[Xen-devel] [PATCH 2/4] stubdom/vtpm: Add reconfiguration support

[Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>]

Allow the vtpm device to be disconnected and reconnected so that a
bootloader (like pv-grub) can submit measurements and return the vtpm
device to its initial state before booting the target kernel.

Signed-off-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
---
 extras/mini-os/include/tpmfront.h |  2 +-
 extras/mini-os/lib/sys.c          |  2 +-
 extras/mini-os/tpmback.c          |  5 +++++
 extras/mini-os/tpmfront.c         | 15 +++++++++------
 stubdom/vtpm/vtpm.c               |  2 +-
 5 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/extras/mini-os/include/tpmfront.h 
b/extras/mini-os/include/tpmfront.h
index a0c7c4d..913faa4 100644
--- a/extras/mini-os/include/tpmfront.h
+++ b/extras/mini-os/include/tpmfront.h
@@ -61,7 +61,7 @@ struct tpmfront_dev {
 /*Initialize frontend */
 struct tpmfront_dev* init_tpmfront(const char* nodename);
 /*Shutdown frontend */
-void shutdown_tpmfront(struct tpmfront_dev* dev);
+void shutdown_tpmfront(struct tpmfront_dev* dev, int for_reconfig);
 
 /* Send a tpm command to the backend and wait for the response
  *
diff --git a/extras/mini-os/lib/sys.c b/extras/mini-os/lib/sys.c
index 3cc3340..03da4f0 100644
--- a/extras/mini-os/lib/sys.c
+++ b/extras/mini-os/lib/sys.c
@@ -459,7 +459,7 @@ int close(int fd)
 #endif
 #ifdef CONFIG_TPMFRONT
        case FTYPE_TPMFRONT:
-            shutdown_tpmfront(files[fd].tpmfront.dev);
+            shutdown_tpmfront(files[fd].tpmfront.dev, 0);
            files[fd].type = FTYPE_NONE;
            return 0;
 #endif
diff --git a/extras/mini-os/tpmback.c b/extras/mini-os/tpmback.c
index 2d31061..ea42235 100644
--- a/extras/mini-os/tpmback.c
+++ b/extras/mini-os/tpmback.c
@@ -664,6 +664,7 @@ static int frontend_changed(tpmif_t* tpmif)
    switch (state) {
       case XenbusStateInitialising:
       case XenbusStateInitialised:
+      case XenbusStateReconfigured:
         break;
 
       case XenbusStateConnected:
@@ -678,6 +679,10 @@ static int frontend_changed(tpmif_t* tpmif)
         tpmif_change_state(tpmif, XenbusStateClosing);
         break;
 
+      case XenbusStateReconfiguring:
+         disconnect_fe(tpmif);
+        break;
+
       case XenbusStateUnknown: /* keep it here */
       case XenbusStateClosed:
         free_tpmif(tpmif);
diff --git a/extras/mini-os/tpmfront.c b/extras/mini-os/tpmfront.c
index c1cbab3..b725ba0 100644
--- a/extras/mini-os/tpmfront.c
+++ b/extras/mini-os/tpmfront.c
@@ -344,10 +344,10 @@ struct tpmfront_dev* init_tpmfront(const char* _nodename)
    return dev;
 
 error:
-   shutdown_tpmfront(dev);
+   shutdown_tpmfront(dev, 0);
    return NULL;
 }
-void shutdown_tpmfront(struct tpmfront_dev* dev)
+void shutdown_tpmfront(struct tpmfront_dev* dev, int for_reconfig)
 {
    char* err;
    char path[512];
@@ -357,8 +357,7 @@ void shutdown_tpmfront(struct tpmfront_dev* dev)
    TPMFRONT_LOG("Shutting down tpmfront%s\n", for_reconfig ? " for 
reconfigure" : "");
    /* disconnect */
    if(dev->state == XenbusStateConnected) {
-      dev->state = XenbusStateClosing;
-      //FIXME: Transaction for this?
+      dev->state = for_reconfig ? XenbusStateReconfiguring : 
XenbusStateClosing;
       /* Tell backend we are closing */
       if((err = xenbus_printf(XBT_NIL, dev->nodename, "state", "%u", (unsigned 
int) dev->state))) {
         free(err);
@@ -374,15 +373,19 @@ void shutdown_tpmfront(struct tpmfront_dev* dev)
         free(err);
       }
 
+      if (for_reconfig)
+         wait_for_backend_state_changed(dev, XenbusStateReconfigured);
+
       /* Tell backend we are closed */
-      dev->state = XenbusStateClosed;
+      dev->state = for_reconfig ? XenbusStateInitialising : XenbusStateClosed;
       if((err = xenbus_printf(XBT_NIL, dev->nodename, "state", "%u", (unsigned 
int) dev->state))) {
         TPMFRONT_ERR("Unable to write to %s, error was %s", dev->nodename, 
err);
         free(err);
       }
 
       /* Wait for the backend to close and unmap shared pages, ignore any 
errors */
-      wait_for_backend_state_changed(dev, XenbusStateClosed);
+      if (!for_reconfig)
+         wait_for_backend_state_changed(dev, XenbusStateClosed);
 
       /* Close event channel and unmap shared page */
       mask_evtchn(dev->evtchn);
diff --git a/stubdom/vtpm/vtpm.c b/stubdom/vtpm/vtpm.c
index 71aef78..c33e078 100644
--- a/stubdom/vtpm/vtpm.c
+++ b/stubdom/vtpm/vtpm.c
@@ -394,7 +394,7 @@ abort_postvtpmblk:
 abort_postrng:
 
    /* Close devices */
-   shutdown_tpmfront(tpmfront_dev);
+   shutdown_tpmfront(tpmfront_dev, 0);
 abort_posttpmfront:
    shutdown_tpmback();
 
-- 
1.7.11.7


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