Merge tag 'pull-xenfv.for-upstream-20231107' of git://git.infradead.org/users/dwmw2/qemu into staging

Xen PV guest support for 8.2

Add Xen PV console and network support, the former of which enables the
Xen "PV shim" to be used to support PV guests.

Also clean up the block support and make it work when the user passes
just 'drive file=IMAGE,if=xen' on the command line.

Update the documentation to reflect all of these, taking the opportunity
to simplify what it says about q35 by making unplug work for AHCI.

Ignore the VCPU_SSHOTTMR_future timer flag, and advertise the 'fixed'
per-vCPU upcall vector support, as newer upstream Xen do.

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# gpg: Signature made Tue 07 Nov 2023 17:13:21 HKT
# gpg:                using RSA key BE07D9FD54809AB2C4B0FF5F63762CDA67E2F359
# gpg:                issuer "dwmw2@infradead.org"
# gpg: Good signature from "David Woodhouse <dwmw2@infradead.org>" [unknown]
# gpg:                 aka "David Woodhouse <dwmw2@exim.org>" [unknown]
# gpg:                 aka "David Woodhouse <david@woodhou.se>" [unknown]
# gpg:                 aka "David Woodhouse <dwmw2@kernel.org>" [unknown]
# gpg: WARNING: The key's User ID is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: BE07 D9FD 5480 9AB2 C4B0  FF5F 6376 2CDA 67E2 F359

* tag 'pull-xenfv.for-upstream-20231107' of git://git.infradead.org/users/dwmw2/qemu:
  docs: update Xen-on-KVM documentation
  xen-platform: unplug AHCI disks
  hw/i386/pc: support '-nic' for xen-net-device
  hw/xen: update Xen PV NIC to XenDevice model
  hw/xen: only remove peers of PCI NICs on unplug
  hw/xen: add support for Xen primary console in emulated mode
  hw/xen: update Xen console to XenDevice model
  hw/xen: do not repeatedly try to create a failing backend device
  hw/xen: add get_frontend_path() method to XenDeviceClass
  hw/xen: automatically assign device index to block devices
  hw/xen: populate store frontend nodes with XenStore PFN/port
  i386/xen: advertise XEN_HVM_CPUID_UPCALL_VECTOR in CPUID
  include: update Xen public headers to Xen 4.17.2 release
  hw/xen: Clean up event channel 'type_val' handling to use union
  i386/xen: Ignore VCPU_SSHOTTMR_future flag in set_singleshot_timer()

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

10 files changed, 62 insertions, 189 deletions

diff --git a/include/hw/xen/interface/io/blkif.h b/include/hw/xen/interface/io/blkif.h
index 4cdba79aba..22f1eef0c0 100644
--- a/include/hw/xen/interface/io/blkif.h
+++ b/include/hw/xen/interface/io/blkif.h
@@ -1,26 +1,9 @@
+/* SPDX-License-Identifier: MIT */
 /******************************************************************************
  * blkif.h
  *
  * Unified block-device I/O interface for Xen guest OSes.
  *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to
- * deal in the Software without restriction, including without limitation the
- * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
- * sell copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- *
  * Copyright (c) 2003-2004, Keir Fraser
  * Copyright (c) 2012, Spectra Logic Corporation
  */
@@ -363,6 +346,14 @@
  *      that the frontend requires that the logical block size is 512 as it
  *      is hardcoded (which is the case in some frontend implementations).
  *
+ * trusted
+ *      Values:         0/1 (boolean)
+ *      Default value:  1
+ *
+ *      A value of "0" indicates that the frontend should not trust the
+ *      backend, and should deploy whatever measures available to protect from
+ *      a malicious backend on the other end.
+ *
  *------------------------- Virtual Device Properties -------------------------
  *
  * device-type
diff --git a/include/hw/xen/interface/io/console.h b/include/hw/xen/interface/io/console.h
index 4811f47220..4509b4b689 100644
--- a/include/hw/xen/interface/io/console.h
+++ b/include/hw/xen/interface/io/console.h
@@ -1,26 +1,9 @@
+/* SPDX-License-Identifier: MIT */
 /******************************************************************************
  * console.h
  *
  * Console I/O interface for Xen guest OSes.
  *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to
- * deal in the Software without restriction, including without limitation the
- * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
- * sell copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- *
  * Copyright (c) 2005, Keir Fraser
  */
 
