virtio-pci: introduce modern device module

Signed-off-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210104065503.199631-17-jasowang@redhat.com

Including a bugfix:

virtio: don't prompt CONFIG_VIRTIO_PCI_MODERN

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Anders Roxell <anders.roxell@linaro.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Fixes: 86b87c9d858b6 ("virtio-pci: introduce modern device module")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20210223061905.422659-2-jasowang@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/virtio/Kconfig

@@ -12,6 +12,14 @@ config ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
 	  This option is selected if the architecture may need to enforce
 	  VIRTIO_F_ACCESS_PLATFORM
 
+config VIRTIO_PCI_LIB
+	tristate
+	help
+	  Modern PCI device implementation. This module implements the
+	  basic probe and control for devices which are based on modern
+	  PCI device with possible vendor specific extensions. Any
+	  module that selects this module must depend on PCI.
+
 menuconfig VIRTIO_MENU
 	bool "Virtio drivers"
 	default y
@@ -21,6 +29,7 @@ if VIRTIO_MENU
 config VIRTIO_PCI
 	tristate "PCI driver for virtio devices"
 	depends on PCI
+	select VIRTIO_PCI_LIB
 	select VIRTIO
 	help
 	  This driver provides support for virtio based paravirtual device

drivers/virtio/Makefile

@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_VIRTIO) += virtio.o virtio_ring.o
+obj-$(CONFIG_VIRTIO_PCI_LIB) += virtio_pci_modern_dev.o
 obj-$(CONFIG_VIRTIO_MMIO) += virtio_mmio.o
 obj-$(CONFIG_VIRTIO_PCI) += virtio_pci.o
 virtio_pci-y := virtio_pci_modern.o virtio_pci_common.o

drivers/virtio/virtio_pci_common.h

@@ -25,6 +25,7 @@
 #include <linux/virtio_config.h>
 #include <linux/virtio_ring.h>
 #include <linux/virtio_pci.h>
+#include <linux/virtio_pci_modern.h>
 #include <linux/highmem.h>
 #include <linux/spinlock.h>
 
@@ -39,32 +40,6 @@ struct virtio_pci_vq_info {
 	unsigned msix_vector;
 };
 
-struct virtio_pci_modern_device {
-	struct pci_dev *pci_dev;
-
-	struct virtio_pci_common_cfg __iomem *common;
-	/* Device-specific data (non-legacy mode)  */
-	void __iomem *device;
-	/* Base of vq notifications (non-legacy mode). */
-	void __iomem *notify_base;
-	/* Where to read and clear interrupt */
-	u8 __iomem *isr;
-
-	/* So we can sanity-check accesses. */
-	size_t notify_len;
-	size_t device_len;
-
-	/* Capability for when we need to map notifications per-vq. */
-	int notify_map_cap;
-
-	/* Multiply queue_notify_off by this value. (non-legacy mode). */
-	u32 notify_offset_multiplier;
-
-	int modern_bars;
-
-	struct virtio_device_id id;
-};
-
 /* Our device structure */
 struct virtio_pci_device {
 	struct virtio_device vdev;

include/linux/virtio_pci_modern.h

@@ -0,0 +1,111 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_VIRTIO_PCI_MODERN_H
+#define _LINUX_VIRTIO_PCI_MODERN_H
+
+#include <linux/pci.h>
+#include <linux/virtio_pci.h>
+
+struct virtio_pci_modern_device {
+	struct pci_dev *pci_dev;
+
+	struct virtio_pci_common_cfg __iomem *common;
+	/* Device-specific data (non-legacy mode)  */
+	void __iomem *device;
+	/* Base of vq notifications (non-legacy mode). */
+	void __iomem *notify_base;
+	/* Where to read and clear interrupt */
+	u8 __iomem *isr;
+
+	/* So we can sanity-check accesses. */
+	size_t notify_len;
+	size_t device_len;
+
+	/* Capability for when we need to map notifications per-vq. */
+	int notify_map_cap;
+
+	/* Multiply queue_notify_off by this value. (non-legacy mode). */
+	u32 notify_offset_multiplier;
+
+	int modern_bars;
+
+	struct virtio_device_id id;
+};
+
+/*
+ * Type-safe wrappers for io accesses.
+ * Use these to enforce at compile time the following spec requirement:
+ *
+ * The driver MUST access each field using the “natural” access
+ * method, i.e. 32-bit accesses for 32-bit fields, 16-bit accesses
+ * for 16-bit fields and 8-bit accesses for 8-bit fields.
+ */
+static inline u8 vp_ioread8(const u8 __iomem *addr)
+{
+	return ioread8(addr);
+}
+static inline u16 vp_ioread16 (const __le16 __iomem *addr)
+{
+	return ioread16(addr);
+}
+
+static inline u32 vp_ioread32(const __le32 __iomem *addr)
+{
+	return ioread32(addr);
+}
+
+static inline void vp_iowrite8(u8 value, u8 __iomem *addr)
+{
+	iowrite8(value, addr);
+}
+
+static inline void vp_iowrite16(u16 value, __le16 __iomem *addr)
+{
+	iowrite16(value, addr);
+}
+
+static inline void vp_iowrite32(u32 value, __le32 __iomem *addr)
+{
+	iowrite32(value, addr);
+}
+
+static inline void vp_iowrite64_twopart(u64 val,
+					__le32 __iomem *lo,
+					__le32 __iomem *hi)
+{
+	vp_iowrite32((u32)val, lo);
+	vp_iowrite32(val >> 32, hi);
+}
+
+u64 vp_modern_get_features(struct virtio_pci_modern_device *mdev);
+void vp_modern_set_features(struct virtio_pci_modern_device *mdev,
+		     u64 features);
+u32 vp_modern_generation(struct virtio_pci_modern_device *mdev);
+u8 vp_modern_get_status(struct virtio_pci_modern_device *mdev);
+void vp_modern_set_status(struct virtio_pci_modern_device *mdev,
+		   u8 status);
+u16 vp_modern_queue_vector(struct virtio_pci_modern_device *mdev,
+			   u16 idx, u16 vector);
+u16 vp_modern_config_vector(struct virtio_pci_modern_device *mdev,
+		     u16 vector);
+void vp_modern_queue_address(struct virtio_pci_modern_device *mdev,
+			     u16 index, u64 desc_addr, u64 driver_addr,
+			     u64 device_addr);
+void vp_modern_set_queue_enable(struct virtio_pci_modern_device *mdev,
+				u16 idx, bool enable);
+bool vp_modern_get_queue_enable(struct virtio_pci_modern_device *mdev,
+				u16 idx);
+void vp_modern_set_queue_size(struct virtio_pci_modern_device *mdev,
+			      u16 idx, u16 size);
+u16 vp_modern_get_queue_size(struct virtio_pci_modern_device *mdev,
+			     u16 idx);
+u16 vp_modern_get_num_queues(struct virtio_pci_modern_device *mdev);
+u16 vp_modern_get_queue_notify_off(struct virtio_pci_modern_device *mdev,
+				   u16 idx);
+void __iomem *vp_modern_map_capability(struct virtio_pci_modern_device *mdev, int off,
+				       size_t minlen,
+				       u32 align,
+				       u32 start, u32 size,
+				       size_t *len);
+int vp_modern_probe(struct virtio_pci_modern_device *mdev);
+void vp_modern_remove(struct virtio_pci_modern_device *mdev);
+#endif