Merge tag 'for-upstream' of https://gitlab.com/bonzini/qemu into staging

* Atomic memslot updates for KVM (Emanuele, David)
* libvhost-user/libvduse warnings fixes (Marcel)
* i386 TCG fixes (Joe, myself)
* Remove compilation errors when -Werror=maybe-uninitialized (Eric)
* fix GLIB_VERSION for cross-compilation (Paolo)

# -----BEGIN PGP SIGNATURE-----
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# =0b+g
# -----END PGP SIGNATURE-----
# gpg: Signature made Wed 11 Jan 2023 09:45:42 GMT
# gpg:                using RSA key F13338574B662389866C7682BFFBD25F78C7AE83
# gpg:                issuer "pbonzini@redhat.com"
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>" [full]
# gpg:                 aka "Paolo Bonzini <pbonzini@redhat.com>" [full]
# Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4  E2F7 7E15 100C CD36 69B1
#      Subkey fingerprint: F133 3857 4B66 2389 866C  7682 BFFB D25F 78C7 AE83

* tag 'for-upstream' of https://gitlab.com/bonzini/qemu: (29 commits)
  configure: remove backwards-compatibility code
  target/i386: fix operand size of unary SSE operations
  libvduse: Add extra compiler warnings
  libvhost-user: Add extra compiler warnings
  libvhost-user: Fix assignment in vring_set_avail_event
  libvduse: Fix assignment in vring_set_avail_event
  libvduse: Switch to unsigned int for inuse field in struct VduseVirtq
  libvduse: Provide _GNU_SOURCE when compiling outside of QEMU
  libvhost-user: Change dev->postcopy_ufd assignment to make it C90 compliant
  libvhost-user: Declare uffdio_register early to make it C90 compliant
  libvhost-user: Use unsigned int i for some for-loop iterations
  libvhost-user: Cast rc variable to avoid compiler warning
  libvhost-user: Replace typeof with __typeof__
  libvhost-user: Provide _GNU_SOURCE when compiling outside of QEMU
  hw/display: avoid creating empty loadable modules
  enforce use of G_GNUC_PRINTF attributes
  tests: add G_GNUC_PRINTF for various functions
  util/error: add G_GNUC_PRINTF for various functions
  tools/virtiofsd: add G_GNUC_PRINTF for logging functions
  hw/xen: use G_GNUC_PRINTF/SCANF for various functions
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

.gitlab-ci.d/crossbuild-template.yml

@@ -6,8 +6,7 @@
   script:
     - mkdir build
     - cd build
-    - PKG_CONFIG_PATH=$PKG_CONFIG_PATH
-      ../configure --enable-werror --disable-docs $QEMU_CONFIGURE_OPTS
+    - ../configure --enable-werror --disable-docs $QEMU_CONFIGURE_OPTS
         --disable-user --target-list-exclude="arm-softmmu cris-softmmu
           i386-softmmu microblaze-softmmu mips-softmmu mipsel-softmmu
           mips64-softmmu ppc-softmmu riscv32-softmmu sh4-softmmu
@@ -32,8 +31,7 @@
   script:
     - mkdir build
     - cd build
-    - PKG_CONFIG_PATH=$PKG_CONFIG_PATH
-      ../configure --enable-werror --disable-docs $QEMU_CONFIGURE_OPTS
+    - ../configure --enable-werror --disable-docs $QEMU_CONFIGURE_OPTS
         --disable-tools --enable-${ACCEL:-kvm} $EXTRA_CONFIGURE_OPTS
     - make -j$(expr $(nproc) + 1) all check-build $MAKE_CHECK_ARGS
 
