From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Wed, 22 Mar 2017 13:59:44 +0000 (+0100)
Subject: libxl: preserve console tty across soft reset
X-Git-Tag: archive/raspbian/4.11.1-1+rpi1~1^2~66^2~2421
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=841e86b8e11bc1afa625f18af7b7757d278bd20e;p=xen.git

libxl: preserve console tty across soft reset

On soft reset we remove the domain from xenstore and introduce it back to
have everything reconnected. Console, however, stays attached (as xenconsoled
checks if the domain is dying and our domain is not) but we lose the
information about tty:

before soft reset:
   console = ""
    ...
    type = "xenconsoled"
    output = "pty"
    tty = "/dev/pts/1"
    ...

after:
   console = ""
    ...
    type = "xenconsoled"
    output = "pty"
    tty = ""
    ...

The issue applies to both HVM and PVH but for HVM guests serial console
through QEMU is usually in use and for PVH we don't have it.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
---

diff --git a/tools/libxl/libxl_console.c b/tools/libxl/libxl_console.c
index cbc70b7410..446e766911 100644
--- a/tools/libxl/libxl_console.c
+++ b/tools/libxl/libxl_console.c
@@ -316,7 +316,10 @@ int libxl__device_console_add(libxl__gc *gc, uint32_t domid,
     flexarray_append(ro_front, "output");
     flexarray_append(ro_front, console->output);
     flexarray_append(ro_front, "tty");
-    flexarray_append(ro_front, "");
+    if (state && state->console_tty)
+        flexarray_append(ro_front, state->console_tty);
+    else
+        flexarray_append(ro_front, "");
 
     if (state) {
         flexarray_append(ro_front, "port");
diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index 95fd96b29c..46b80b216a 100644
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -1697,6 +1697,7 @@ static int do_domain_soft_reset(libxl_ctx *ctx,
     libxl__domain_build_state *state;
     libxl__domain_save_state *dss;
     char *dom_path, *xs_store_mfn, *xs_console_mfn;
+    const char *console_tty;
     uint32_t domid_out;
     int rc;
 
@@ -1737,6 +1738,15 @@ static int do_domain_soft_reset(libxl_ctx *ctx,
     state->console_mfn = xs_console_mfn ? atol(xs_console_mfn): 0;
     free(xs_console_mfn);
 
+    rc = libxl__xs_read_mandatory(gc, XBT_NULL,
+                                  GCSPRINTF("%s/console/tty", dom_path),
+                                  &console_tty);
+    if (rc) {
+        LOGD(ERROR, domid_soft_reset, "failed to read console/tty.");
+        goto out;
+    }
+    state->console_tty = libxl__strdup(gc, console_tty);
+
     dss->ao = ao;
     dss->domid = dss->dsps.domid = domid_soft_reset;
     dss->dsps.dm_savefile = GCSPRINTF(LIBXL_DEVICE_MODEL_SAVE_FILE".%d",
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 25cb08ac2d..f1d8f9a03c 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -1123,6 +1123,7 @@ typedef struct {
     uint32_t console_port;
     uint32_t console_domid;
     unsigned long console_mfn;
+    char *console_tty;
 
     char *saved_state;