diff --git a/include/hw/xen/interface/io/fbif.h b/include/hw/xen/interface/io/fbif.h
index cc25aab32e..93c73195d8 100644
--- a/include/hw/xen/interface/io/fbif.h
+++ b/include/hw/xen/interface/io/fbif.h
@@ -1,24 +1,7 @@
+/* SPDX-License-Identifier: MIT */
 /*
  * fbif.h -- Xen virtual frame buffer device
  *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to
- * deal in the Software without restriction, including without limitation the
- * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
- * sell copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- *
  * Copyright (C) 2005 Anthony Liguori <aliguori@us.ibm.com>
  * Copyright (C) 2006 Red Hat, Inc., Markus Armbruster <armbru@redhat.com>
  */
diff --git a/include/hw/xen/interface/io/kbdif.h b/include/hw/xen/interface/io/kbdif.h
index a6b01c52c7..4bde6b3821 100644
--- a/include/hw/xen/interface/io/kbdif.h
+++ b/include/hw/xen/interface/io/kbdif.h
@@ -1,24 +1,7 @@
+/* SPDX-License-Identifier: MIT */
 /*
  * kbdif.h -- Xen virtual keyboard/mouse
  *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to
- * deal in the Software without restriction, including without limitation the
- * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
- * sell copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- *
  * Copyright (C) 2005 Anthony Liguori <aliguori@us.ibm.com>
  * Copyright (C) 2006 Red Hat, Inc., Markus Armbruster <armbru@redhat.com>
  */
diff --git a/include/hw/xen/interface/io/netif.h b/include/hw/xen/interface/io/netif.h
index 00dd258712..c13b85061d 100644
--- a/include/hw/xen/interface/io/netif.h
+++ b/include/hw/xen/interface/io/netif.h
@@ -1,26 +1,9 @@
+/* SPDX-License-Identifier: MIT */
 /******************************************************************************
  * netif.h
  *
  * Unified network-device I/O interface for Xen guest OSes.
  *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to
- * deal in the Software without restriction, including without limitation the
- * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
- * sell copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- *
  * Copyright (c) 2003-2004, Keir Fraser
  */
 
@@ -161,6 +144,12 @@
  */
 
 /*
+ * The setting of "trusted" node to "0" in the frontend path signals that the
+ * frontend should not trust the backend, and should deploy whatever measures
+ * available to protect from a malicious backend on the other end.
+ */
+
+/*
  * Control ring
  * ============
  *
diff --git a/include/hw/xen/interface/io/protocols.h b/include/hw/xen/interface/io/protocols.h
index 52b4de0f81..7815e1ff0f 100644
--- a/include/hw/xen/interface/io/protocols.h
+++ b/include/hw/xen/interface/io/protocols.h
@@ -1,24 +1,7 @@
+/* SPDX-License-Identifier: MIT */
 /******************************************************************************
  * protocols.h
  *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to
- * deal in the Software without restriction, including without limitation the
- * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
- * sell copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- *
  * Copyright (c) 2008, Keir Fraser
  */
 
diff --git a/include/hw/xen/interface/io/ring.h b/include/hw/xen/interface/io/ring.h
index c486c457e0..025939278b 100644
--- a/include/hw/xen/interface/io/ring.h
+++ b/include/hw/xen/interface/io/ring.h
@@ -1,26 +1,9 @@
+/* SPDX-License-Identifier: MIT */
 /******************************************************************************
  * ring.h
  *
  * Shared producer-consumer ring macros.
  *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to
- * deal in the Software without restriction, including without limitation the
- * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
- * sell copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- *
  * Tim Deegan and Andrew Warfield November 2004.
  */
 
