[Qemu-devel] [PATCH 3/6] migration: add UFFD_FEATURE_THREAD_ID feature support

[Alexey Perevalov]

Userfaultfd mechanism is able to provide process thread id,
in case when client request it with UFDD_API ioctl.

Signed-off-by: Alexey Perevalov <address@hidden>
---
 include/migration/postcopy-ram.h |  2 +-
 migration/migration.c            |  2 +-
 migration/postcopy-ram.c         | 12 ++++++------
 migration/savevm.c               |  2 +-
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/include/migration/postcopy-ram.h b/include/migration/postcopy-ram.h
index 8e036b9..809f6db 100644
--- a/include/migration/postcopy-ram.h
+++ b/include/migration/postcopy-ram.h
@@ -14,7 +14,7 @@
 #define QEMU_POSTCOPY_RAM_H
 
 /* Return true if the host supports everything we need to do postcopy-ram */
-bool postcopy_ram_supported_by_host(void);
+bool postcopy_ram_supported_by_host(MigrationIncomingState *mis);
 
 /*
  * Make all of RAM sensitive to accesses to areas that haven't yet been written
diff --git a/migration/migration.c b/migration/migration.c
index ad4036f..79f6425 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -802,7 +802,7 @@ void 
qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
          * special support.
          */
         if (!old_postcopy_cap && runstate_check(RUN_STATE_INMIGRATE) &&
-            !postcopy_ram_supported_by_host()) {
+            !postcopy_ram_supported_by_host(NULL)) {
             /* postcopy_ram_supported_by_host will have emitted a more
              * detailed message
              */
diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
index dc80dbb..70f0480 100644
--- a/migration/postcopy-ram.c
+++ b/migration/postcopy-ram.c
@@ -60,13 +60,13 @@ struct PostcopyDiscardState {
 #include <sys/eventfd.h>
 #include <linux/userfaultfd.h>
 
-static bool ufd_version_check(int ufd)
+static bool ufd_version_check(int ufd, MigrationIncomingState *mis)
 {
     struct uffdio_api api_struct;
     uint64_t ioctl_mask;
 
     api_struct.api = UFFD_API;
-    api_struct.features = 0;
+    api_struct.features = UFFD_FEATURE_THREAD_ID;
     if (ioctl(ufd, UFFDIO_API, &api_struct)) {
         error_report("postcopy_ram_supported_by_host: UFFDIO_API failed: %s",
                      strerror(errno));
@@ -113,7 +113,7 @@ static int test_range_shared(const char *block_name, void 
*host_addr,
  * normally fine since if the postcopy succeeds it gets turned back on at the
  * end.
  */
-bool postcopy_ram_supported_by_host(void)
+bool postcopy_ram_supported_by_host(MigrationIncomingState *mis)
 {
     long pagesize = getpagesize();
     int ufd = -1;
@@ -136,7 +136,7 @@ bool postcopy_ram_supported_by_host(void)
     }
 
     /* Version and features check */
-    if (!ufd_version_check(ufd)) {
+    if (!ufd_version_check(ufd, mis)) {
         goto out;
     }
 
@@ -515,7 +515,7 @@ int postcopy_ram_enable_notify(MigrationIncomingState *mis)
      * Although the host check already tested the API, we need to
      * do the check again as an ABI handshake on the new fd.
      */
-    if (!ufd_version_check(mis->userfault_fd)) {
+    if (!ufd_version_check(mis->userfault_fd, mis)) {
         return -1;
     }
 
@@ -653,7 +653,7 @@ void *postcopy_get_tmp_page(MigrationIncomingState *mis)
 
 #else
 /* No target OS support, stubs just fail */
-bool postcopy_ram_supported_by_host(void)
+bool postcopy_ram_supported_by_host(MigrationIncomingState *mis)
 {
     error_report("%s: No OS support", __func__);
     return false;
diff --git a/migration/savevm.c b/migration/savevm.c
index 3b19a4a..f01e418 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1360,7 +1360,7 @@ static int 
loadvm_postcopy_handle_advise(MigrationIncomingState *mis)
         return -1;
     }
 
-    if (!postcopy_ram_supported_by_host()) {
+    if (!postcopy_ram_supported_by_host(mis)) {
         postcopy_state_set(POSTCOPY_INCOMING_NONE);
         return -1;
     }
-- 
1.8.3.1