@@ -44,8 +42,7 @@
   script:
     - mkdir build
     - cd build
-    - PKG_CONFIG_PATH=$PKG_CONFIG_PATH
-      ../configure --enable-werror --disable-docs $QEMU_CONFIGURE_OPTS
+    - ../configure --enable-werror --disable-docs $QEMU_CONFIGURE_OPTS
         --disable-system --target-list-exclude="aarch64_be-linux-user
           alpha-linux-user cris-linux-user m68k-linux-user microblazeel-linux-user
           nios2-linux-user or1k-linux-user ppc-linux-user sparc-linux-user

accel/accel-blocker.c

@@ -0,0 +1,154 @@
+/*
+ * Lock to inhibit accelerator ioctls
+ *
+ * Copyright (c) 2022 Red Hat Inc.
+ *
+ * Author: Emanuele Giuseppe Esposito       <eesposit@redhat.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.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/thread.h"
+#include "qemu/main-loop.h"
+#include "hw/core/cpu.h"
+#include "sysemu/accel-blocker.h"
+
+static QemuLockCnt accel_in_ioctl_lock;
+static QemuEvent accel_in_ioctl_event;
+
+void accel_blocker_init(void)
+{
+    qemu_lockcnt_init(&accel_in_ioctl_lock);
+    qemu_event_init(&accel_in_ioctl_event, false);
+}
+
+void accel_ioctl_begin(void)
+{
+    if (likely(qemu_mutex_iothread_locked())) {
+        return;
+    }
+
+    /* block if lock is taken in kvm_ioctl_inhibit_begin() */
+    qemu_lockcnt_inc(&accel_in_ioctl_lock);
+}
+
+void accel_ioctl_end(void)
+{
+    if (likely(qemu_mutex_iothread_locked())) {
+        return;
+    }
+
+    qemu_lockcnt_dec(&accel_in_ioctl_lock);
+    /* change event to SET. If event was BUSY, wake up all waiters */
+    qemu_event_set(&accel_in_ioctl_event);
+}
+
+void accel_cpu_ioctl_begin(CPUState *cpu)
+{
+    if (unlikely(qemu_mutex_iothread_locked())) {
+        return;
+    }
+
+    /* block if lock is taken in kvm_ioctl_inhibit_begin() */
+    qemu_lockcnt_inc(&cpu->in_ioctl_lock);
+}
+
+void accel_cpu_ioctl_end(CPUState *cpu)
+{
+    if (unlikely(qemu_mutex_iothread_locked())) {
+        return;
+    }
+
+    qemu_lockcnt_dec(&cpu->in_ioctl_lock);
+    /* change event to SET. If event was BUSY, wake up all waiters */
+    qemu_event_set(&accel_in_ioctl_event);
+}
+
+static bool accel_has_to_wait(void)
+{
+    CPUState *cpu;
+    bool needs_to_wait = false;
+
+    CPU_FOREACH(cpu) {
+        if (qemu_lockcnt_count(&cpu->in_ioctl_lock)) {
+            /* exit the ioctl, if vcpu is running it */
+            qemu_cpu_kick(cpu);
+            needs_to_wait = true;
+        }
+    }
+
+    return needs_to_wait || qemu_lockcnt_count(&accel_in_ioctl_lock);
+}
+
+void accel_ioctl_inhibit_begin(void)
+{
+    CPUState *cpu;
+
+    /*
+     * We allow to inhibit only when holding the BQL, so we can identify
+     * when an inhibitor wants to issue an ioctl easily.
+     */
+    g_assert(qemu_mutex_iothread_locked());
+
+    /* Block further invocations of the ioctls outside the BQL.  */
+    CPU_FOREACH(cpu) {
+        qemu_lockcnt_lock(&cpu->in_ioctl_lock);
+    }
+    qemu_lockcnt_lock(&accel_in_ioctl_lock);
+
+    /* Keep waiting until there are running ioctls */
+    while (true) {
+
+        /* Reset event to FREE. */
+        qemu_event_reset(&accel_in_ioctl_event);
+
+        if (accel_has_to_wait()) {
+            /*
+             * If event is still FREE, and there are ioctls still in progress,
+             * wait.
+             *
+             *  If an ioctl finishes before qemu_event_wait(), it will change
+             * the event state to SET. This will prevent qemu_event_wait() from
+             * blocking, but it's not a problem because if other ioctls are
+             * still running the loop will iterate once more and reset the event
+             * status to FREE so that it can wait properly.
+             *
+             * If an ioctls finishes while qemu_event_wait() is blocking, then
+             * it will be waken up, but also here the while loop makes sure
+             * to re-enter the wait if there are other running ioctls.
+             */
+            qemu_event_wait(&accel_in_ioctl_event);
+        } else {
+            /* No ioctl is running */
+            return;
+        }
+    }
+}
+
+void accel_ioctl_inhibit_end(void)
+{
+    CPUState *cpu;
+
+    qemu_lockcnt_unlock(&accel_in_ioctl_lock);
+    CPU_FOREACH(cpu) {
+        qemu_lockcnt_unlock(&cpu->in_ioctl_lock);
+    }
+}
+