@@ -95,9 +78,8 @@ typedef unsigned int RING_IDX;
  * of the shared memory area (PAGE_SIZE, for instance). To initialise
  * the front half:
  *
- *     mytag_front_ring_t front_ring;
- *     SHARED_RING_INIT((mytag_sring_t *)shared_page);
- *     FRONT_RING_INIT(&front_ring, (mytag_sring_t *)shared_page, PAGE_SIZE);
+ *     mytag_front_ring_t ring;
+ *     XEN_FRONT_RING_INIT(&ring, (mytag_sring_t *)shared_page, PAGE_SIZE);
  *
  * Initializing the back follows similarly (note that only the front
  * initializes the shared ring):
@@ -184,6 +166,11 @@ typedef struct __name##_back_ring __name##_back_ring_t
 
 #define FRONT_RING_INIT(_r, _s, __size) FRONT_RING_ATTACH(_r, _s, 0, __size)
 
+#define XEN_FRONT_RING_INIT(r, s, size) do {                            \
+    SHARED_RING_INIT(s);                                                \
+    FRONT_RING_INIT(r, s, size);                                        \
+} while (0)
+
 #define BACK_RING_ATTACH(_r, _s, _i, __size) do {                       \
     (_r)->rsp_prod_pvt = (_i);                                          \
     (_r)->req_cons = (_i);                                              \
@@ -208,11 +195,11 @@ typedef struct __name##_back_ring __name##_back_ring_t
     (RING_FREE_REQUESTS(_r) == 0)
 
 /* Test if there are outstanding messages to be processed on a ring. */
-#define RING_HAS_UNCONSUMED_RESPONSES(_r)                               \
+#define XEN_RING_NR_UNCONSUMED_RESPONSES(_r)                            \
     ((_r)->sring->rsp_prod - (_r)->rsp_cons)
 
 #ifdef __GNUC__
-#define RING_HAS_UNCONSUMED_REQUESTS(_r) ({                             \
+#define XEN_RING_NR_UNCONSUMED_REQUESTS(_r) ({                          \
     unsigned int req = (_r)->sring->req_prod - (_r)->req_cons;          \
     unsigned int rsp = RING_SIZE(_r) -                                  \
         ((_r)->req_cons - (_r)->rsp_prod_pvt);                          \
@@ -220,13 +207,27 @@ typedef struct __name##_back_ring __name##_back_ring_t
 })
 #else
 /* Same as above, but without the nice GCC ({ ... }) syntax. */
-#define RING_HAS_UNCONSUMED_REQUESTS(_r)                                \
+#define XEN_RING_NR_UNCONSUMED_REQUESTS(_r)                             \
     ((((_r)->sring->req_prod - (_r)->req_cons) <                        \
       (RING_SIZE(_r) - ((_r)->req_cons - (_r)->rsp_prod_pvt))) ?        \
      ((_r)->sring->req_prod - (_r)->req_cons) :                         \
      (RING_SIZE(_r) - ((_r)->req_cons - (_r)->rsp_prod_pvt)))
 #endif
 
+#ifdef XEN_RING_HAS_UNCONSUMED_IS_BOOL
+/*
+ * These variants should only be used in case no caller is abusing them for
+ * obtaining the number of unconsumed responses/requests.
+ */
+#define RING_HAS_UNCONSUMED_RESPONSES(_r) \
+    (!!XEN_RING_NR_UNCONSUMED_RESPONSES(_r))
+#define RING_HAS_UNCONSUMED_REQUESTS(_r)  \
+    (!!XEN_RING_NR_UNCONSUMED_REQUESTS(_r))
+#else
+#define RING_HAS_UNCONSUMED_RESPONSES(_r) XEN_RING_NR_UNCONSUMED_RESPONSES(_r)
+#define RING_HAS_UNCONSUMED_REQUESTS(_r)  XEN_RING_NR_UNCONSUMED_REQUESTS(_r)
+#endif
+
 /* Direct access to individual ring elements, by index. */
 #define RING_GET_REQUEST(_r, _idx)                                      \
     (&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].req))
diff --git a/include/hw/xen/interface/io/usbif.h b/include/hw/xen/interface/io/usbif.h
index c0a552e195..875af0dc7c 100644
--- a/include/hw/xen/interface/io/usbif.h
+++ b/include/hw/xen/interface/io/usbif.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: MIT */
 /*
  * usbif.h
  *
@@ -5,24 +6,6 @@
  *
  * Copyright (C) 2009, FUJITSU LABORATORIES LTD.
  * Author: Noboru Iwamatsu <n_iwamatsu@jp.fujitsu.com>
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to
- * deal in the Software without restriction, including without limitation the
- * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
- * sell copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
  */
 
