Merge branch 'xenfv-kvm-15' of git://git.infradead.org/users/dwmw2/qemu into HEAD

This adds support for emulating Xen under Linux/KVM, based on kernel
patches which have been present since Linux v5.12. As with the kernel
support, it's derived from work started by João Martins of Oracle in
2018.

This series just adds the basic platform support — CPUID, hypercalls,
event channels, a stub of XenStore.

A full single-tenant internal implementation of XenStore, and patches
to make QEMU's Xen PV drivers work with this Xen emulation, are waiting
in the wings to be submitted in a follow-on patch series.

As noted in the documentation, it's enabled by setting the xen-version
property on the KVM accelerator, e.g.:

 qemu-system-x86_64 -serial mon:stdio -M q35 -display none -m 1G -smp 2 \
    -accel kvm,xen-version=0x4000e,kernel-irqchip=split \
    -kernel vmlinuz-6.0.7-301.fc37.x86_64 \
    -append "console=ttyS0 root=/dev/sda1" \
    -drive file=/var/lib/libvirt/images/fedora28.qcow2,if=none,id=disk \
    -device ahci,id=ahci -device ide-hd,drive=disk,bus=ahci.0

Even before this was merged, we've already been using it to find and fix
bugs in the Linux kernel Xen guest support:

https://lore.kernel.org/all/4bffa69a949bfdc92c4a18e5a1c3cbb3b94a0d32.camel@infradead.org/
https://lore.kernel.org/all/871qnunycr.ffs@tglx/

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 80 insertions, 0 deletions

diff --git a/include/exec/replay-core.h b/include/exec/replay-core.h
new file mode 100644
index 0000000000..244c77acce
--- /dev/null
+++ b/include/exec/replay-core.h
@@ -0,0 +1,80 @@
+/*
+ * QEMU replay core API
+ *
+ * Copyright (c) 2010-2015 Institute for System Programming
+ *                         of the Russian Academy of Sciences.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef EXEC_REPLAY_H
+#define EXEC_REPLAY_H
+
+#include "qapi/qapi-types-replay.h"
+
+extern ReplayMode replay_mode;
+
+/* Replay process control functions */
+
+/* Enables recording or saving event log with specified parameters */
+void replay_configure(struct QemuOpts *opts);
+/* Initializes timers used for snapshotting and enables events recording */
+void replay_start(void);
+/* Closes replay log file and frees other resources. */
+void replay_finish(void);
+/* Adds replay blocker with the specified error description */
+void replay_add_blocker(const char *feature);
+/* Returns name of the replay log file */
+const char *replay_get_filename(void);
+
+/*
+ * Start making one step in backward direction.
+ * Used by gdbstub for backwards debugging.
+ * Returns true on success.
+ */
+bool replay_reverse_step(void);
+/*
+ * Start searching the last breakpoint/watchpoint.
+ * Used by gdbstub for backwards debugging.
+ * Returns true if the process successfully started.
+ */
+bool replay_reverse_continue(void);
+/*
+ * Returns true if replay module is processing
+ * reverse_continue or reverse_step request
+ */
+bool replay_running_debug(void);
+/* Called in reverse debugging mode to collect breakpoint information */
+void replay_breakpoint(void);
+/* Called when gdb is attached to gdbstub */
+void replay_gdb_attached(void);
+
+/* Interrupts and exceptions */
+
+/* Called by exception handler to write or read exception processing events */
+bool replay_exception(void);
+/*
+ * Used to determine that exception is pending.
+ * Does not proceed to the next event in the log.
+ */
+bool replay_has_exception(void);
+/*
+ * Called by interrupt handlers to write or read interrupt processing events.
+ * Returns true if interrupt should be processed.
+ */
+bool replay_interrupt(void);
+/*
+ * Tries to read interrupt event from the file.
+ * Returns true, when interrupt request is pending.
+ */
+bool replay_has_interrupt(void);
+
+/* Processing data from random generators */
+
+/* Saves the values from the random number generator */
+void replay_save_random(int ret, void *buf, size_t len);
+/* Loads the saved values for the random number generator */
+int replay_read_random(void *buf, size_t len);
+
+#endif