @@ -114,8 +114,17 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip, void *buf, size_t bufsiz) > return rc; > } > > - /* A sanity check. send() should just return zero on success e.g. > - * not the command length. > + /* Synchronous devices return the response directly during the send() > + * call in the same buffer. > + */ Nit: /* * ... It's wrong in the existing comment. > + if (chip->flags & TPM_CHIP_FLAG_SYNC) { > + len = rc; > + rc = 0; > + goto out_send_sync; > + } > + > + /* A sanity check. send() of asynchronous devices should just return > + * zero on success e.g. not the command length. > */ > if (rc > 0) { > dev_warn(&chip->dev, > @@ -151,7 +160,10 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip, void *buf, size_t bufsiz) > if (len < 0) { > rc = len; > dev_err(&chip->dev, "tpm_transmit: tpm_recv: error %d\n", rc); > - } else if (len < TPM_HEADER_SIZE || len != be32_to_cpu(header->length)) > + return rc; > + } > +out_send_sync: out_sync would be sufficient > + if (len < TPM_HEADER_SIZE || len != be32_to_cpu(header->length)) > rc = -EFAULT; > > return rc ? rc : len; > -- > 2.49.0 > BR, Jarkko
On Tue, Apr 08, 2025 at 06:31:30PM +0300, Jarkko Sakkinen wrote: >On Tue, Apr 08, 2025 at 10:32:06AM +0200, Stefano Garzarella wrote: >> From: Stefano Garzarella <sgarzare@redhat.com> >> >> Some devices do not support interrupts and provide a single synchronous >> operation to send the command and receive the response on the same buffer. >> >> Currently, these types of drivers must use an internal buffer where they >> temporarily store the response between .send() and recv() calls. >> >> Introduce a new flag (TPM_CHIP_FLAG_SYNC) to support synchronous send(). >> If that flag is set by the driver, tpm_try_transmit() will use the send() >> callback to send the command and receive the response on the same buffer >> synchronously. In that case send() return the number of bytes of the >> response on success, or -errno on failure. >> >> Suggested-by: Jason Gunthorpe <jgg@ziepe.ca> >> Suggested-by: Jarkko Sakkinen <jarkko@kernel.org> >> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> >> --- >> include/linux/tpm.h | 1 + >> drivers/char/tpm/tpm-interface.c | 18 +++++++++++++++--- >> 2 files changed, 16 insertions(+), 3 deletions(-) >> >> diff --git a/include/linux/tpm.h b/include/linux/tpm.h >> index 2e38edd5838c..0e9746dc9d30 100644 >> --- a/include/linux/tpm.h >> +++ b/include/linux/tpm.h >> @@ -350,6 +350,7 @@ enum tpm_chip_flags { >> TPM_CHIP_FLAG_SUSPENDED = BIT(8), >> TPM_CHIP_FLAG_HWRNG_DISABLED = BIT(9), >> TPM_CHIP_FLAG_DISABLE = BIT(10), >> + TPM_CHIP_FLAG_SYNC = BIT(11), >> }; >> >> #define to_tpm_chip(d) container_of(d, struct tpm_chip, dev) >> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c >> index 3b6ddcdb4051..9fbe84b5a131 100644 >> --- a/drivers/char/tpm/tpm-interface.c >> +++ b/drivers/char/tpm/tpm-interface.c >> @@ -114,8 +114,17 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip, void *buf, size_t bufsiz) >> return rc; >> } >> >> - /* A sanity check. send() should just return zero on success e.g. >> - * not the command length. >> + /* Synchronous devices return the response directly during the send() >> + * call in the same buffer. >> + */ > >Nit: > >/* > * ... > >It's wrong in the existing comment. Yep, I'll fix. > >> + if (chip->flags & TPM_CHIP_FLAG_SYNC) { >> + len = rc; >> + rc = 0; >> + goto out_send_sync; >> + } >> + >> + /* A sanity check. send() of asynchronous devices should just return And I'll fix also this of course. >> + * zero on success e.g. not the command length. >> */ >> if (rc > 0) { >> dev_warn(&chip->dev, >> @@ -151,7 +160,10 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip, void *buf, size_t bufsiz) >> if (len < 0) { >> rc = len; >> dev_err(&chip->dev, "tpm_transmit: tpm_recv: error %d\n", rc); >> - } else if (len < TPM_HEADER_SIZE || len != be32_to_cpu(header->length)) >> + return rc; >> + } >> +out_send_sync: > >out_sync would be sufficient sure, I'll fix in v3. Thanks, Stefano
diff --git a/include/linux/tpm.h b/include/linux/tpm.h index 2e38edd5838c..0e9746dc9d30 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -350,6 +350,7 @@ enum tpm_chip_flags { TPM_CHIP_FLAG_SUSPENDED = BIT(8), TPM_CHIP_FLAG_HWRNG_DISABLED = BIT(9), TPM_CHIP_FLAG_DISABLE = BIT(10), + TPM_CHIP_FLAG_SYNC = BIT(11), }; #define to_tpm_chip(d) container_of(d, struct tpm_chip, dev) diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c index 3b6ddcdb4051..9fbe84b5a131 100644 --- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -114,8 +114,17 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip, void *buf, size_t bufsiz) return rc; } - /* A sanity check. send() should just return zero on success e.g. - * not the command length. + /* Synchronous devices return the response directly during the send() + * call in the same buffer. + */ + if (chip->flags & TPM_CHIP_FLAG_SYNC) { + len = rc; + rc = 0; + goto out_send_sync; + } + + /* A sanity check. send() of asynchronous devices should just return + * zero on success e.g. not the command length. */ if (rc > 0) { dev_warn(&chip->dev, @@ -151,7 +160,10 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip, void *buf, size_t bufsiz) if (len < 0) { rc = len; dev_err(&chip->dev, "tpm_transmit: tpm_recv: error %d\n", rc); - } else if (len < TPM_HEADER_SIZE || len != be32_to_cpu(header->length)) + return rc; + } +out_send_sync: + if (len < TPM_HEADER_SIZE || len != be32_to_cpu(header->length)) rc = -EFAULT; return rc ? rc : len;