hw/cxl: Introduce cxl_device_get_timestamp() utility function

There are new users of this functionality coming shortly so factor
it out from the GET_TIMESTAMP mailbox command handling.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Fan Ni <fan.ni@samsung.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Message-Id: <20230423162013.4535-3-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/hw/cxl/cxl-device-utils.c b/hw/cxl/cxl-device-utils.c
index 4c5e88aaf5..86e1cea8ce 100644
--- a/hw/cxl/cxl-device-utils.c
+++ b/hw/cxl/cxl-device-utils.c
@@ -269,3 +269,18 @@ void cxl_device_register_init_common(CXLDeviceState *cxl_dstate)
 
     cxl_initialize_mailbox(cxl_dstate);
 }
+
+uint64_t cxl_device_get_timestamp(CXLDeviceState *cxl_dstate)
+{
+    uint64_t time, delta;
+    uint64_t final_time = 0;
+
+    if (cxl_dstate->timestamp.set) {
+        /* Find the delta from the last time the host set the time. */
+        time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+        delta = time - cxl_dstate->timestamp.last_set;
+        final_time = cxl_dstate->timestamp.host_set + delta;
+    }
+
+    return final_time;
+}