| Message ID | 20210209221339.875739-1-stefanb@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | tpm: ibmvtpm: Avoid -EINTR error when IMA talks to TPM | expand |
On Tue, Feb 09, 2021 at 05:13:39PM -0500, Stefan Berger wrote: > When IMA is taking measurements during compilation for example and a > user presses ctrl-c to abort the compilation, lots of these types of > messages will appear in the kernel log: > > [ 7406.275163] tpm tpm0: tpm_transmit: tpm_recv: error -4 > [ 7406.275242] ima: Error Communicating to TPM chip, result: -4 > > The issue is caused by the fact that the IBM vTPM driver's recv() > function is called immediately after send() without waiting for > status on whether a response was received. It currently waits for > the current command to finish using this call that ends up throwing > these error messages because it is 'interruptible': Why it is an issue? > sig = wait_event_interruptible(ibmvtpm->wq, > !ibmvtpm->tpm_processing_cmd); > > Instead, it should be using 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 users' ctrl-c request anymore. To stay in this > polling loop we now extend tpm_ibmvtpm_status() to return > PM_STATUS_BUSY for as long as the vTPM is busy. Since we will need > the timeouts in this loop now we get the TPM 1.2 and TPM 2 timeouts > with tpm_get_timeouts(). > > We change tpm_processing_cmd to tpm_status and set the TPM_STATUS_BUSY > flag while the vTPM is busy processing a command. Please, never use "we". The commit message should describe in imperative form the action taken. > > Signed-off-by: Stefan Berger <stefanb@linux.ibm.com> > Fixes: 18b3670d79ae9 ("tpm: ibmvtpm: Add support for TPM2") > Cc: Nayna Jain <nayna@linux.ibm.com> > Cc: George Wilson <gcwilson@linux.ibm.com> Your SOB should be last. > --- > 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 994385bf37c0..6290bd8889e4 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; > } > > /** > @@ -459,7 +457,7 @@ 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, > }; > @@ -552,7 +550,7 @@ 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: > @@ -690,8 +688,15 @@ 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 > -- > 2.29.2 > >
On 2/12/21 4:05 AM, Jarkko Sakkinen wrote: > On Tue, Feb 09, 2021 at 05:13:39PM -0500, Stefan Berger wrote: >> When IMA is taking measurements during compilation for example and a >> user presses ctrl-c to abort the compilation, lots of these types of >> messages will appear in the kernel log: >> >> [ 7406.275163] tpm tpm0: tpm_transmit: tpm_recv: error -4 >> [ 7406.275242] ima: Error Communicating to TPM chip, result: -4 >> >> The issue is caused by the fact that the IBM vTPM driver's recv() >> function is called immediately after send() without waiting for >> status on whether a response was received. It currently waits for >> the current command to finish using this call that ends up throwing >> these error messages because it is 'interruptible': > Why it is an issue? The issue is the many kernel log entries we get when someone interrupts an application with ctrl-c while IMA is taking measurements of files it reads.I thought that was clear from the first paragraph.
diff --git a/drivers/char/tpm/tpm_ibmvtpm.c b/drivers/char/tpm/tpm_ibmvtpm.c index 994385bf37c0..6290bd8889e4 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; } /** @@ -459,7 +457,7 @@ 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, }; @@ -552,7 +550,7 @@ 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: @@ -690,8 +688,15 @@ 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
When IMA is taking measurements during compilation for example and a user presses ctrl-c to abort the compilation, lots of these types of messages will appear in the kernel log: [ 7406.275163] tpm tpm0: tpm_transmit: tpm_recv: error -4 [ 7406.275242] ima: Error Communicating to TPM chip, result: -4 The issue is caused by the fact that the IBM vTPM driver's recv() function is called immediately after send() without waiting for status on whether a response was received. It currently waits for the current command to finish using this call that ends up throwing these error messages because it is 'interruptible': sig = wait_event_interruptible(ibmvtpm->wq, !ibmvtpm->tpm_processing_cmd); Instead, it should be using 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 users' ctrl-c request anymore. To stay in this polling loop we now extend tpm_ibmvtpm_status() to return PM_STATUS_BUSY for as long as the vTPM is busy. Since we will need the timeouts in this loop now we get the TPM 1.2 and TPM 2 timeouts with tpm_get_timeouts(). We change tpm_processing_cmd to tpm_status and set the TPM_STATUS_BUSY flag while the vTPM is busy processing a command. Signed-off-by: Stefan Berger <stefanb@linux.ibm.com> Fixes: 18b3670d79ae9 ("tpm: ibmvtpm: Add support for TPM2") Cc: Nayna Jain <nayna@linux.ibm.com> Cc: George Wilson <gcwilson@linux.ibm.com> --- drivers/char/tpm/tpm_ibmvtpm.c | 31 ++++++++++++++++++------------- drivers/char/tpm/tpm_ibmvtpm.h | 3 ++- 2 files changed, 20 insertions(+), 14 deletions(-)