[PATCH V5 10/38] pci: skip reset during cpr

[Steve Sistare <steven.sistare@oracle.com>]

Do not reset a vfio-pci device during CPR.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 include/hw/pci/pci_device.h | 3 +++
 hw/pci/pci.c                | 5 +++++
 hw/vfio/pci.c               | 7 +++++++
 3 files changed, 15 insertions(+)

diff --git a/include/hw/pci/pci_device.h b/include/hw/pci/pci_device.h
index eee0338..0509430 100644
--- a/include/hw/pci/pci_device.h
+++ b/include/hw/pci/pci_device.h
@@ -182,6 +182,9 @@ struct PCIDevice {
     uint32_t max_bounce_buffer_size;
 
     char *sriov_pf;
+
+    /* CPR */
+    bool skip_reset_on_cpr;
 };
 
 static inline int pci_intx(PCIDevice *pci_dev)
diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 9b4bf48..0f6b9b3 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -32,6 +32,7 @@
 #include "hw/pci/pci_host.h"
 #include "hw/qdev-properties.h"
 #include "hw/qdev-properties-system.h"
+#include "migration/cpr.h"
 #include "migration/qemu-file-types.h"
 #include "migration/vmstate.h"
 #include "net/net.h"
@@ -537,6 +538,10 @@ static void pci_reset_regions(PCIDevice *dev)
 
 static void pci_do_device_reset(PCIDevice *dev)
 {
+    if (dev->skip_reset_on_cpr && cpr_is_incoming()) {
+        return;
+    }
+
     pci_device_deassert_intx(dev);
     assert(dev->irq_state == 0);
 
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index b1250d8..819170d 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -3408,6 +3408,13 @@ static void vfio_instance_init(Object *obj)
     /* QEMU_PCI_CAP_EXPRESS initialization does not depend on QEMU command
      * line, therefore, no need to wait to realize like other devices */
     pci_dev->cap_present |= QEMU_PCI_CAP_EXPRESS;
+
+    /*
+     * A device that is resuming for cpr is already configured, so do not
+     * reset it during qemu_system_reset prior to cpr load, else interrupts
+     * may be lost.
+     */
+    pci_dev->skip_reset_on_cpr = true;
 }
 
 static void vfio_pci_base_dev_class_init(ObjectClass *klass, const void *data)
-- 
1.8.3.1