Fix for object_del of in-use memory, pvpanic

regression, PPC regression and bogus error message with
 Oxygen theme.
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Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging

Fix for object_del of in-use memory, pvpanic
regression, PPC regression and bogus error message with
Oxygen theme.

# gpg: Signature made Wed Apr  1 09:08:20 2015 BST using RSA key ID 78C7AE83
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>"
# gpg:                 aka "Paolo Bonzini <pbonzini@redhat.com>"
# gpg: WARNING: This key is not certified with sufficiently trusted signatures!
# gpg:          It is not certain that the signature belongs to the owner.
# 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

* remotes/bonzini/tags/for-upstream:
  Revert "exec: Respect as_tranlsate_internal length clamp"
  rcu: do not create thread in pthread_atfork callback
  pc: acpi: fix pvpanic regression
  hostmem: Prevent removing an in-use memory backend
  qom: Add can_be_deleted callback to UserCreatableClass

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

backends/hostmem.c

@@ -335,12 +335,26 @@ host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
     }
 }
 
+static bool
+host_memory_backend_can_be_deleted(UserCreatable *uc, Error **errp)
+{
+    MemoryRegion *mr;
+
+    mr = host_memory_backend_get_memory(MEMORY_BACKEND(uc), errp);
+    if (memory_region_is_mapped(mr)) {
+        return false;
+    } else {
+        return true;
+    }
+}
+
 static void
 host_memory_backend_class_init(ObjectClass *oc, void *data)
 {
     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
 
     ucc->complete = host_memory_backend_memory_complete;
+    ucc->can_be_deleted = host_memory_backend_can_be_deleted;
 }
 
 static const TypeInfo host_memory_backend_info = {

exec.c

@@ -380,6 +380,7 @@ MemoryRegion *address_space_translate(AddressSpace *as, hwaddr addr,
     IOMMUTLBEntry iotlb;
     MemoryRegionSection *section;
     MemoryRegion *mr;
+    hwaddr len = *plen;
 
     rcu_read_lock();
     for (;;) {
@@ -394,7 +395,7 @@ MemoryRegion *address_space_translate(AddressSpace *as, hwaddr addr,
         iotlb = mr->iommu_ops->translate(mr, addr, is_write);
         addr = ((iotlb.translated_addr & ~iotlb.addr_mask)
                 | (addr & iotlb.addr_mask));
-        *plen = MIN(*plen, (addr | iotlb.addr_mask) - addr + 1);
+        len = MIN(len, (addr | iotlb.addr_mask) - addr + 1);
         if (!(iotlb.perm & (1 << is_write))) {
             mr = &io_mem_unassigned;
             break;
@@ -405,9 +406,10 @@ MemoryRegion *address_space_translate(AddressSpace *as, hwaddr addr,
 
     if (xen_enabled() && memory_access_is_direct(mr, is_write)) {
         hwaddr page = ((addr & TARGET_PAGE_MASK) + TARGET_PAGE_SIZE) - addr;
-        *plen = MIN(page, *plen);
+        len = MIN(page, len);
     }
 
+    *plen = len;
     *xlat = addr;
     rcu_read_unlock();
     return mr;

hw/i386/acpi-build.c

@@ -788,7 +788,7 @@ build_ssdt(GArray *table_data, GArray *linker,
         scope = aml_scope("\\_SB.PCI0.ISA");
 
         dev = aml_device("PEVR");
-        aml_append(dev, aml_name_decl("_HID", aml_string("QEMU0002")));
+        aml_append(dev, aml_name_decl("_HID", aml_string("QEMU0001")));
 
         crs = aml_resource_template();
         aml_append(crs,

include/qemu/rcu.h

@@ -117,6 +117,7 @@ extern void synchronize_rcu(void);
  */
 extern void rcu_register_thread(void);
 extern void rcu_unregister_thread(void);
+extern void rcu_after_fork(void);
 
 struct rcu_head;
 typedef void RCUCBFunc(struct rcu_head *head);

include/qom/object_interfaces.h

@@ -25,6 +25,8 @@ typedef struct UserCreatable {
  * UserCreatableClass:
  * @parent_class: the base class
  * @complete: callback to be called after @obj's properties are set.
+ * @can_be_deleted: callback to be called before an object is removed
+ * to check if @obj can be removed safely.
  *
  * Interface is designed to work with -object/object-add/object_add
  * commands.
@@ -47,6 +49,7 @@ typedef struct UserCreatableClass {
 