accel/kvm/kvm-all.c

@@ -31,6 +31,7 @@
 #include "sysemu/kvm_int.h"
 #include "sysemu/runstate.h"
 #include "sysemu/cpus.h"
+#include "sysemu/accel-blocker.h"
 #include "qemu/bswap.h"
 #include "exec/memory.h"
 #include "exec/ram_addr.h"
@@ -46,6 +47,7 @@
 #include "sysemu/hw_accel.h"
 #include "kvm-cpus.h"
 #include "sysemu/dirtylimit.h"
+#include "qemu/range.h"
 
 #include "hw/boards.h"
 #include "monitor/stats.h"
@@ -1292,6 +1294,7 @@ void kvm_set_max_memslot_size(hwaddr max_slot_size)
     kvm_max_slot_size = max_slot_size;
 }
 
+/* Called with KVMMemoryListener.slots_lock held */
 static void kvm_set_phys_mem(KVMMemoryListener *kml,
                              MemoryRegionSection *section, bool add)
 {
@@ -1326,14 +1329,12 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
     ram = memory_region_get_ram_ptr(mr) + mr_offset;
     ram_start_offset = memory_region_get_ram_addr(mr) + mr_offset;
 
-    kvm_slots_lock();
-
     if (!add) {
         do {
             slot_size = MIN(kvm_max_slot_size, size);
             mem = kvm_lookup_matching_slot(kml, start_addr, slot_size);
             if (!mem) {
-                goto out;
+                return;
             }
             if (mem->flags & KVM_MEM_LOG_DIRTY_PAGES) {
                 /*
@@ -1371,7 +1372,7 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
             start_addr += slot_size;
             size -= slot_size;
         } while (size);
-        goto out;
+        return;
     }
 
     /* register the new slot */
@@ -1396,9 +1397,6 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
         ram += slot_size;
         size -= slot_size;
     } while (size);
-
-out:
-    kvm_slots_unlock();
 }
 
 static void *kvm_dirty_ring_reaper_thread(void *data)
@@ -1455,18 +1453,95 @@ static void kvm_region_add(MemoryListener *listener,
                            MemoryRegionSection *section)
 {
     KVMMemoryListener *kml = container_of(listener, KVMMemoryListener, listener);
+    KVMMemoryUpdate *update;
 
-    memory_region_ref(section->mr);
-    kvm_set_phys_mem(kml, section, true);
+    update = g_new0(KVMMemoryUpdate, 1);
+    update->section = *section;
+
+    QSIMPLEQ_INSERT_TAIL(&kml->transaction_add, update, next);
 }
 
 static void kvm_region_del(MemoryListener *listener,
                            MemoryRegionSection *section)
 {
     KVMMemoryListener *kml = container_of(listener, KVMMemoryListener, listener);
+    KVMMemoryUpdate *update;
 
