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Subject[PATCH 6/7] um: add PCI over virtio emulation driver
Date
From: Johannes Berg <johannes.berg@intel.com>

To support testing of PCI/PCIe drivers in UML, add a PCI bus
support driver. This driver uses virtio, which in UML is really
just vhost-user, to talk to devices, and adds the devices to
the virtual PCI bus in the system.

Since virtio already allows DMA/bus mastering this really isn't
all that hard, of course we need the logic_iomem infrastructure
that was added by a previous patch.

The protocol to talk to the device is has a few fairly simple
messages for reading to/writing from config and IO spaces, and
messages for the device to send the various interrupts (INT#,
MSI/MSI-X and while suspended PME#).

Note that currently no offical virtio device ID is assigned for
this protocol, as a consequence this patch requires defining it
in the Kconfig, with a default that makes the driver refuse to
work at all.

Finally, in order to add support for MSI/MSI-X interrupts, some
small changes are needed in the UML IRQ code, it needs to have
more interrupts, changing NR_IRQS from 64 to 128 if this driver
is enabled, but not actually use them for anything so that the
generic IRQ domain/MSI infrastructure can allocate IRQ numbers.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
arch/um/Kconfig | 13 +-
arch/um/drivers/Kconfig | 20 +
arch/um/drivers/Makefile | 1 +
arch/um/drivers/virt-pci.c | 885 +++++++++++++++++++++++++++++
arch/um/include/asm/Kbuild | 1 -
arch/um/include/asm/io.h | 7 +
arch/um/include/asm/irq.h | 8 +-
arch/um/include/asm/msi.h | 1 +
arch/um/include/asm/pci.h | 39 ++
arch/um/kernel/Makefile | 1 +
arch/um/kernel/ioport.c | 13 +
arch/um/kernel/irq.c | 7 +-
include/uapi/linux/virtio_pcidev.h | 64 +++
13 files changed, 1054 insertions(+), 6 deletions(-)
create mode 100644 arch/um/drivers/virt-pci.c
create mode 100644 arch/um/include/asm/msi.h
create mode 100644 arch/um/include/asm/pci.h
create mode 100644 arch/um/kernel/ioport.c
create mode 100644 include/uapi/linux/virtio_pcidev.h

diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index 20b0640e01b8..f64d774706e5 100644
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -14,7 +14,7 @@ config UML
select HAVE_FUTEX_CMPXCHG if FUTEX
select HAVE_DEBUG_KMEMLEAK
select HAVE_DEBUG_BUGVERBOSE
- select NO_DMA
+ select NO_DMA if !UML_DMA_EMULATION
select GENERIC_IRQ_SHOW
select GENERIC_CPU_DEVICES
select HAVE_GCC_PLUGINS
@@ -25,10 +25,21 @@ config MMU
bool
default y

+config UML_DMA_EMULATION
+ bool
+
config NO_IOMEM
bool "disable IOMEM" if EXPERT
+ depends on !INDIRECT_IOMEM
default y

+config UML_IOMEM_EMULATION
+ bool
+ select INDIRECT_IOMEM
+ select GENERIC_PCI_IOMAP
+ select GENERIC_IOMAP
+ select NO_GENERIC_PCI_IOPORT_MAP
+
config NO_IOPORT_MAP
def_bool y

diff --git a/arch/um/drivers/Kconfig b/arch/um/drivers/Kconfig
index 03ba34b61115..f145842c40b9 100644
--- a/arch/um/drivers/Kconfig
+++ b/arch/um/drivers/Kconfig
@@ -357,3 +357,23 @@ config UML_RTC
rtcwake, especially in time-travel mode. This driver enables that
by providing a fake RTC clock that causes a wakeup at the right
time.
+
+config UML_PCI_OVER_VIRTIO
+ bool "Enable PCI over VIRTIO device simulation"
+ # in theory, just VIRTIO is enough, but that causes recursion
+ depends on VIRTIO_UML
+ select FORCE_PCI
+ select UML_IOMEM_EMULATION
+ select UML_DMA_EMULATION
+ select PCI_MSI
+ select PCI_MSI_IRQ_DOMAIN
+ select PCI_LOCKLESS_CONFIG
+
+config UML_PCI_OVER_VIRTIO_DEVICE_ID
+ int "set the virtio device ID for PCI emulation"
+ default -1
+ depends on UML_PCI_OVER_VIRTIO
+ help
+ There's no official device ID assigned (yet), set the one you
+ wish to use for experimentation here. The default of -1 is
+ not valid and will cause the driver to fail at probe.
diff --git a/arch/um/drivers/Makefile b/arch/um/drivers/Makefile
index dcc64a02f81f..803666e85414 100644
--- a/arch/um/drivers/Makefile
+++ b/arch/um/drivers/Makefile
@@ -64,6 +64,7 @@ obj-$(CONFIG_BLK_DEV_COW_COMMON) += cow_user.o
obj-$(CONFIG_UML_RANDOM) += random.o
obj-$(CONFIG_VIRTIO_UML) += virtio_uml.o
obj-$(CONFIG_UML_RTC) += rtc.o
+obj-$(CONFIG_UML_PCI_OVER_VIRTIO) += virt-pci.o

