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[Xen-devel] [v3 3/5] Qemu-Xen-vTPM: Register Xen stubdom vTPM frontend driver



This drvier transfers any request/repond between TPM xenstubdoms
driver and Xen vTPM stubdom, and facilitates communications between
Xen vTPM stubdom domain and vTPM xenstubdoms driver. It is a glue for
the TPM xenstubdoms driver and Xen stubdom vTPM domain that provides
the actual TPM functionality.

(Xen) Xen backend driver should run before running this frontend, and
initialize XenStore as the following for communication.

[XenStore]
 ..
  FE.DOMAIN.ID
   device = ""
    vtpm = ""
     0 = ""
      backend = "/local/domain/{BE.DOMAIN.ID}/backend/vtpm/{FE.DOMAIN.ID}/0"
      backend-id = "BE.DOMAIN.ID"
      state = "1"
      handle = "0"
 ..

(QEMU) xen_vtpmdev_ops is initialized with the following process:
  xen_hvm_init()
    [...]
    -->xen_fe_register("vtpm", ...)
      -->xenstore_fe_scan()
        -->xen_fe_get_xendev()
          --> XenDevOps.alloc()
        -->xen_fe_check()
          --> XenDevOps.init()
          --> XenDevOps.initialise()
          --> XenDevOps.connected()
        -->xs_watch()
    [...]

--Changes in v3:
-Move xen_stubdom_vtpm.c to xen_vtpm_frontend.c
-Read Xen vTPM status via XenStore

Signed-off-by: Quan Xu <quan.xu@xxxxxxxxx>
---
 hw/tpm/Makefile.objs         |   1 +
 hw/tpm/xen_vtpm_frontend.c   | 264 +++++++++++++++++++++++++++++++++++++++++++
 hw/xen/xen_backend.c         |  34 ++++++
 include/hw/xen/xen_backend.h |   9 +-
 include/hw/xen/xen_common.h  |   6 +
 xen-hvm.c                    |  16 +++
 6 files changed, 328 insertions(+), 2 deletions(-)
 create mode 100644 hw/tpm/xen_vtpm_frontend.c

