Re: [PATCH V3 02/42] migration: cpr helpers

[Cédric Le Goater]

On 5/12/25 17:32, Steve Sistare wrote:

Add the cpr_needed_for_reuse and cpr_open_fd, for use when adding cpr
support for vfio and iommufd.

Signed-off-by: Steve Sistare <steven.sist...@oracle.com>

Reviewed-by: Cédric Le Goater <c...@redhat.com>

Thanks,

C.

---
  include/migration/cpr.h |  4 ++++
  migration/cpr.c         | 24 ++++++++++++++++++++++++
  2 files changed, 28 insertions(+)

diff --git a/include/migration/cpr.h b/include/migration/cpr.h
index 7561fc7..fc6aa33 100644
--- a/include/migration/cpr.h
+++ b/include/migration/cpr.h
@@ -18,6 +18,8 @@
  void cpr_save_fd(const char *name, int id, int fd);
  void cpr_delete_fd(const char *name, int id);
  int cpr_find_fd(const char *name, int id);
+int cpr_open_fd(const char *path, int flags, const char *name, int id,
+                bool *reused, Error **errp);

MigMode cpr_get_incoming_mode(void);

  void cpr_set_incoming_mode(MigMode mode);
@@ -28,6 +30,8 @@ int cpr_state_load(MigrationChannel *channel, Error **errp);
  void cpr_state_close(void);
  struct QIOChannel *cpr_state_ioc(void);

+bool cpr_needed_for_reuse(void *opaque);

+
  QEMUFile *cpr_transfer_output(MigrationChannel *channel, Error **errp);
  QEMUFile *cpr_transfer_input(MigrationChannel *channel, Error **errp);

diff --git a/migration/cpr.c b/migration/cpr.c

index 42c4656..0b01e25 100644
--- a/migration/cpr.c
+++ b/migration/cpr.c
@@ -95,6 +95,24 @@ int cpr_find_fd(const char *name, int id)
      trace_cpr_find_fd(name, id, fd);
      return fd;
  }
+
+int cpr_open_fd(const char *path, int flags, const char *name, int id,
+                bool *reused, Error **errp)
+{
+    int fd = cpr_find_fd(name, id);
+
+    if (reused) {
+        *reused = (fd >= 0);
+    }
+    if (fd < 0) {
+        fd = qemu_open(path, flags, errp);
+        if (fd >= 0) {
+            cpr_save_fd(name, id, fd);
+        }
+    }
+    return fd;
+}
+
  /*************************************************************************/
  #define CPR_STATE "CprState"

@@ -228,3 +246,9 @@ void cpr_state_close(void)

          cpr_state_file = NULL;
      }
  }
+
+bool cpr_needed_for_reuse(void *opaque)
+{
+    MigMode mode = migrate_mode();
+    return mode == MIG_MODE_CPR_TRANSFER;
+}