6 files changed, 73 insertions, 8 deletions
diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index 8830546121..2417597236 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -398,6 +398,9 @@ struct CPUState {
     uint32_t kvm_fetch_index;
     uint64_t dirty_pages;
 
+    /* Use by accel-block: CPU is executing an ioctl() */
+    QemuLockCnt in_ioctl_lock;
+
     /* Used for events with 'vcpu' and *without* the 'disabled' properties */
     DECLARE_BITMAP(trace_dstate_delayed, CPU_TRACE_DSTATE_MAX_EVENTS);
     DECLARE_BITMAP(trace_dstate, CPU_TRACE_DSTATE_MAX_EVENTS);
diff --git a/include/hw/xen/xen-bus-helper.h b/include/hw/xen/xen-bus-helper.h
index 629a904d1a..8782f30550 100644
--- a/include/hw/xen/xen-bus-helper.h
+++ b/include/hw/xen/xen-bus-helper.h
@@ -31,10 +31,12 @@ void xs_node_printf(struct xs_handle *xsh,  xs_transaction_t tid,
 /* Read from node/key unless node is empty, in which case read from key */
 int xs_node_vscanf(struct xs_handle *xsh,  xs_transaction_t tid,
                    const char *node, const char *key, Error **errp,
-                   const char *fmt, va_list ap);
+                   const char *fmt, va_list ap)
+    G_GNUC_SCANF(6, 0);
 int xs_node_scanf(struct xs_handle *xsh,  xs_transaction_t tid,
                   const char *node, const char *key, Error **errp,
-                  const char *fmt, ...);
+                  const char *fmt, ...)
+    G_GNUC_SCANF(6, 7);
 
 /* Watch node/key unless node is empty, in which case watch key */
 void xs_node_watch(struct xs_handle *xsh, const char *node, const char *key,
diff --git a/include/hw/xen/xen-bus.h b/include/hw/xen/xen-bus.h
index 713e763348..4d966a2dbb 100644
--- a/include/hw/xen/xen-bus.h
+++ b/include/hw/xen/xen-bus.h
@@ -94,7 +94,8 @@ void xen_device_frontend_printf(XenDevice *xendev, const char *key,
     G_GNUC_PRINTF(3, 4);
 
 int xen_device_frontend_scanf(XenDevice *xendev, const char *key,
-                              const char *fmt, ...);
+                              const char *fmt, ...)
+    G_GNUC_SCANF(3, 4);
 
 void xen_device_set_max_grant_refs(XenDevice *xendev, unsigned int nr_refs,
                                    Error **errp);
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index 7d059ad526..bd23a08595 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -427,11 +427,6 @@ void qemu_anon_ram_free(void *ptr, size_t size);
 #define HAVE_CHARDEV_SERIAL 1
 #endif
 
-#if defined(__linux__) || defined(__FreeBSD__) ||               \
-    defined(__FreeBSD_kernel__) || defined(__DragonFly__)
-#define HAVE_CHARDEV_PARPORT 1
-#endif
-
 #if defined(__HAIKU__)
 #define SIGIO SIGPOLL
 #endif
diff --git a/include/sysemu/accel-blocker.h b/include/sysemu/accel-blocker.h
new file mode 100644
index 0000000000..72020529ef
--- /dev/null
+++ b/include/sysemu/accel-blocker.h
@@ -0,0 +1,56 @@
+/*
+ * Accelerator blocking API, to prevent new ioctls from starting and wait the
+ * running ones finish.
+ * This mechanism differs from pause/resume_all_vcpus() in that it does not
+ * release the BQL.
+ *
+ *  Copyright (c) 2022 Red Hat Inc.
+ *
+ * Author: Emanuele Giuseppe Esposito       <eesposit@redhat.com>
+ *
+ * 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 ACCEL_BLOCKER_H
+#define ACCEL_BLOCKER_H
+
+#include "qemu/osdep.h"
+#include "sysemu/cpus.h"
+
+extern void accel_blocker_init(void);
+
+/*
+ * accel_{cpu_}ioctl_begin/end:
+ * Mark when ioctl is about to run or just finished.
+ *
+ * accel_{cpu_}ioctl_begin will block after accel_ioctl_inhibit_begin() is
+ * called, preventing new ioctls to run. They will continue only after
+ * accel_ioctl_inibith_end().
+ */
+extern void accel_ioctl_begin(void);
+extern void accel_ioctl_end(void);
+extern void accel_cpu_ioctl_begin(CPUState *cpu);
+extern void accel_cpu_ioctl_end(CPUState *cpu);
+
+/*
+ * accel_ioctl_inhibit_begin: start critical section
+ *
+ * This function makes sure that:
+ * 1) incoming accel_{cpu_}ioctl_begin() calls block
+ * 2) wait that all ioctls that were already running reach
+ *    accel_{cpu_}ioctl_end(), kicking vcpus if necessary.
+ *
+ * This allows the caller to access shared data or perform operations without
+ * worrying of concurrent vcpus accesses.
+ */
+extern void accel_ioctl_inhibit_begin(void);
+
+/*
+ * accel_ioctl_inhibit_end: end critical section started by
+ * accel_ioctl_inhibit_begin()
+ *
+ * This function allows blocked accel_{cpu_}ioctl_begin() to continue.
+ */
+extern void accel_ioctl_inhibit_end(void);
+
+#endif /* ACCEL_BLOCKER_H */
diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h
index 3b4adcdc10..60b520a13e 100644
--- a/include/sysemu/kvm_int.h
+++ b/include/sysemu/kvm_int.h
@@ -12,6 +12,7 @@
 #include "exec/memory.h"
 #include "qapi/qapi-types-common.h"
 #include "qemu/accel.h"
+#include "qemu/queue.h"
 #include "sysemu/kvm.h"
 
 typedef struct KVMSlot
@@ -31,10 +32,17 @@ typedef struct KVMSlot
     ram_addr_t ram_start_offset;
 } KVMSlot;
 
+typedef struct KVMMemoryUpdate {
+    QSIMPLEQ_ENTRY(KVMMemoryUpdate) next;
+    MemoryRegionSection section;
+} KVMMemoryUpdate;
+
 typedef struct KVMMemoryListener {
     MemoryListener listener;
     KVMSlot *slots;
     int as_id;
+    QSIMPLEQ_HEAD(, KVMMemoryUpdate) transaction_add;
+    QSIMPLEQ_HEAD(, KVMMemoryUpdate) transaction_del;
 } KVMMemoryListener;
 
 #define KVM_MSI_HASHTAB_SIZE    256