diff --git a/hw/tpm/Makefile.objs b/hw/tpm/Makefile.objs
index 99f5983..57919fa 100644
--- a/hw/tpm/Makefile.objs
+++ b/hw/tpm/Makefile.objs
@@ -1,2 +1,3 @@
 common-obj-$(CONFIG_TPM_TIS) += tpm_tis.o
 common-obj-$(CONFIG_TPM_PASSTHROUGH) += tpm_passthrough.o
+common-obj-$(CONFIG_TPM_XENSTUBDOMS) += xen_vtpm_frontend.o
diff --git a/hw/tpm/xen_vtpm_frontend.c b/hw/tpm/xen_vtpm_frontend.c
new file mode 100644
index 0000000..00cc888
--- /dev/null
+++ b/hw/tpm/xen_vtpm_frontend.c
@@ -0,0 +1,264 @@
+/*
+ * Connect to Xen vTPM stubdom domain
+ *
+ *  Copyright (c) 2014 Intel Corporation
+ *  Authors:
+ *    Quan Xu <quan.xu@xxxxxxxxx>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
+#include <signal.h>
+#include <inttypes.h>
+#include <time.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <sys/uio.h>
+
+#include "hw/hw.h"
+#include "block/aio.h"
+#include "hw/xen/xen_backend.h"
+
+enum tpmif_state {
+    TPMIF_STATE_IDLE,        /* no contents / vTPM idle / cancel complete */
+    TPMIF_STATE_SUBMIT,      /* request ready / vTPM working */
+    TPMIF_STATE_FINISH,      /* response ready / vTPM idle */
+    TPMIF_STATE_CANCEL,      /* cancel requested / vTPM working */
+};
+
+static AioContext *vtpm_aio_ctx;
+
+enum status_bits {
+    VTPM_STATUS_RUNNING  = 0x1,
+    VTPM_STATUS_IDLE     = 0x2,
+    VTPM_STATUS_RESULT   = 0x4,
+    VTPM_STATUS_CANCELED = 0x8,
+};
+
+struct tpmif_shared_page {
+    uint32_t length;         /* request/response length in bytes */
+
+    uint8_t  state;           /* enum tpmif_state */
+    uint8_t  locality;        /* for the current request */
+    uint8_t  pad;             /* should be zero */
+
+    uint8_t  nr_extra_pages;  /* extra pages for long packets; may be zero */
+    uint32_t extra_pages[0]; /* grant IDs; length is actually nr_extra_pages */
+};
+
+struct xen_vtpm_dev {
+    struct XenDevice xendev;  /* must be first */
+    struct           tpmif_shared_page *shr;
+    xc_gntshr        *xen_xcs;
+    int              ring_ref;
+    int              bedomid;
+    QEMUBH           *sr_bh;
+};
+
+static uint8_t vtpm_status(struct xen_vtpm_dev *vtpmdev)
+{
+    switch (vtpmdev->shr->state) {
+    case TPMIF_STATE_IDLE:
+    case TPMIF_STATE_FINISH:
+        return VTPM_STATUS_IDLE;
+    case TPMIF_STATE_SUBMIT:
+    case TPMIF_STATE_CANCEL:
+        return VTPM_STATUS_RUNNING;
+    default:
+        return 0;
+    }
+}
+
+static bool vtpm_aio_wait(AioContext *ctx)
+{
+    return aio_poll(ctx, true);
+}
+
+static void sr_bh_handler(void *opaque)
+{
+}
+
+int vtpm_recv(struct XenDevice *xendev, uint8_t* buf, size_t *count)
+{
+    struct xen_vtpm_dev *vtpmdev = container_of(xendev, struct xen_vtpm_dev,
+                                                xendev);
+    struct tpmif_shared_page *shr = vtpmdev->shr;
+    unsigned int offset;
+
+    if (shr->state == TPMIF_STATE_IDLE) {
+        return -ECANCELED;
+    }
+
+    while (vtpm_status(vtpmdev) != VTPM_STATUS_IDLE) {
+        vtpm_aio_wait(vtpm_aio_ctx);
+    }
+
+    offset = sizeof(*shr) + 4*shr->nr_extra_pages;
+    memcpy(buf, offset + (uint8_t *)shr, shr->length);
+    *count = shr->length;
+
+    return 0;
+}
+
+int vtpm_send(struct XenDevice *xendev, uint8_t* buf, size_t count)
+{
+    struct xen_vtpm_dev *vtpmdev = container_of(xendev, struct xen_vtpm_dev,
+                                                xendev);
+    struct tpmif_shared_page *shr = vtpmdev->shr;
+    unsigned int offset = sizeof(*shr) + 4*shr->nr_extra_pages;
+
+    while (vtpm_status(vtpmdev) != VTPM_STATUS_IDLE) {
+        vtpm_aio_wait(vtpm_aio_ctx);
+    }
+
+    memcpy(offset + (uint8_t *)shr, buf, count);
+    shr->length = count;
+    barrier();
+    shr->state = TPMIF_STATE_SUBMIT;
+    xen_wmb();
+    xen_be_send_notify(&vtpmdev->xendev);
+
+    while (vtpm_status(vtpmdev) != VTPM_STATUS_IDLE) {
+        vtpm_aio_wait(vtpm_aio_ctx);
+    }
+
+    return count;
+}
+