# pcap_user.o must be added explicitly.
USER_OBJS := fd.o null.o pty.o tty.o xterm.o slip_common.o pcap_user.o vde_user.o vector_user.o
diff --git a/arch/um/drivers/virt-pci.c b/arch/um/drivers/virt-pci.c
new file mode 100644
index 000000000000..dd85f36197aa
--- /dev/null
+++ b/arch/um/drivers/virt-pci.c
@@ -0,0 +1,885 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 Intel Corporation
+ * Author: Johannes Berg <johannes@sipsolutions.net>
+ */
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/virtio.h>
+#include <linux/virtio_config.h>
+#include <linux/logic_iomem.h>
+#include <linux/irqdomain.h>
+#include <linux/virtio_pcidev.h>
+#include <linux/delay.h>
+#include <linux/msi.h>
+#include <asm/unaligned.h>
+#include <irq_kern.h>
+
+#define MAX_DEVICES 8
+#define MAX_MSI_VECTORS 32
+#define CFG_SPACE_SIZE 4096
+
+/* for MSI-X we have a 32-bit payload */
+#define MAX_IRQ_MSG_SIZE (sizeof(struct virtio_pcidev_msg) + sizeof(u32))
+#define NUM_IRQ_MSGS 10
+
+#define HANDLE_NO_FREE(ptr) ((void *)((unsigned long)(ptr) | 1))
+#define HANDLE_IS_NO_FREE(ptr) ((unsigned long)(ptr) & 1)
+
+struct um_pci_device {
+ struct virtio_device *vdev;
+
+ /* for now just standard BARs */
+ u8 resptr[PCI_STD_NUM_BARS];
+
+ struct virtqueue *cmd_vq, *irq_vq;
+
+#define UM_PCI_STAT_WAITING 0
+ unsigned long status;
+
+ int irq;
+};
+
+struct um_pci_device_reg {
+ struct um_pci_device *dev;
+ void __iomem *iomem;
+};
+
+static struct pci_host_bridge *bridge;
+static DEFINE_MUTEX(um_pci_mtx);
+static struct um_pci_device_reg um_pci_devices[MAX_DEVICES];
+static struct fwnode_handle *um_pci_fwnode;
+static struct irq_domain *um_pci_inner_domain;
+static struct irq_domain *um_pci_msi_domain;
+static unsigned long um_pci_msi_used[BITS_TO_LONGS(MAX_MSI_VECTORS)];
+
+#define UM_VIRT_PCI_MAXDELAY 40000
+
+static int um_pci_send_cmd(struct um_pci_device *dev,
+ struct virtio_pcidev_msg *cmd,
+ unsigned int cmd_size,
+ const void *extra, unsigned int extra_size,
+ void *out, unsigned int out_size)
+{
+ struct scatterlist out_sg, extra_sg, in_sg;
+ struct scatterlist *sgs_list[] = {
+ [0] = &out_sg,
+ [1] = extra ? &extra_sg : &in_sg,
+ [2] = extra ? &in_sg : NULL,
+ };
+ int delay_count = 0;
+ int ret, len;
+ bool posted;
+
+ if (WARN_ON(cmd_size < sizeof(*cmd)))
+ return -EINVAL;
+
+ switch (cmd->op) {
+ case VIRTIO_PCIDEV_OP_CFG_WRITE:
+ case VIRTIO_PCIDEV_OP_MMIO_WRITE:
+ case VIRTIO_PCIDEV_OP_MMIO_MEMSET:
+ /* in PCI, writes are posted, so don't wait */
+ posted = !out;
+ WARN_ON(!posted);
+ break;
+ default:
+ posted = false;
+ break;
+ }
+
+ if (posted) {
+ u8 *ncmd = kmalloc(cmd_size + extra_size, GFP_ATOMIC);
+
+ if (ncmd) {
+ memcpy(ncmd, cmd, cmd_size);
+ if (extra)
+ memcpy(ncmd + cmd_size, extra, extra_size);
+ cmd = (void *)ncmd;
+ cmd_size += extra_size;
+ extra = NULL;
+ extra_size = 0;
+ } else {
+ /* try without allocating memory */
+ posted = false;
+ }
+ }
+