-    kvm_set_phys_mem(kml, section, false);
-    memory_region_unref(section->mr);
+    update = g_new0(KVMMemoryUpdate, 1);
+    update->section = *section;
+
+    QSIMPLEQ_INSERT_TAIL(&kml->transaction_del, update, next);
+}
+
+static void kvm_region_commit(MemoryListener *listener)
+{
+    KVMMemoryListener *kml = container_of(listener, KVMMemoryListener,
+                                          listener);
+    KVMMemoryUpdate *u1, *u2;
+    bool need_inhibit = false;
+
+    if (QSIMPLEQ_EMPTY(&kml->transaction_add) &&
+        QSIMPLEQ_EMPTY(&kml->transaction_del)) {
+        return;
+    }
+
+    /*
+     * We have to be careful when regions to add overlap with ranges to remove.
+     * We have to simulate atomic KVM memslot updates by making sure no ioctl()
+     * is currently active.
+     *
+     * The lists are order by addresses, so it's easy to find overlaps.
+     */
+    u1 = QSIMPLEQ_FIRST(&kml->transaction_del);
+    u2 = QSIMPLEQ_FIRST(&kml->transaction_add);
+    while (u1 && u2) {
+        Range r1, r2;
+
+        range_init_nofail(&r1, u1->section.offset_within_address_space,
+                          int128_get64(u1->section.size));
+        range_init_nofail(&r2, u2->section.offset_within_address_space,
+                          int128_get64(u2->section.size));
+
+        if (range_overlaps_range(&r1, &r2)) {
+            need_inhibit = true;
+            break;
+        }
+        if (range_lob(&r1) < range_lob(&r2)) {
+            u1 = QSIMPLEQ_NEXT(u1, next);
+        } else {
+            u2 = QSIMPLEQ_NEXT(u2, next);
+        }
+    }
+
+    kvm_slots_lock();
+    if (need_inhibit) {
+        accel_ioctl_inhibit_begin();
+    }
+
+    /* Remove all memslots before adding the new ones. */
+    while (!QSIMPLEQ_EMPTY(&kml->transaction_del)) {
+        u1 = QSIMPLEQ_FIRST(&kml->transaction_del);
+        QSIMPLEQ_REMOVE_HEAD(&kml->transaction_del, next);
+
+        kvm_set_phys_mem(kml, &u1->section, false);
+        memory_region_unref(u1->section.mr);
+
+        g_free(u1);
+    }
+    while (!QSIMPLEQ_EMPTY(&kml->transaction_add)) {
+        u1 = QSIMPLEQ_FIRST(&kml->transaction_add);
+        QSIMPLEQ_REMOVE_HEAD(&kml->transaction_add, next);
+
+        memory_region_ref(u1->section.mr);
+        kvm_set_phys_mem(kml, &u1->section, true);
+
+        g_free(u1);
+    }
+
+    if (need_inhibit) {
+        accel_ioctl_inhibit_end();
+    }
+    kvm_slots_unlock();
 }
 
 static void kvm_log_sync(MemoryListener *listener,
@@ -1610,8 +1685,12 @@ void kvm_memory_listener_register(KVMState *s, KVMMemoryListener *kml,
         kml->slots[i].slot = i;
     }
 
+    QSIMPLEQ_INIT(&kml->transaction_add);
+    QSIMPLEQ_INIT(&kml->transaction_del);
+
     kml->listener.region_add = kvm_region_add;
     kml->listener.region_del = kvm_region_del;
+    kml->listener.commit = kvm_region_commit;
     kml->listener.log_start = kvm_log_start;
     kml->listener.log_stop = kvm_log_stop;
     kml->listener.priority = 10;
@@ -2310,6 +2389,7 @@ static int kvm_init(MachineState *ms)
     assert(TARGET_PAGE_SIZE <= qemu_real_host_page_size());
 
     s->sigmask_len = 8;
+    accel_blocker_init();
 