+static int vtpm_initialise(struct XenDevice *xendev)
+{
+    struct xen_vtpm_dev *vtpmdev = container_of(xendev, struct xen_vtpm_dev,
+                                                xendev);
+    xs_transaction_t xbt = XBT_NULL;
+    unsigned int ring_ref;
+
+    vtpmdev->xendev.fe = xenstore_read_be_str(&vtpmdev->xendev, "frontend");
+    if (vtpmdev->xendev.fe == NULL) {
+        return -1;
+    }
+
+    /* Get backend domid */
+    if (xenstore_read_fe_int(&vtpmdev->xendev, "backend-id",
+                             &vtpmdev->bedomid)) {
+        return -1;
+    }
+
+    /*alloc share page*/
+    vtpmdev->shr = xc_gntshr_share_pages(vtpmdev->xen_xcs, vtpmdev->bedomid, 1,
+                                         &ring_ref, PROT_READ|PROT_WRITE);
+    vtpmdev->ring_ref = ring_ref;
+    if (vtpmdev->shr == NULL) {
+        return -1;
+    }
+
+    /*Create event channel */
+    if (xen_be_alloc_unbound(&vtpmdev->xendev, 0, vtpmdev->bedomid)) {
+        xc_gntshr_munmap(vtpmdev->xen_xcs, vtpmdev->shr, 1);
+        return -1;
+    }
+
+    xc_evtchn_unmask(vtpmdev->xendev.evtchndev,
+                     vtpmdev->xendev.local_port);
+
+again:
+    xbt = xs_transaction_start(xenstore);
+    if (xbt == XBT_NULL) {
+        goto abort_transaction;
+    }
+
+    if (xenstore_write_int(vtpmdev->xendev.fe, "ring-ref",
+                           vtpmdev->ring_ref)) {
+        goto abort_transaction;
+    }
+
+    if (xenstore_write_int(vtpmdev->xendev.fe, "event-channel",
+                           vtpmdev->xendev.local_port)) {
+        goto abort_transaction;
+    }
+
+    /* Publish protocol v2 feature */
+    if (xenstore_write_int(vtpmdev->xendev.fe, "feature-protocol-v2", 1)) {
+        goto abort_transaction;
+    }
+
+    if (!xs_transaction_end(xenstore, xbt, 0)) {
+        if (errno == EAGAIN) {
+            goto again;
+        }
+    }
+    /* Tell vtpm backend that we are ready */
+    xenbus_switch_state(&vtpmdev->xendev, XenbusStateInitialised);
+
+    return 0;
+
+abort_transaction:
+    xc_gntshr_munmap(vtpmdev->xen_xcs, vtpmdev->shr, 1);
+    xs_transaction_end(xenstore, xbt, 1);
+    return -1;
+}
+
+static int vtpm_free(struct XenDevice *xendev)
+{
+    struct xen_vtpm_dev *vtpmdev = container_of(xendev, struct xen_vtpm_dev,
+                                                xendev);
+    aio_poll(vtpm_aio_ctx, false);
+    qemu_bh_delete(vtpmdev->sr_bh);
+    if (vtpmdev->shr) {
+        xc_gntshr_munmap(vtpmdev->xen_xcs, vtpmdev->shr, 1);
+    }
+    xc_interface_close(vtpmdev->xen_xcs);
+    return 0;
+}
+
+static void vtpm_alloc(struct XenDevice *xendev)
+{
+    struct xen_vtpm_dev *vtpmdev = container_of(xendev, struct xen_vtpm_dev,
+                                                xendev);
+
+    vtpm_aio_ctx = aio_context_new(NULL);
+    if (vtpm_aio_ctx == NULL) {
+        return;
+    }
+    vtpmdev->sr_bh = aio_bh_new(vtpm_aio_ctx, sr_bh_handler, vtpmdev);
+    qemu_bh_schedule(vtpmdev->sr_bh);
+    vtpmdev->xen_xcs = xen_xc_gntshr_open(0, 0);
+}
+
+static void vtpm_event(struct XenDevice *xendev)
+{
+    struct xen_vtpm_dev *vtpmdev = container_of(xendev, struct xen_vtpm_dev,
+                                                xendev);
+
+    qemu_bh_schedule(vtpmdev->sr_bh);
+}
+
+struct XenDevOps xen_vtpmdev_ops = {
+    .size             = sizeof(struct xen_vtpm_dev),
+    .flags            = DEVOPS_FLAG_IGNORE_STATE |
+                        DEVOPS_FLAG_FE,
+    .event            = vtpm_event,
+    .free             = vtpm_free,
+    .alloc            = vtpm_alloc,
+    .initialise       = vtpm_initialise,
+    .backend_changed  = vtpm_backend_changed,
+};
diff --git a/hw/xen/xen_backend.c b/hw/xen/xen_backend.c
index ad6e324..377a9c8 100644
--- a/hw/xen/xen_backend.c
+++ b/hw/xen/xen_backend.c
@@ -741,6 +741,20 @@ int xen_be_register(const char *type, struct XenDevOps 
*ops)
     return xenstore_scan(type, xen_domid, ops);
 }
 
