On Tue, Aug 03, 2021 at 04:26:22PM -0400, Stefan Berger wrote: > From: Stefan Berger <stefanb@xxxxxxxxxxxxx> > > When rngd is run as root then lots of these types of message will appear > in the kernel log if the TPM has been configured to provide random bytes: > > [ 7406.275163] tpm tpm0: tpm_transmit: tpm_recv: error -4 > > The issue is caused by the following call that is interrupted while > waiting for the TPM's response. > > sig = wait_event_interruptible(ibmvtpm->wq, > !ibmvtpm->tpm_processing_cmd); > > Rather than waiting for the response in the low level driver, have it use > the polling loop in tpm_try_transmit() that uses a command's duration to > poll until a result has been returned by the TPM, thus ending when the > timeout has occurred but not responding to signals and ctrl-c anymore. To > stay in this polling loop extend tpm_ibmvtpm_status() to return > TPM_STATUS_BUSY for as long as the vTPM is busy. Since the loop requires > the TPM's timeouts, get them now using tpm_get_timeouts() after setting > the TPM2 version flag on the chip. > > Rename the tpm_processing_cmd to tpm_status in ibmvtpm_dev and set the > TPM_STATUS_BUSY flag while the vTPM is busy processing a command. > > To recreat the resolved issue start rngd like this: > > sudo rngd -r /dev/hwrng -t > sudo rngd -r /dev/tpm0 -t > > Link: https://bugzilla.redhat.com/show_bug.cgi?id=1981473 > Fixes: 6674ff145eef ("tpm_ibmvtpm: properly handle interrupted packet receptions") > Cc: Nayna Jain <nayna@xxxxxxxxxxxxx> > Cc: George Wilson <gcwilson@xxxxxxxxxxxxx> > Reported-by: Nageswara R Sastry <rnsastry@xxxxxxxxxxxxx> > Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxx> > > --- > > v2: > - reworded commit text > --- > drivers/char/tpm/tpm_ibmvtpm.c | 31 ++++++++++++++++++------------- > drivers/char/tpm/tpm_ibmvtpm.h | 3 ++- > 2 files changed, 20 insertions(+), 14 deletions(-) > > diff --git a/drivers/char/tpm/tpm_ibmvtpm.c b/drivers/char/tpm/tpm_ibmvtpm.c > index 903604769de9..5d795866b483 100644 > --- a/drivers/char/tpm/tpm_ibmvtpm.c > +++ b/drivers/char/tpm/tpm_ibmvtpm.c > @@ -106,17 +106,12 @@ static int tpm_ibmvtpm_recv(struct tpm_chip *chip, u8 *buf, size_t count) > { > struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev); > u16 len; > - int sig; > > if (!ibmvtpm->rtce_buf) { > dev_err(ibmvtpm->dev, "ibmvtpm device is not ready\n"); > return 0; > } > > - sig = wait_event_interruptible(ibmvtpm->wq, !ibmvtpm->tpm_processing_cmd); > - if (sig) > - return -EINTR; > - > len = ibmvtpm->res_len; > > if (count < len) { > @@ -220,11 +215,12 @@ static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count) > return -EIO; > } > > - if (ibmvtpm->tpm_processing_cmd) { > + if ((ibmvtpm->tpm_status & TPM_STATUS_BUSY)) { > dev_info(ibmvtpm->dev, > "Need to wait for TPM to finish\n"); > /* wait for previous command to finish */ > - sig = wait_event_interruptible(ibmvtpm->wq, !ibmvtpm->tpm_processing_cmd); > + sig = wait_event_interruptible(ibmvtpm->wq, > + (ibmvtpm->tpm_status & TPM_STATUS_BUSY) == 0); > if (sig) > return -EINTR; > } > @@ -237,7 +233,7 @@ static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count) > * set the processing flag before the Hcall, since we may get the > * result (interrupt) before even being able to check rc. > */ > - ibmvtpm->tpm_processing_cmd = true; > + ibmvtpm->tpm_status |= TPM_STATUS_BUSY; > > again: > rc = ibmvtpm_send_crq(ibmvtpm->vdev, > @@ -255,7 +251,7 @@ static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count) > goto again; > } > dev_err(ibmvtpm->dev, "tpm_ibmvtpm_send failed rc=%d\n", rc); > - ibmvtpm->tpm_processing_cmd = false; > + ibmvtpm->tpm_status &= ~TPM_STATUS_BUSY; > } > > spin_unlock(&ibmvtpm->rtce_lock); > @@ -269,7 +265,9 @@ static void tpm_ibmvtpm_cancel(struct tpm_chip *chip) > > static u8 tpm_ibmvtpm_status(struct tpm_chip *chip) > { > - return 0; > + struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev); > + > + return ibmvtpm->tpm_status; > } > > /** > @@ -457,7 +455,7 @@ static const struct tpm_class_ops tpm_ibmvtpm = { > .send = tpm_ibmvtpm_send, > .cancel = tpm_ibmvtpm_cancel, > .status = tpm_ibmvtpm_status, > - .req_complete_mask = 0, > + .req_complete_mask = TPM_STATUS_BUSY, > .req_complete_val = 0, > .req_canceled = tpm_ibmvtpm_req_canceled, > }; > @@ -550,7 +548,7 @@ static void ibmvtpm_crq_process(struct ibmvtpm_crq *crq, > case VTPM_TPM_COMMAND_RES: > /* len of the data in rtce buffer */ > ibmvtpm->res_len = be16_to_cpu(crq->len); > - ibmvtpm->tpm_processing_cmd = false; > + ibmvtpm->tpm_status &= ~TPM_STATUS_BUSY; > wake_up_interruptible(&ibmvtpm->wq); > return; > default: > @@ -688,8 +686,15 @@ static int tpm_ibmvtpm_probe(struct vio_dev *vio_dev, > goto init_irq_cleanup; > } > > - if (!strcmp(id->compat, "IBM,vtpm20")) { > + > + if (!strcmp(id->compat, "IBM,vtpm20")) > chip->flags |= TPM_CHIP_FLAG_TPM2; > + > + rc = tpm_get_timeouts(chip); > + if (rc) > + goto init_irq_cleanup; > + > + if (chip->flags & TPM_CHIP_FLAG_TPM2) { > rc = tpm2_get_cc_attrs_tbl(chip); > if (rc) > goto init_irq_cleanup; > diff --git a/drivers/char/tpm/tpm_ibmvtpm.h b/drivers/char/tpm/tpm_ibmvtpm.h > index b92aa7d3e93e..252f1cccdfc5 100644 > --- a/drivers/char/tpm/tpm_ibmvtpm.h > +++ b/drivers/char/tpm/tpm_ibmvtpm.h > @@ -41,7 +41,8 @@ struct ibmvtpm_dev { > wait_queue_head_t wq; > u16 res_len; > u32 vtpm_version; > - bool tpm_processing_cmd; > + u8 tpm_status; > +#define TPM_STATUS_BUSY (1 << 0) /* vtpm is processing a command */ > }; > > #define CRQ_RES_BUF_SIZE PAGE_SIZE > -- > 2.31.1 > > Please do not do the rename in the bug fix. If you really want to rename, then this must be split into two commits. /Jarkko
