On Tue, Jun 10, 2025 at 10:26:43AM -0700, Steve Sistare wrote:
> Do not reset a vfio-pci device during CPR.
>
> Signed-off-by: Steve Sistare
Acked-by: Michael S. Tsirkin
> ---
> hw/pci/pci.c | 5 +
> hw/vfio/pci.c| 7 +++
> include/hw/pci/pci.h | 2 ++
> 3 files changed, 14 insertions(+)
>
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index 9b4bf48..c70b5ce 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->cap_present & QEMU_PCI_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..4cd92c3 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->cap_present |= QEMU_PCI_SKIP_RESET_ON_CPR;
> }
>
> static void vfio_pci_base_dev_class_init(ObjectClass *klass, const void
> *data)
> diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
> index 35d59d7..df3cc7b 100644
> --- a/include/hw/pci/pci.h
> +++ b/include/hw/pci/pci.h
> @@ -222,6 +222,8 @@ enum {
> QEMU_PCIE_EXT_TAG = (1 << QEMU_PCIE_EXT_TAG_BITNR),
> #define QEMU_PCI_CAP_PM_BITNR 14
> QEMU_PCI_CAP_PM = (1 << QEMU_PCI_CAP_PM_BITNR),
> +#define QEMU_PCI_SKIP_RESET_ON_CPR_BITNR 15
> +QEMU_PCI_SKIP_RESET_ON_CPR = (1 << QEMU_PCI_SKIP_RESET_ON_CPR_BITNR),
> };
>
> typedef struct PCIINTxRoute {
> --
> 1.8.3.1
