vfio/qat: Add vfio_pci driver for Intel QAT SR-IOV VF devices

Add vfio pci variant driver for Intel QAT SR-IOV VF devices. This driver
registers to the vfio subsystem through the interfaces exposed by the
subsystem. It follows the live migration protocol v2 defined in
uapi/linux/vfio.h and interacts with Intel QAT PF driver through a set
of interfaces defined in qat/qat_mig_dev.h to support live migration of
Intel QAT VF devices.

This version only covers migration for Intel QAT GEN4 VF devices.

Co-developed-by: Yahui Cao <yahui.cao@intel.com>
Signed-off-by: Yahui Cao <yahui.cao@intel.com>
Signed-off-by: Xin Zeng <xin.zeng@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20240426064051.2859652-1-xin.zeng@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

MAINTAINERS

@@ -23280,6 +23280,14 @@ L:	kvm@vger.kernel.org
 S:	Maintained
 F:	drivers/vfio/platform/
 
+VFIO QAT PCI DRIVER
+M:	Xin Zeng <xin.zeng@intel.com>
+M:	Giovanni Cabiddu <giovanni.cabiddu@intel.com>
+L:	kvm@vger.kernel.org
+L:	qat-linux@intel.com
+S:	Supported
+F:	drivers/vfio/pci/qat/
+
 VFIO VIRTIO PCI DRIVER
 M:	Yishai Hadas <yishaih@nvidia.com>
 L:	kvm@vger.kernel.org

drivers/vfio/pci/Kconfig

@@ -69,4 +69,6 @@ source "drivers/vfio/pci/virtio/Kconfig"
 
 source "drivers/vfio/pci/nvgrace-gpu/Kconfig"
 
+source "drivers/vfio/pci/qat/Kconfig"
+
 endmenu

drivers/vfio/pci/Makefile

@@ -17,3 +17,5 @@ obj-$(CONFIG_PDS_VFIO_PCI) += pds/
 obj-$(CONFIG_VIRTIO_VFIO_PCI) += virtio/
 
 obj-$(CONFIG_NVGRACE_GPU_VFIO_PCI) += nvgrace-gpu/
+
+obj-$(CONFIG_QAT_VFIO_PCI) += qat/

drivers/vfio/pci/qat/Kconfig

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config QAT_VFIO_PCI
+	tristate "VFIO support for QAT VF PCI devices"
+	select VFIO_PCI_CORE
+	depends on CRYPTO_DEV_QAT_4XXX
+	help
+	  This provides migration support for Intel(R) QAT Virtual Function
+	  using the VFIO framework.
+
+	  To compile this as a module, choose M here: the module
+	  will be called qat_vfio_pci. If you don't know what to do here,
+	  say N.

drivers/vfio/pci/qat/Makefile

@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_QAT_VFIO_PCI) += qat_vfio_pci.o
+qat_vfio_pci-y := main.o