+ sg_init_one(&out_sg, cmd, cmd_size);
+ if (extra)
+ sg_init_one(&extra_sg, extra, extra_size);
+ if (out)
+ sg_init_one(&in_sg, out, out_size);
+
+ /* add to internal virtio queue */
+ ret = virtqueue_add_sgs(dev->cmd_vq, sgs_list,
+ extra ? 2 : 1,
+ out ? 1 : 0,
+ posted ? cmd : HANDLE_NO_FREE(cmd),
+ GFP_ATOMIC);
+ if (ret)
+ return ret;
+
+ if (posted) {
+ virtqueue_kick(dev->cmd_vq);
+ return 0;
+ }
+
+ /* kick and poll for getting a response on the queue */
+ set_bit(UM_PCI_STAT_WAITING, &dev->status);
+ virtqueue_kick(dev->cmd_vq);
+
+ while (1) {
+ void *completed = virtqueue_get_buf(dev->cmd_vq, &len);
+
+ if (completed == HANDLE_NO_FREE(cmd))
+ break;
+
+ if (WARN_ONCE(virtqueue_is_broken(dev->cmd_vq) ||
+ ++delay_count > UM_VIRT_PCI_MAXDELAY,
+ "um virt-pci delay: %d", delay_count)) {
+ ret = -EIO;
+ break;
+ }
+ udelay(1);
+ }
+ clear_bit(UM_PCI_STAT_WAITING, &dev->status);
+
+ return ret;
+}
+
+static unsigned long um_pci_cfgspace_read(void *priv, unsigned int offset,
+ int size)
+{
+ struct um_pci_device_reg *reg = priv;
+ struct um_pci_device *dev = reg->dev;
+ struct virtio_pcidev_msg hdr = {
+ .op = VIRTIO_PCIDEV_OP_CFG_READ,
+ .size = size,
+ .addr = offset,
+ };
+ /* maximum size - we may only use parts of it */
+ u8 data[8];
+
+ if (!dev)
+ return ~0ULL;
+
+ memset(data, 0xff, sizeof(data));
+
+ switch (size) {
+ case 1:
+ case 2:
+ case 4:
+#ifdef CONFIG_64BIT
+ case 8:
+#endif
+ break;
+ default:
+ WARN(1, "invalid config space read size %d\n", size);
+ return ~0ULL;
+ }
+
+ if (um_pci_send_cmd(dev, &hdr, sizeof(hdr), NULL, 0,
+ data, sizeof(data)))
+ return ~0ULL;
+
+ switch (size) {
+ case 1:
+ return data[0];
+ case 2:
+ return le16_to_cpup((void *)data);
+ case 4:
+ return le32_to_cpup((void *)data);
+#ifdef CONFIG_64BIT
+ case 8:
+ return le64_to_cpup((void *)data);
+#endif
+ default:
+ return ~0ULL;
+ }
+}
+
+static void um_pci_cfgspace_write(void *priv, unsigned int offset, int size,
+ unsigned long val)
+{
+ struct um_pci_device_reg *reg = priv;
+ struct um_pci_device *dev = reg->dev;
+ struct {
+ struct virtio_pcidev_msg hdr;
+ /* maximum size - we may only use parts of it */
+ u8 data[8];
+ } msg = {
+ .hdr = {
+ .op = VIRTIO_PCIDEV_OP_CFG_WRITE,
+ .size = size,
+ .addr = offset,
+ },
+ };
+
+ if (!dev)
+ return;
+
+ switch (size) {
+ case 1:
+ msg.data[0] = (u8)val;
+ break;
+ case 2:
+ put_unaligned_le16(val, (void *)msg.data);
+ break;
+ case 4:
+ put_unaligned_le32(val, (void *)msg.data);
+ break;
+#ifdef CONFIG_64BIT
+ case 8:
+ put_unaligned_le64(val, (void *)msg.data);
+ break;
+#endif
+ default:
+ WARN(1, "invalid config space write size %d\n", size);
+ return;
+ }
+
+ WARN_ON(um_pci_send_cmd(dev, &msg.hdr, sizeof(msg), NULL, 0, NULL, 0));
+}
+
+static const struct logic_iomem_ops um_pci_device_cfgspace_ops = {
+ .read = um_pci_cfgspace_read,
+ .write = um_pci_cfgspace_write,
+};
+
+static void um_pci_bar_copy_from(void *priv, void *buffer,