+int xen_be_alloc_unbound(struct XenDevice *xendev, int dom, int remote_dom)
+{
+    xendev->local_port = xc_evtchn_bind_unbound_port(xendev->evtchndev,
+                                                     remote_dom);
+    if (xendev->local_port == -1) {
+        xen_be_printf(xendev, 0, "xc_evtchn_alloc_unbound failed\n");
+        return -1;
+    }
+    xen_be_printf(xendev, 2, "bind evtchn port %d\n", xendev->local_port);
+    qemu_set_fd_handler(xc_evtchn_fd(xendev->evtchndev),
+                        xen_be_evtchn_event, NULL, xendev);
+    return 0;
+}
+
 int xen_be_bind_evtchn(struct XenDevice *xendev)
 {
     if (xendev->local_port != -1) {
@@ -813,6 +827,26 @@ void xen_be_printf(struct XenDevice *xendev, int 
msg_level, const char *fmt, ...
     qemu_log_flush();
 }
 
+void vtpm_backend_changed(struct XenDevice *xendev, const char *node)
+{
+    int be_state;
+
+    if (strcmp(node, "state") == 0) {
+        xenstore_read_be_int(xendev, node, &be_state);
+        switch (be_state) {
+        case XenbusStateConnected:
+            /*TODO*/
+            break;
+        case XenbusStateClosing:
+        case XenbusStateClosed:
+            xenbus_switch_state(xendev, XenbusStateClosing);
+            break;
+        default:
+            break;
+        }
+    }
+}
+
 void xen_qtail_insert_xendev(struct XenDevice *xendev)
 {
     QTAILQ_INSERT_TAIL(&xendevs, xendev, next);
diff --git a/include/hw/xen/xen_backend.h b/include/hw/xen/xen_backend.h
index 06e202f..d07ae36 100644
--- a/include/hw/xen/xen_backend.h
+++ b/include/hw/xen/xen_backend.h
@@ -102,8 +102,12 @@ char *xenstore_fe_read_be_str(const char *type, int dom, 
int dev);
 int xenbus_switch_state(struct XenDevice *xendev, enum xenbus_state xbus);
 struct XenDevice *xen_fe_get_xendev(const char *type, int dom, int dev,
                                     struct XenDevOps *ops);
-void xenstore_fe_update(char *watch, char *type, int dom,
-                        struct XenDevOps *ops);
+void xenstore_fe_update(char *watch, char *type, int dom, struct XenDevOps 
*ops);
+
+/*Xen vtpm*/
+int vtpm_send(struct XenDevice *xendev, uint8_t* buf, size_t count);
+int vtpm_recv(struct XenDevice *xendev, uint8_t* buf, size_t *count);
+void vtpm_backend_changed(struct XenDevice *xendev, const char *node);
 
 /* actual backend drivers */
 extern struct XenDevOps xen_console_ops;      /* xen_console.c     */
@@ -111,6 +115,7 @@ extern struct XenDevOps xen_kbdmouse_ops;     /* 
xen_framebuffer.c */
 extern struct XenDevOps xen_framebuffer_ops;  /* xen_framebuffer.c */
 extern struct XenDevOps xen_blkdev_ops;       /* xen_disk.c        */
 extern struct XenDevOps xen_netdev_ops;       /* xen_nic.c         */
+extern struct XenDevOps xen_vtpmdev_ops;      /* xen_vtpm_frontend.c*/
 
 void xen_init_display(int domid);
 
diff --git a/include/hw/xen/xen_common.h b/include/hw/xen/xen_common.h
index 07731b9..2e9bb62 100644
--- a/include/hw/xen/xen_common.h
+++ b/include/hw/xen/xen_common.h
@@ -130,6 +130,12 @@ static inline XenXC xen_xc_interface_open(void *logger, 
void *dombuild_logger,
     return xc_interface_open(logger, dombuild_logger, open_flags);
 }
 
+static inline xc_gntshr *xen_xc_gntshr_open(void *logger,
+                                           unsigned int open_flags)
+{
+    return xc_gntshr_open(logger, open_flags);
+}
+
 /* FIXME There is now way to have the xen fd */
 static inline int xc_fd(xc_interface *xen_xc)
 {
diff --git a/xen-hvm.c b/xen-hvm.c
index 05e522c..5b93cd4 100644
--- a/xen-hvm.c
+++ b/xen-hvm.c
@@ -986,6 +986,12 @@ int xen_hvm_init(ram_addr_t *below_4g_mem_size, ram_addr_t 
*above_4g_mem_size,
     int i, rc;
     unsigned long ioreq_pfn;
     unsigned long bufioreq_evtchn;
+
+#ifdef CONFIG_TPM_XENSTUBDOMS
+    char path[XEN_BUFSIZE];
+    unsigned int stubdom_vtpm = 0;
+#endif
+
     XenIOState *state;
 
     state = g_malloc0(sizeof (XenIOState));
@@ -1071,6 +1077,16 @@ int xen_hvm_init(ram_addr_t *below_4g_mem_size, 
ram_addr_t *above_4g_mem_size,
         fprintf(stderr, "%s: xen backend core setup failed\n", __FUNCTION__);
         return -1;
     }
+
+#ifdef CONFIG_TPM_XENSTUBDOMS
+    snprintf(path, sizeof(path), "/local/domain/%d/platform/acpi_stubdom_vtpm",
+             xen_domid);
+    xs_read(state->xenstore, 0, path, &stubdom_vtpm);
+    if (stubdom_vtpm) {
+        xen_fe_register("vtpm", &xen_vtpmdev_ops);
+    }
+#endif
+
     xen_be_register("console", &xen_console_ops);
     xen_be_register("vkbd", &xen_kbdmouse_ops);
     xen_be_register("qdisk", &xen_blkdev_ops);
-- 
1.8.3.2


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