 #ifndef __XEN_PUBLIC_IO_USBIF_H__
diff --git a/include/hw/xen/interface/io/xenbus.h b/include/hw/xen/interface/io/xenbus.h
index 927f9db552..9cd0cd7c67 100644
--- a/include/hw/xen/interface/io/xenbus.h
+++ b/include/hw/xen/interface/io/xenbus.h
@@ -1,26 +1,9 @@
+/* SPDX-License-Identifier: MIT */
 /*****************************************************************************
  * xenbus.h
  *
  * Xenbus protocol details.
  *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to
- * deal in the Software without restriction, including without limitation the
- * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
- * sell copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- *
  * Copyright (C) 2005 XenSource Ltd.
  */
 
diff --git a/include/hw/xen/interface/io/xs_wire.h b/include/hw/xen/interface/io/xs_wire.h
index 4dd6632669..04e6849feb 100644
--- a/include/hw/xen/interface/io/xs_wire.h
+++ b/include/hw/xen/interface/io/xs_wire.h
@@ -1,25 +1,8 @@
+/* SPDX-License-Identifier: MIT */
 /*
  * Details of the "wire" protocol between Xen Store Daemon and client
  * library or guest kernel.
  *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to
- * deal in the Software without restriction, including without limitation the
- * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
- * sell copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- *
  * Copyright (C) 2005 Rusty Russell IBM Corporation
  */
 
@@ -71,11 +54,12 @@ struct xsd_errors
 #ifdef EINVAL
 #define XSD_ERROR(x) { x, #x }
 /* LINTED: static unused */
-static struct xsd_errors xsd_errors[]
+static const struct xsd_errors xsd_errors[]
 #if defined(__GNUC__)
 __attribute__((unused))
 #endif
     = {
+    /* /!\ New errors should be added at the end of the array. */
     XSD_ERROR(EINVAL),
     XSD_ERROR(EACCES),
     XSD_ERROR(EEXIST),
@@ -90,7 +74,8 @@ __attribute__((unused))
     XSD_ERROR(EBUSY),
     XSD_ERROR(EAGAIN),
     XSD_ERROR(EISCONN),
-    XSD_ERROR(E2BIG)
+    XSD_ERROR(E2BIG),
+    XSD_ERROR(EPERM),
 };
 #endif
 
@@ -124,6 +109,7 @@ struct xenstore_domain_interface {
     XENSTORE_RING_IDX rsp_cons, rsp_prod;
     uint32_t server_features; /* Bitmap of features supported by the server */
     uint32_t connection;
+    uint32_t error;
 };
 
 /* Violating this is very bad.  See docs/misc/xenstore.txt. */
@@ -135,10 +121,18 @@ struct xenstore_domain_interface {
 
 /* The ability to reconnect a ring */
 #define XENSTORE_SERVER_FEATURE_RECONNECTION 1
+/* The presence of the "error" field in the ring page */
+#define XENSTORE_SERVER_FEATURE_ERROR        2
 
 /* Valid values for the connection field */
 #define XENSTORE_CONNECTED 0 /* the steady-state */
-#define XENSTORE_RECONNECT 1 /* guest has initiated a reconnect */
+#define XENSTORE_RECONNECT 1 /* reconnect in progress */
+
+/* Valid values for the error field */
+#define XENSTORE_ERROR_NONE    0 /* No error */
+#define XENSTORE_ERROR_COMM    1 /* Communication problem */
+#define XENSTORE_ERROR_RINGIDX 2 /* Invalid ring index */
+#define XENSTORE_ERROR_PROTO   3 /* Protocol violation (payload too long) */
 
 #endif /* _XS_WIRE_H */