 #ifdef KVM_CAP_SET_GUEST_DEBUG
     QTAILQ_INIT(&s->kvm_sw_breakpoints);
@@ -3014,7 +3094,9 @@ int kvm_vm_ioctl(KVMState *s, int type, ...)
     va_end(ap);
 
     trace_kvm_vm_ioctl(type, arg);
+    accel_ioctl_begin();
     ret = ioctl(s->vmfd, type, arg);
+    accel_ioctl_end();
     if (ret == -1) {
         ret = -errno;
     }
@@ -3032,7 +3114,9 @@ int kvm_vcpu_ioctl(CPUState *cpu, int type, ...)
     va_end(ap);
 
     trace_kvm_vcpu_ioctl(cpu->cpu_index, type, arg);
+    accel_cpu_ioctl_begin(cpu);
     ret = ioctl(cpu->kvm_fd, type, arg);
+    accel_cpu_ioctl_end(cpu);
     if (ret == -1) {
         ret = -errno;
     }
@@ -3050,7 +3134,9 @@ int kvm_device_ioctl(int fd, int type, ...)
     va_end(ap);
 
     trace_kvm_device_ioctl(fd, type, arg);
+    accel_ioctl_begin();
     ret = ioctl(fd, type, arg);
+    accel_ioctl_end();
     if (ret == -1) {
         ret = -errno;
     }

accel/meson.build

@@ -1,4 +1,4 @@
-specific_ss.add(files('accel-common.c'))
+specific_ss.add(files('accel-common.c', 'accel-blocker.c'))
 softmmu_ss.add(files('accel-softmmu.c'))
 user_ss.add(files('accel-user.c'))
 

chardev/char-parallel.c

@@ -238,7 +238,6 @@ static void qemu_chr_open_pp_fd(Chardev *chr,
 }
 #endif
 
-#ifdef HAVE_CHARDEV_PARPORT
 static void qmp_chardev_open_parallel(Chardev *chr,
                                       ChardevBackend *backend,
                                       bool *be_opened,
@@ -276,29 +275,21 @@ static void char_parallel_class_init(ObjectClass *oc, void *data)
 
     cc->parse = qemu_chr_parse_parallel;
     cc->open = qmp_chardev_open_parallel;
-#if defined(__linux__)
     cc->chr_ioctl = pp_ioctl;
-#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || \
-    defined(__DragonFly__)
-    cc->chr_ioctl = pp_ioctl;
-#endif
 }
 
 static void char_parallel_finalize(Object *obj)
 {
-#if defined(__linux__)
     Chardev *chr = CHARDEV(obj);
     ParallelChardev *drv = PARALLEL_CHARDEV(chr);
     int fd = drv->fd;
 
+#if defined(__linux__)
     pp_hw_mode(drv, IEEE1284_MODE_COMPAT);
     ioctl(fd, PPRELEASE);
+#endif
     close(fd);
     qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
-#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || \
-    defined(__DragonFly__)
-    /* FIXME: close fd? */
-#endif
 }
 
 static const TypeInfo char_parallel_type_info = {
@@ -315,5 +306,3 @@ static void register_types(void)
 }
 
 type_init(register_types);
-
-#endif

chardev/meson.build

@@ -14,9 +14,12 @@ chardev_ss.add(files(
 ))
 chardev_ss.add(when: 'CONFIG_POSIX', if_true: [files(
   'char-fd.c',
-  'char-parallel.c',
   'char-pty.c',
 ), util])
+if targetos in ['linux', 'gnu/kfreebsd', 'freebsd', 'dragonfly']
+  chardev_ss.add(files('char-parallel.c'))
+endif
+
 chardev_ss.add(when: 'CONFIG_WIN32', if_true: files(
   'char-console.c',
   'char-win-stdio.c',

configure

@@ -1183,6 +1183,7 @@ add_to warn_flags -Wnested-externs
 add_to warn_flags -Wendif-labels
 add_to warn_flags -Wexpansion-to-defined
 add_to warn_flags -Wimplicit-fallthrough=2
+add_to warn_flags -Wmissing-format-attribute
 
