tpm: ibmvtpm: Wait for buffer to be set before proceeding

[ Upstream commit d8d74ea3c00214aee1e1826ca18e77944812b9b4 ]

Synchronize with the results from the CRQs before continuing with
the initialization. This avoids trying to send TPM commands while
the rtce buffer has not been allocated, yet.

This patch fixes an existing race condition that may occurr if the
hypervisor does not quickly respond to the VTPM_GET_RTCE_BUFFER_SIZE
request sent during initialization and therefore the ibmvtpm->rtce_buf
has not been allocated at the time the first TPM command is sent.

Fixes: 132f76294744 ("drivers/char/tpm: Add new device driver to support IBM vTPM")
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Acked-by: Nayna Jain <nayna@linux.ibm.com>
Tested-by: Nayna Jain <nayna@linux.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/char/tpm/tpm_ibmvtpm.c b/drivers/char/tpm/tpm_ibmvtpm.c
index 569e93e1f06ccdc978d30ee6035aa850dc2f5e72..3ba67bc6baba01c545e13ad518ea5e58846213b3 100644 (file)
--- a/drivers/char/tpm/tpm_ibmvtpm.c
+++ b/drivers/char/tpm/tpm_ibmvtpm.c
@@ -588,6 +588,7 @@ static irqreturn_t ibmvtpm_interrupt(int irq, void *vtpm_instance)
         */
        while ((crq = ibmvtpm_crq_get_next(ibmvtpm)) != NULL) {
                ibmvtpm_crq_process(crq, ibmvtpm);
+               wake_up_interruptible(&ibmvtpm->crq_queue.wq);
                crq->valid = 0;
                smp_wmb();
        }
@@ -635,6 +636,7 @@ static int tpm_ibmvtpm_probe(struct vio_dev *vio_dev,
        }
 
        crq_q->num_entry = CRQ_RES_BUF_SIZE / sizeof(*crq_q->crq_addr);
+       init_waitqueue_head(&crq_q->wq);
        ibmvtpm->crq_dma_handle = dma_map_single(dev, crq_q->crq_addr,
                                                 CRQ_RES_BUF_SIZE,
                                                 DMA_BIDIRECTIONAL);
@@ -687,6 +689,13 @@ static int tpm_ibmvtpm_probe(struct vio_dev *vio_dev,
        if (rc)
                goto init_irq_cleanup;
 
+       if (!wait_event_timeout(ibmvtpm->crq_queue.wq,
+                               ibmvtpm->rtce_buf != NULL,
+                               HZ)) {
+               dev_err(dev, "CRQ response timed out\n");
+               goto init_irq_cleanup;
+       }
+
        return tpm_chip_register(chip);
 init_irq_cleanup:
        do {

diff --git a/drivers/char/tpm/tpm_ibmvtpm.h b/drivers/char/tpm/tpm_ibmvtpm.h
index 91dfe766d08007e9dfa5fa91e7d5a132a8b85830..4f6a124601db414dcbbf5a32fb83569db4a34ffe 100644 (file)
--- a/drivers/char/tpm/tpm_ibmvtpm.h
+++ b/drivers/char/tpm/tpm_ibmvtpm.h
@@ -31,6 +31,7 @@ struct ibmvtpm_crq_queue {
        struct ibmvtpm_crq *crq_addr;
        u32 index;
        u32 num_entry;
+       wait_queue_head_t wq;
 };
 
 struct ibmvtpm_dev {