| Message ID | 1434450415-11339-28-git-send-email-dgilbert@redhat.com |
|---|---|
| State | New |
| Headers | show |
"Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote: > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > > Mark the area of RAM as 'userfault' > Start up a fault-thread to handle any userfaults we might receive > from it (to be filled in later) > > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > Reviewed-by: David Gibson <david@gibson.dropbear.id.au> > --- > include/migration/migration.h | 3 ++ > include/migration/postcopy-ram.h | 6 ++++ > migration/postcopy-ram.c | 69 +++++++++++++++++++++++++++++++++++++++- > migration/savevm.c | 9 ++++++ > 4 files changed, 86 insertions(+), 1 deletion(-) > > diff --git a/include/migration/migration.h b/include/migration/migration.h > index 98e2568..e6585c5 100644 > --- a/include/migration/migration.h > +++ b/include/migration/migration.h > @@ -69,6 +69,9 @@ struct MigrationIncomingState { > */ > QemuEvent main_thread_load_event; > > + QemuThread fault_thread; Best name ever? Well, it could be "wrong_thread" O:-) > +static void *postcopy_ram_fault_thread(void *opaque) > +{ > + MigrationIncomingState *mis = (MigrationIncomingState *)opaque; Uneeded cast. > + > + fprintf(stderr, "postcopy_ram_fault_thread\n"); > + /* TODO: In later patch */ > + qemu_sem_post(&mis->fault_thread_sem); > + while (1) { > + /* TODO: In later patch */ > + } > + > + return NULL; > +} > + > +int postcopy_ram_enable_notify(MigrationIncomingState *mis) > +{ > + /* Create the fault handler thread and wait for it to be ready */ > + qemu_sem_init(&mis->fault_thread_sem, 0); > + qemu_thread_create(&mis->fault_thread, "postcopy/fault", > + postcopy_ram_fault_thread, mis, QEMU_THREAD_JOINABLE); > + qemu_sem_wait(&mis->fault_thread_sem); > + qemu_sem_destroy(&mis->fault_thread_sem); > + > + /* Mark so that we get notified of accesses to unwritten areas */ > + if (qemu_ram_foreach_block(ram_block_enable_notify, mis)) { > + return -1; > + } > + > + return 0; > +} > + > #else > /* No target OS support, stubs just fail */ > - This belongs in a different patch O:-) If you have to resend, just change them. Reviewed-by: Juan Quintela <quintela@redhat.com>
* Juan Quintela (quintela@redhat.com) wrote: > "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote: > > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > > > > Mark the area of RAM as 'userfault' > > Start up a fault-thread to handle any userfaults we might receive > > from it (to be filled in later) > > > > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > > Reviewed-by: David Gibson <david@gibson.dropbear.id.au> > > --- > > include/migration/migration.h | 3 ++ > > include/migration/postcopy-ram.h | 6 ++++ > > migration/postcopy-ram.c | 69 +++++++++++++++++++++++++++++++++++++++- > > migration/savevm.c | 9 ++++++ > > 4 files changed, 86 insertions(+), 1 deletion(-) > > > > diff --git a/include/migration/migration.h b/include/migration/migration.h > > index 98e2568..e6585c5 100644 > > --- a/include/migration/migration.h > > +++ b/include/migration/migration.h > > @@ -69,6 +69,9 @@ struct MigrationIncomingState { > > */ > > QemuEvent main_thread_load_event; > > > > + QemuThread fault_thread; > > Best name ever? Well, it could be "wrong_thread" O:-) Well they are 'user faults'! Not that we blame the user for them personally of course. > > +static void *postcopy_ram_fault_thread(void *opaque) > > +{ > > + MigrationIncomingState *mis = (MigrationIncomingState *)opaque; > > Uneeded cast. Thanks, gone. > > + > > + fprintf(stderr, "postcopy_ram_fault_thread\n"); > > + /* TODO: In later patch */ > > + qemu_sem_post(&mis->fault_thread_sem); > > + while (1) { > > + /* TODO: In later patch */ > > + } > > + > > + return NULL; > > +} > > + > > +int postcopy_ram_enable_notify(MigrationIncomingState *mis) > > +{ > > + /* Create the fault handler thread and wait for it to be ready */ > > + qemu_sem_init(&mis->fault_thread_sem, 0); > > + qemu_thread_create(&mis->fault_thread, "postcopy/fault", > > + postcopy_ram_fault_thread, mis, QEMU_THREAD_JOINABLE); > > + qemu_sem_wait(&mis->fault_thread_sem); > > + qemu_sem_destroy(&mis->fault_thread_sem); > > + > > + /* Mark so that we get notified of accesses to unwritten areas */ > > + if (qemu_ram_foreach_block(ram_block_enable_notify, mis)) { > > + return -1; > > + } > > + > > + return 0; > > +} > > + > > #else > > /* No target OS support, stubs just fail */ > > - > > This belongs in a different patch O:-) Thanks, gone. > If you have to resend, just change them. > > Reviewed-by: Juan Quintela <quintela@redhat.com> Dave -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