 nowarn_flags=
 add_to nowarn_flags -Wno-initializer-overrides
@@ -2375,7 +2376,7 @@ echo "QEMU_OBJCFLAGS=$QEMU_OBJCFLAGS" >> $config_host_mak
 echo "GLIB_CFLAGS=$glib_cflags" >> $config_host_mak
 echo "GLIB_LIBS=$glib_libs" >> $config_host_mak
 echo "GLIB_BINDIR=$glib_bindir" >> $config_host_mak
-echo "GLIB_VERSION=$(pkg-config --modversion glib-2.0)" >> $config_host_mak
+echo "GLIB_VERSION=$($pkg_config --modversion glib-2.0)" >> $config_host_mak
 echo "QEMU_LDFLAGS=$QEMU_LDFLAGS" >> $config_host_mak
 echo "EXESUF=$EXESUF" >> $config_host_mak
 
@@ -2567,16 +2568,6 @@ if test "$skip_meson" = no; then
   if test "$?" -ne 0 ; then
       error_exit "meson setup failed"
   fi
-else
-  if test -f meson-private/cmd_line.txt; then
-    # Adjust old command line options whose type was changed
-    # Avoids having to use "setup --wipe" when Meson is upgraded
-    perl -i -ne '
-      s/^gettext = true$/gettext = auto/;
-      s/^gettext = false$/gettext = disabled/;
-      /^b_staticpic/ && next;
-      print;' meson-private/cmd_line.txt
-  fi
 fi
 
 # Save the configure command line for later reuse.

disas.c

@@ -239,7 +239,8 @@ void target_disas(FILE *out, CPUState *cpu, target_ulong code,
     }
 }
 
-static int gstring_printf(FILE *stream, const char *fmt, ...)
+static int G_GNUC_PRINTF(2, 3)
+gstring_printf(FILE *stream, const char *fmt, ...)
 {
     /* We abuse the FILE parameter to pass a GString. */
     GString *s = (GString *)stream;

hw/core/cpu-common.c

@@ -238,6 +238,7 @@ static void cpu_common_initfn(Object *obj)
     cpu->cflags_next_tb = -1;
 
     qemu_mutex_init(&cpu->work_mutex);
+    qemu_lockcnt_init(&cpu->in_ioctl_lock);
     QSIMPLEQ_INIT(&cpu->work_list);
     QTAILQ_INIT(&cpu->breakpoints);
     QTAILQ_INIT(&cpu->watchpoints);
@@ -249,6 +250,7 @@ static void cpu_common_finalize(Object *obj)
 {
     CPUState *cpu = CPU(obj);
 
+    qemu_lockcnt_destroy(&cpu->in_ioctl_lock);
     qemu_mutex_destroy(&cpu->work_mutex);
 }
 

hw/display/meson.build

@@ -73,10 +73,12 @@ if config_all_devices.has_key('CONFIG_VIRTIO_GPU')
   virtio_gpu_ss.add(when: 'CONFIG_VHOST_USER_GPU', if_true: files('vhost-user-gpu.c'))
   hw_display_modules += {'virtio-gpu': virtio_gpu_ss}
 
-  virtio_gpu_gl_ss = ss.source_set()
-  virtio_gpu_gl_ss.add(when: ['CONFIG_VIRTIO_GPU', virgl, opengl],
-                       if_true: [files('virtio-gpu-gl.c', 'virtio-gpu-virgl.c'), pixman, virgl])
-  hw_display_modules += {'virtio-gpu-gl': virtio_gpu_gl_ss}
+  if virgl.found() and opengl.found()
+    virtio_gpu_gl_ss = ss.source_set()
+    virtio_gpu_gl_ss.add(when: ['CONFIG_VIRTIO_GPU', virgl, opengl],
+                         if_true: [files('virtio-gpu-gl.c', 'virtio-gpu-virgl.c'), pixman, virgl])
+    hw_display_modules += {'virtio-gpu-gl': virtio_gpu_gl_ss}
+  endif
 endif
 
 if config_all_devices.has_key('CONFIG_VIRTIO_PCI')
@@ -87,10 +89,12 @@ if config_all_devices.has_key('CONFIG_VIRTIO_PCI')
                         if_true: files('vhost-user-gpu-pci.c'))
   hw_display_modules += {'virtio-gpu-pci': virtio_gpu_pci_ss}
 