+ unsigned int offset, int size)
+{
+ u8 *resptr = priv;
+ struct um_pci_device *dev = container_of(resptr - *resptr,
+ struct um_pci_device,
+ resptr[0]);
+ struct virtio_pcidev_msg hdr = {
+ .op = VIRTIO_PCIDEV_OP_MMIO_READ,
+ .bar = *resptr,
+ .size = size,
+ .addr = offset,
+ };
+
+ memset(buffer, 0xff, size);
+
+ um_pci_send_cmd(dev, &hdr, sizeof(hdr), NULL, 0, buffer, size);
+}
+
+static unsigned long um_pci_bar_read(void *priv, unsigned int offset,
+ int size)
+{
+ /* maximum size - we may only use parts of it */
+ u8 data[8];
+
+ switch (size) {
+ case 1:
+ case 2:
+ case 4:
+#ifdef CONFIG_64BIT
+ case 8:
+#endif
+ break;
+ default:
+ WARN(1, "invalid config space read size %d\n", size);
+ return ~0ULL;
+ }
+
+ um_pci_bar_copy_from(priv, data, offset, size);
+
+ switch (size) {
+ case 1:
+ return data[0];
+ case 2:
+ return le16_to_cpup((void *)data);
+ case 4:
+ return le32_to_cpup((void *)data);
+#ifdef CONFIG_64BIT
+ case 8:
+ return le64_to_cpup((void *)data);
+#endif
+ default:
+ return ~0ULL;
+ }
+}
+
+static void um_pci_bar_copy_to(void *priv, unsigned int offset,
+ const void *buffer, int size)
+{
+ u8 *resptr = priv;
+ struct um_pci_device *dev = container_of(resptr - *resptr,
+ struct um_pci_device,
+ resptr[0]);
+ struct virtio_pcidev_msg hdr = {
+ .op = VIRTIO_PCIDEV_OP_MMIO_WRITE,
+ .bar = *resptr,
+ .size = size,
+ .addr = offset,
+ };
+
+ um_pci_send_cmd(dev, &hdr, sizeof(hdr), buffer, size, NULL, 0);
+}
+
+static void um_pci_bar_write(void *priv, unsigned int offset, int size,
+ unsigned long val)
+{
+ /* maximum size - we may only use parts of it */
+ u8 data[8];
+
+ switch (size) {
+ case 1:
+ data[0] = (u8)val;
+ break;
+ case 2:
+ put_unaligned_le16(val, (void *)data);
+ break;
+ case 4:
+ put_unaligned_le32(val, (void *)data);
+ break;
+#ifdef CONFIG_64BIT
+ case 8:
+ put_unaligned_le64(val, (void *)data);
+ break;
+#endif
+ default:
+ WARN(1, "invalid config space write size %d\n", size);
+ return;
+ }
+
+ um_pci_bar_copy_to(priv, offset, data, size);
+}
+
+static void um_pci_bar_set(void *priv, unsigned int offset, u8 value, int size)
+{
+ u8 *resptr = priv;
+ struct um_pci_device *dev = container_of(resptr - *resptr,
+ struct um_pci_device,
+ resptr[0]);
+ struct {
+ struct virtio_pcidev_msg hdr;
+ u8 data;
+ } msg = {
+ .hdr = {
+ .op = VIRTIO_PCIDEV_OP_CFG_WRITE,
+ .bar = *resptr,
+ .size = size,
+ .addr = offset,
+ },
+ .data = value,
+ };
+
+ um_pci_send_cmd(dev, &msg.hdr, sizeof(msg), NULL, 0, NULL, 0);
+}
+
+static const struct logic_iomem_ops um_pci_device_bar_ops = {
+ .read = um_pci_bar_read,
+ .write = um_pci_bar_write,
+ .set = um_pci_bar_set,
+ .copy_from = um_pci_bar_copy_from,
+ .copy_to = um_pci_bar_copy_to,
+};
+
+static void __iomem *um_pci_map_bus(struct pci_bus *bus, unsigned int devfn,
+ int where)
+{
+ struct um_pci_device_reg *dev;
+ unsigned int busn = bus->number;
+
+ if (busn > 0)
+ return NULL;
+