     /* <public> */
     void (*complete)(UserCreatable *uc, Error **errp);
+    bool (*can_be_deleted)(UserCreatable *uc, Error **errp);
 } UserCreatableClass;
 
 /**
@@ -59,4 +62,14 @@ typedef struct UserCreatableClass {
  * nothing.
  */
 void user_creatable_complete(Object *obj, Error **errp);
+
+/**
+ * user_creatable_can_be_deleted:
+ * @uc: the object whose can_be_deleted() method is called if implemented
+ * @errp: if an error occurs, a pointer to an area to store the error
+ *
+ * Wrapper to call can_be_deleted() method if one of types it's inherited
+ * from implements USER_CREATABLE interface.
+ */
+bool user_creatable_can_be_deleted(UserCreatable *uc, Error **errp);
 #endif

linux-user/syscall.c

@@ -4572,6 +4572,7 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp,
         ret = fork();
         if (ret == 0) {
             /* Child Process.  */
+            rcu_after_fork();
             cpu_clone_regs(env, newsp);
             fork_end(1);
             /* There is a race condition here.  The parent process could

os-posix.c

@@ -39,6 +39,7 @@
 #include "sysemu/sysemu.h"
 #include "net/slirp.h"
 #include "qemu-options.h"
+#include "qemu/rcu.h"
 
 #ifdef CONFIG_LINUX
 #include <sys/prctl.h>
@@ -247,6 +248,7 @@ void os_daemonize(void)
         signal(SIGTSTP, SIG_IGN);
         signal(SIGTTOU, SIG_IGN);
         signal(SIGTTIN, SIG_IGN);
+        rcu_after_fork();
     }
 }
 

qmp.c

@@ -711,6 +711,11 @@ void qmp_object_del(const char *id, Error **errp)
         error_setg(errp, "object id not found");
         return;
     }
+
+    if (!user_creatable_can_be_deleted(USER_CREATABLE(obj), errp)) {
+        error_setg(errp, "%s is in use, can not be deleted", id);
+        return;
+    }
     object_unparent(obj);
 }
 

qom/object_interfaces.c

@@ -18,6 +18,18 @@ void user_creatable_complete(Object *obj, Error **errp)
     }
 }
 
+bool user_creatable_can_be_deleted(UserCreatable *uc, Error **errp)
+{
+
+    UserCreatableClass *ucc = USER_CREATABLE_GET_CLASS(uc);
+
+    if (ucc->can_be_deleted) {
+        return ucc->can_be_deleted(uc, errp);
+    } else {
+        return true;
+    }
+}
+
 static void register_types(void)
 {
     static const TypeInfo uc_interface_info = {

util/rcu.c

@@ -311,19 +311,18 @@ static void rcu_init_unlock(void)
 {
     qemu_mutex_unlock(&rcu_gp_lock);
 }
+#endif
 
-static void rcu_init_child(void)
+void rcu_after_fork(void)
 {
-    qemu_mutex_unlock(&rcu_gp_lock);
     memset(&registry, 0, sizeof(registry));
     rcu_init_complete();
 }
-#endif
 
 static void __attribute__((__constructor__)) rcu_init(void)
 {
 #ifdef CONFIG_POSIX
-    pthread_atfork(rcu_init_lock, rcu_init_unlock, rcu_init_child);
+    pthread_atfork(rcu_init_lock, rcu_init_unlock, rcu_init_unlock);
 #endif
     rcu_init_complete();
 }