-  virtio_gpu_pci_gl_ss = ss.source_set()
-  virtio_gpu_pci_gl_ss.add(when: ['CONFIG_VIRTIO_GPU', 'CONFIG_VIRTIO_PCI', virgl, opengl],
-                           if_true: [files('virtio-gpu-pci-gl.c'), pixman])
-  hw_display_modules += {'virtio-gpu-pci-gl': virtio_gpu_pci_gl_ss}
+  if virgl.found() and opengl.found()
+    virtio_gpu_pci_gl_ss = ss.source_set()
+    virtio_gpu_pci_gl_ss.add(when: ['CONFIG_VIRTIO_GPU', 'CONFIG_VIRTIO_PCI', virgl, opengl],
+                             if_true: [files('virtio-gpu-pci-gl.c'), pixman])
+    hw_display_modules += {'virtio-gpu-pci-gl': virtio_gpu_pci_gl_ss}
+  endif
 endif
 
 if config_all_devices.has_key('CONFIG_VIRTIO_VGA')

hw/xen/xen-bus.c

@@ -561,6 +561,7 @@ void xen_device_backend_printf(XenDevice *xendev, const char *key,
     }
 }
 
+G_GNUC_SCANF(3, 4)
 static int xen_device_backend_scanf(XenDevice *xendev, const char *key,
                                     const char *fmt, ...)
 {

hw/xen/xen_pvdev.c

@@ -196,6 +196,7 @@ const char *xenbus_strstate(enum xenbus_state state)
  *  2 == noisy debug messages (logfile only).
  *  3 == will flood your log (logfile only).
  */
+G_GNUC_PRINTF(3, 0)
 static void xen_pv_output_msg(struct XenLegacyDevice *xendev,
                               FILE *f, const char *fmt, va_list args)
 {

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);

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,

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);

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

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 */

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

subprojects/libvduse/libvduse.c

@@ -16,6 +16,10 @@
  * later.  See the COPYING file in the top-level directory.
  */
 
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
 #include <stdlib.h>
 #include <stdio.h>
 #include <stdbool.h>
@@ -97,7 +101,7 @@ struct VduseVirtq {
     uint16_t signalled_used;
     bool signalled_used_valid;
     int index;
-    int inuse;
+    unsigned int inuse;
     bool ready;
     int fd;
     VduseDev *dev;
@@ -578,7 +582,8 @@ void vduse_queue_notify(VduseVirtq *vq)
 
 static inline void vring_set_avail_event(VduseVirtq *vq, uint16_t val)
 {
-    *((uint16_t *)&vq->vring.used->ring[vq->vring.num]) = htole16(val);
+    uint16_t val_le = htole16(val);
+    memcpy(&vq->vring.used->ring[vq->vring.num], &val_le, sizeof(uint16_t));
 }
 
 static bool vduse_queue_map_single_desc(VduseVirtq *vq, unsigned int *p_num_sg,

subprojects/libvduse/meson.build

@@ -1,6 +1,12 @@
 project('libvduse', 'c',
         license: 'GPL-2.0-or-later',
-        default_options: ['c_std=gnu99'])
+        default_options: ['warning_level=1', 'c_std=gnu99'])
+
+cc = meson.get_compiler('c')
+add_project_arguments(cc.get_supported_arguments('-Wsign-compare',
+                                                 '-Wdeclaration-after-statement',
+                                                 '-Wstrict-aliasing'),
+                      native: false, language: 'c')
 
 libvduse = static_library('vduse',
                           files('libvduse.c'),