From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
---
include/migration/migration.h | 1 +
postcopy-ram.c | 93 +++++++++++++++++++++++++++++++++++++++++--
2 files changed, 90 insertions(+), 4 deletions(-)
diff --git a/include/migration/migration.h b/include/migration/migration.h
index 1a33b05..46fc37b 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -89,6 +89,7 @@ struct MigrationIncomingState {
QemuThread fault_thread;
QemuSemaphore fault_thread_sem;
+ int userfault_fd;
QEMUFile *return_path;
QemuMutex rp_mutex; /* We send replies from multiple threads */
diff --git a/postcopy-ram.c b/postcopy-ram.c
index de3534f..8d0a225 100644
--- a/postcopy-ram.c
+++ b/postcopy-ram.c
@@ -183,7 +183,6 @@ static void postcopy_pmi_dump(MigrationIncomingState *mis)
ram_debug_dump_bitmap(mis->postcopy_pmi.received_map, true);
}
-/* ---------------------------------------------------------------------- */
int postcopy_ram_hosttest(void)
{
/* TODO: Needs guarding with CONFIG_ once we have libc's that have the defs
@@ -367,12 +366,97 @@ static int postcopy_ram_sensitise_area(const char
*block_name, void *host_addr,
static void *postcopy_ram_fault_thread(void *opaque)
{
MigrationIncomingState *mis = (MigrationIncomingState *)opaque;
+ void *hostaddr;
+ int ret;
+ size_t hostpagesize = getpagesize();
+ RAMBlock *rb = NULL;
+ RAMBlock *last_rb = NULL;
- fprintf(stderr, "postcopy_ram_fault_thread\n");
- /* TODO: In later patch */
+ DPRINTF("%s", __func__);
qemu_sem_post(&mis->fault_thread_sem);
while (1) {
- /* TODO: In later patch */
+ PostcopyPMIState old_state, tmp_state;
+ ram_addr_t rb_offset;
+ ram_addr_t in_raspace;
+ unsigned long bitmap_index;
+
+ /* Read a faulting HVA from the kernel */
+ ret = read(mis->userfault_fd, &hostaddr, sizeof(hostaddr));
+ if (ret != sizeof(hostaddr)) {
+ if (ret < 0) {
+ perror("Failed to read full userfault hostaddr");
+ break;
+ } else {
+ error_report("%s: Read %d bytes from userfaultfd expected %ld",
+ __func__, ret, sizeof(hostaddr));
+ break; /* Lost alignment, don't know what we'd read next */
+ }
+ }
+
+ /* TODO: We want to be marking host-page-size areas of the bitmaps? */
+ last_rb = rb;
+ rb = qemu_ram_block_from_host(hostaddr, &in_raspace, &rb_offset,
+ &bitmap_index);
+ if (!rb) {
+ error_report("postcopy_ram_fault_thread: Fault outside guest: %p",
+ hostaddr);
+ break;
+ }
+
+ DPRINTF("%s: Request for HVA=%p index=%lx rb=%s offset=%zx",
+ __func__, hostaddr, bitmap_index, qemu_ram_get_idstr(rb),
+ rb_offset);
+
+ tmp_state = postcopy_pmi_get_state(mis, bitmap_index);
+ do {
+ old_state = tmp_state;
+
+ switch (old_state) {
+ case POSTCOPY_PMI_REQUESTED:
+ /* Do nothing - it's already requested */
+ break;
+
+ case POSTCOPY_PMI_RECEIVED:
+ /* Already arrived - no state change, just kick the kernel */
+ DPRINTF("postcopy_ram_fault_thread: notify pre of %p",
+ hostaddr);
+ /* TODO! Send ack
+ if (ack_userfault(mis, hostaddr, hostpagesize)) {
+ assert(0);
+ } */
+ break;
+
+ case POSTCOPY_PMI_MISSING:
+
+ tmp_state = postcopy_pmi_change_state(mis, bitmap_index,
+ old_state, POSTCOPY_PMI_REQUESTED);
+ if (tmp_state == POSTCOPY_PMI_MISSING) {
+ /*
+ * Send the request to the source - we want to request one
+ * of our host page sizes (which is >= TPS)
+ */
+ if (rb != last_rb) {
+ migrate_send_rp_reqpages(mis, qemu_ram_get_idstr(rb),
+ rb_offset, hostpagesize);
+ } else {
+ /* Save some space */
+ migrate_send_rp_reqpages(mis, NULL,
+ rb_offset, hostpagesize);
+ }
+
+ if (mis->postcopy_ram_state == POSTCOPY_RAM_INCOMING_END) {
+ /* This shouldn't happen - the command to close the
+ * postcopy stream should be after the last page of RAM
+ * so we're not going to get an answer
+ */
+ error_report("postcopy_ram_fault_thread: UF after
end");
+ postcopy_pmi_dump(mis);
+ assert(0);
+ }
+ }
+ break;
+ }
+ } while (tmp_state != old_state);
}
return NULL;
@@ -381,6 +465,7 @@ static void *postcopy_ram_fault_thread(void *opaque)
int postcopy_ram_enable_notify(MigrationIncomingState *mis)
{
/* Create the fault handler thread and wait for it to be ready */
+ mis->userfault_fd = -1; /* TODO */
qemu_sem_init(&mis->fault_thread_sem, 0);
qemu_thread_create(&mis->fault_thread, "postcopy/fault",
postcopy_ram_fault_thread, mis, QEMU_THREAD_JOINABLE);
--
1.9.3