On (Tue) 16 Jun 2015 [11:26:40], Dr. David Alan Gilbert (git) wrote: > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > > Mark the area of RAM as 'userfault' > Start up a fault-thread to handle any userfaults we might receive > from it (to be filled in later) > > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Reviewed-by: Amit Shah <amit.shah@redhat.com> Amit
diff --git a/include/migration/migration.h b/include/migration/migration.h index 98e2568..e6585c5 100644 --- a/include/migration/migration.h +++ b/include/migration/migration.h @@ -69,6 +69,9 @@ struct MigrationIncomingState { */ QemuEvent main_thread_load_event; + QemuThread fault_thread; + QemuSemaphore fault_thread_sem; + /* For the kernel to send us notifications */ int userfault_fd; QEMUFile *return_path; diff --git a/include/migration/postcopy-ram.h b/include/migration/postcopy-ram.h index 4192108..8a8616b 100644 --- a/include/migration/postcopy-ram.h +++ b/include/migration/postcopy-ram.h @@ -17,6 +17,12 @@ bool postcopy_ram_supported_by_host(void); /* + * Make all of RAM sensitive to accesses to areas that haven't yet been written + * and wire up anything necessary to deal with it. + */ +int postcopy_ram_enable_notify(MigrationIncomingState *mis); + +/* * Initialise postcopy-ram, setting the RAM to a state where we can go into * postcopy later; must be called prior to any precopy. * called from ram.c's similarly named ram_postcopy_incoming_init diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c index 35c87b4..7158d08 100644 --- a/migration/postcopy-ram.c +++ b/migration/postcopy-ram.c @@ -282,9 +282,71 @@ int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis) return 0; } +/* + * Mark the given area of RAM as requiring notification to unwritten areas + * Used as a callback on qemu_ram_foreach_block. + * host_addr: Base of area to mark + * offset: Offset in the whole ram arena + * length: Length of the section + * opaque: MigrationIncomingState pointer + * Returns 0 on success + */ +static int ram_block_enable_notify(const char *block_name, void *host_addr, + ram_addr_t offset, ram_addr_t length, + void *opaque) +{ + MigrationIncomingState *mis = opaque; + struct uffdio_register reg_struct; + + reg_struct.range.start = (uintptr_t)host_addr; + reg_struct.range.len = length; + reg_struct.mode = UFFDIO_REGISTER_MODE_MISSING; + + /* Now tell our userfault_fd that it's responsible for this area */ + if (ioctl(mis->userfault_fd, UFFDIO_REGISTER, ®_struct)) { + error_report("%s userfault register: %s", __func__, strerror(errno)); + return -1; + } + + return 0; +} + +/* + * Handle faults detected by the USERFAULT markings + */ +static void *postcopy_ram_fault_thread(void *opaque) +{ + MigrationIncomingState *mis = (MigrationIncomingState *)opaque; + + fprintf(stderr, "postcopy_ram_fault_thread\n"); + /* TODO: In later patch */ + qemu_sem_post(&mis->fault_thread_sem); + while (1) { + /* TODO: In later patch */ + } + + return NULL; +} + +int postcopy_ram_enable_notify(MigrationIncomingState *mis) +{ + /* Create the fault handler thread and wait for it to be ready */ + qemu_sem_init(&mis->fault_thread_sem, 0); + qemu_thread_create(&mis->fault_thread, "postcopy/fault", + postcopy_ram_fault_thread, mis, QEMU_THREAD_JOINABLE); + qemu_sem_wait(&mis->fault_thread_sem); + qemu_sem_destroy(&mis->fault_thread_sem); + + /* Mark so that we get notified of accesses to unwritten areas */ + if (qemu_ram_foreach_block(ram_block_enable_notify, mis)) { + return -1; + } + + return 0; +} + #else /* No target OS support, stubs just fail */ - bool postcopy_ram_supported_by_host(void) { error_report("%s: No OS support", __func__); @@ -307,6 +369,11 @@ int postcopy_ram_discard_range(MigrationIncomingState *mis, uint8_t *start, { assert(0); } + +int postcopy_ram_enable_notify(MigrationIncomingState *mis) +{ + assert(0); +} #endif /* ------------------------------------------------------------------------- */ diff --git a/migration/savevm.c b/migration/savevm.c index f4de52d..b87238a 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -1324,6 +1324,15 @@ static int loadvm_postcopy_handle_listen(MigrationIncomingState *mis) return -1; } + /* + * Sensitise RAM - can now generate requests for blocks that don't exist + * However, at this point the CPU shouldn't be running, and the IO + * shouldn't be doing anything yet so don't actually expect requests + */ + if (postcopy_ram_enable_notify(mis)) { + return -1; + } + /* TODO start up the postcopy listening thread */ return 0; }