tpm_spapr: Support suspend and resume

Extend the tpm_spapr frontend with VM suspend and resume support.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Message-Id: <20200121152935.649898-5-stefanb@linux.ibm.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

hw/tpm/tpm_spapr.c

@@ -76,6 +76,8 @@ typedef struct {
 
     unsigned char *buffer;
 
+    uint32_t numbytes; /* number of bytes to deliver on resume */
+
     TPMBackendCmd cmd;
 
     TPMBackend *be_driver;
@@ -240,6 +242,14 @@ static void tpm_spapr_request_completed(TPMIf *ti, int ret)
 
     /* a max. of be_buffer_size bytes can be transported */
     len = MIN(tpm_cmd_get_size(s->buffer), s->be_buffer_size);
+
+    if (runstate_check(RUN_STATE_FINISH_MIGRATE)) {
+        trace_tpm_spapr_caught_response(len);
+        /* defer delivery of response until .post_load */
+        s->numbytes = len;
+        return;
+    }
+
     rc = spapr_vio_dma_write(&s->vdev, be32_to_cpu(crq->data),
                              s->buffer, len);
 
@@ -288,6 +298,7 @@ static void tpm_spapr_reset(SpaprVioDevice *dev)
     SpaprTpmState *s = VIO_SPAPR_VTPM(dev);
 
     s->state = SPAPR_VTPM_STATE_NONE;
+    s->numbytes = 0;
 
     s->be_tpm_version = tpm_backend_get_tpm_version(s->be_driver);
 
@@ -309,9 +320,48 @@ static enum TPMVersion tpm_spapr_get_version(TPMIf *ti)
     return tpm_backend_get_tpm_version(s->be_driver);
 }
 
+/* persistent state handling */
+
+static int tpm_spapr_pre_save(void *opaque)
+{
+    SpaprTpmState *s = opaque;
+
+    tpm_backend_finish_sync(s->be_driver);
+    /*
+     * we cannot deliver the results to the VM since DMA would touch VM memory
+     */
+
+    return 0;
+}
+
+static int tpm_spapr_post_load(void *opaque, int version_id)
+{
+    SpaprTpmState *s = opaque;
+
+    if (s->numbytes) {
+        trace_tpm_spapr_post_load();
+        /* deliver the results to the VM via DMA */
+        tpm_spapr_request_completed(TPM_IF(s), 0);
+        s->numbytes = 0;
+    }
+
+    return 0;
+}
+
 static const VMStateDescription vmstate_spapr_vtpm = {
     .name = "tpm-spapr",
-    .unmigratable = 1,
+    .pre_save = tpm_spapr_pre_save,
+    .post_load = tpm_spapr_post_load,
+    .fields = (VMStateField[]) {
+        VMSTATE_SPAPR_VIO(vdev, SpaprTpmState),
+
+        VMSTATE_UINT8(state, SpaprTpmState),
+        VMSTATE_UINT32(numbytes, SpaprTpmState),
+        VMSTATE_VBUFFER_UINT32(buffer, SpaprTpmState, 0, NULL, numbytes),
+        /* remember DMA address */
+        VMSTATE_UINT32(crq.data, SpaprTpmState),
+        VMSTATE_END_OF_LIST(),
+    }
 };
 
 static Property tpm_spapr_properties[] = {

hw/tpm/trace-events

@@ -67,3 +67,5 @@ tpm_spapr_do_crq_get_version(uint32_t version) "response: version %u"
 tpm_spapr_do_crq_prepare_to_suspend(void) "response: preparing to suspend"
 tpm_spapr_do_crq_unknown_msg_type(uint8_t type) "Unknown message type 0x%02x"
 tpm_spapr_do_crq_unknown_crq(uint8_t raw1, uint8_t raw2) "unknown CRQ 0x%02x 0x%02x ..."
+tpm_spapr_post_load(void) "Delivering TPM response after resume"
+tpm_spapr_caught_response(uint32_t v) "Caught response to deliver after resume: %u bytes"