254d1a3f02
Add xs_reset_watches function to shutdown watches from old kernel after kexec boot. The old kernel does not unregister all watches in the shutdown path. They are still active, the double registration can not be detected by the new kernel. When the watches fire, unexpected events will arrive and the xenwatch thread will crash (jumps to NULL). An orderly reboot of a hvm guest will destroy the entire guest with all its resources (including the watches) before it is rebuilt from scratch, so the missing unregister is not an issue in that case. With this change the xenstored is instructed to wipe all active watches for the guest. However, a patch for xenstored is required so that it accepts the XS_RESET_WATCHES request from a client (see changeset 23839:42a45baf037d in xen-unstable.hg). Without the patch for xenstored the registration of watches will fail and some features of a PVonHVM guest are not available. The guest is still able to boot, but repeated kexec boots will fail. Signed-off-by: Olaf Hering <olaf@aepfle.de> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
94 lines
2.2 KiB
C
94 lines
2.2 KiB
C
/*
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* Details of the "wire" protocol between Xen Store Daemon and client
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* library or guest kernel.
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* Copyright (C) 2005 Rusty Russell IBM Corporation
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*/
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#ifndef _XS_WIRE_H
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#define _XS_WIRE_H
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enum xsd_sockmsg_type
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{
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XS_DEBUG,
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XS_DIRECTORY,
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XS_READ,
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XS_GET_PERMS,
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XS_WATCH,
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XS_UNWATCH,
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XS_TRANSACTION_START,
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XS_TRANSACTION_END,
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XS_INTRODUCE,
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XS_RELEASE,
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XS_GET_DOMAIN_PATH,
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XS_WRITE,
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XS_MKDIR,
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XS_RM,
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XS_SET_PERMS,
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XS_WATCH_EVENT,
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XS_ERROR,
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XS_IS_DOMAIN_INTRODUCED,
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XS_RESUME,
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XS_SET_TARGET,
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XS_RESTRICT,
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XS_RESET_WATCHES,
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};
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#define XS_WRITE_NONE "NONE"
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#define XS_WRITE_CREATE "CREATE"
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#define XS_WRITE_CREATE_EXCL "CREATE|EXCL"
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/* We hand errors as strings, for portability. */
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struct xsd_errors
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{
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int errnum;
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const char *errstring;
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};
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#define XSD_ERROR(x) { x, #x }
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static struct xsd_errors xsd_errors[] __attribute__((unused)) = {
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XSD_ERROR(EINVAL),
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XSD_ERROR(EACCES),
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XSD_ERROR(EEXIST),
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XSD_ERROR(EISDIR),
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XSD_ERROR(ENOENT),
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XSD_ERROR(ENOMEM),
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XSD_ERROR(ENOSPC),
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XSD_ERROR(EIO),
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XSD_ERROR(ENOTEMPTY),
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XSD_ERROR(ENOSYS),
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XSD_ERROR(EROFS),
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XSD_ERROR(EBUSY),
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XSD_ERROR(EAGAIN),
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XSD_ERROR(EISCONN)
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};
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struct xsd_sockmsg
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{
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uint32_t type; /* XS_??? */
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uint32_t req_id;/* Request identifier, echoed in daemon's response. */
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uint32_t tx_id; /* Transaction id (0 if not related to a transaction). */
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uint32_t len; /* Length of data following this. */
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/* Generally followed by nul-terminated string(s). */
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};
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enum xs_watch_type
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{
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XS_WATCH_PATH = 0,
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XS_WATCH_TOKEN
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};
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/* Inter-domain shared memory communications. */
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#define XENSTORE_RING_SIZE 1024
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typedef uint32_t XENSTORE_RING_IDX;
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#define MASK_XENSTORE_IDX(idx) ((idx) & (XENSTORE_RING_SIZE-1))
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struct xenstore_domain_interface {
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char req[XENSTORE_RING_SIZE]; /* Requests to xenstore daemon. */
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char rsp[XENSTORE_RING_SIZE]; /* Replies and async watch events. */
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XENSTORE_RING_IDX req_cons, req_prod;
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XENSTORE_RING_IDX rsp_cons, rsp_prod;
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};
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/* Violating this is very bad. See docs/misc/xenstore.txt. */
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#define XENSTORE_PAYLOAD_MAX 4096
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#endif /* _XS_WIRE_H */
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