+ /* not allowing functions for now ... */
+ if (devfn % 8)
+ return NULL;
+
+ if (devfn / 8 >= ARRAY_SIZE(um_pci_devices))
+ return NULL;
+
+ dev = &um_pci_devices[devfn / 8];
+ if (!dev)
+ return NULL;
+
+ return (void __iomem *)((unsigned long)dev->iomem + where);
+}
+
+static struct pci_ops um_pci_ops = {
+ .map_bus = um_pci_map_bus,
+ .read = pci_generic_config_read,
+ .write = pci_generic_config_write,
+};
+
+static void um_pci_rescan(void)
+{
+ pci_lock_rescan_remove();
+ pci_rescan_bus(bridge->bus);
+ pci_unlock_rescan_remove();
+}
+
+static void um_pci_irq_vq_addbuf(struct virtqueue *vq, void *buf, bool kick)
+{
+ struct scatterlist sg[1];
+
+ sg_init_one(sg, buf, MAX_IRQ_MSG_SIZE);
+ if (virtqueue_add_inbuf(vq, sg, 1, buf, GFP_ATOMIC))
+ kfree(buf);
+ else if (kick)
+ virtqueue_kick(vq);
+}
+
+static void um_pci_handle_irq_message(struct virtqueue *vq,
+ struct virtio_pcidev_msg *msg)
+{
+ struct virtio_device *vdev = vq->vdev;
+ struct um_pci_device *dev = vdev->priv;
+
+ /* we should properly chain interrupts, but on ARCH=um we don't care */
+
+ switch (msg->op) {
+ case VIRTIO_PCIDEV_OP_INT:
+ generic_handle_irq(dev->irq);
+ break;
+ case VIRTIO_PCIDEV_OP_MSI:
+ /* our MSI message is just the interrupt number */
+ if (msg->size == sizeof(u32))
+ generic_handle_irq(le32_to_cpup((void *)msg->data));
+ else
+ generic_handle_irq(le16_to_cpup((void *)msg->data));
+ break;
+ case VIRTIO_PCIDEV_OP_PME:
+ /* nothing to do - we already woke up due to the message */
+ break;
+ default:
+ dev_err(&vdev->dev, "unexpected virt-pci message %d\n", msg->op);
+ break;
+ }
+}
+
+static void um_pci_cmd_vq_cb(struct virtqueue *vq)
+{
+ struct virtio_device *vdev = vq->vdev;
+ struct um_pci_device *dev = vdev->priv;
+ void *cmd;
+ int len;
+
+ if (test_bit(UM_PCI_STAT_WAITING, &dev->status))
+ return;
+
+ while ((cmd = virtqueue_get_buf(vq, &len))) {
+ if (WARN_ON(HANDLE_IS_NO_FREE(cmd)))
+ continue;
+ kfree(cmd);
+ }
+}
+
+static void um_pci_irq_vq_cb(struct virtqueue *vq)
+{
+ struct virtio_pcidev_msg *msg;
+ int len;
+
+ while ((msg = virtqueue_get_buf(vq, &len))) {
+ if (len >= sizeof(*msg))
+ um_pci_handle_irq_message(vq, msg);
+
+ /* recycle the message buffer */
+ um_pci_irq_vq_addbuf(vq, msg, true);
+ }
+}
+
+static int um_pci_init_vqs(struct um_pci_device *dev)
+{
+ struct virtqueue *vqs[2];
+ static const char *const names[2] = { "cmd", "irq" };
+ vq_callback_t *cbs[2] = { um_pci_cmd_vq_cb, um_pci_irq_vq_cb };
+ int err, i;
+
+ err = virtio_find_vqs(dev->vdev, 2, vqs, cbs, names, NULL);
+ if (err)
+ return err;
+
+ dev->cmd_vq = vqs[0];
+ dev->irq_vq = vqs[1];
+
+ for (i = 0; i < NUM_IRQ_MSGS; i++) {
+ void *msg = kzalloc(MAX_IRQ_MSG_SIZE, GFP_KERNEL);
+
+ if (msg)
+ um_pci_irq_vq_addbuf(dev->irq_vq, msg, false);
+ }
+
+ virtqueue_kick(dev->irq_vq);
+
+ return 0;
+}
+
+static int um_pci_virtio_probe(struct virtio_device *vdev)
+{
+ struct um_pci_device *dev;
+ int i, free = -1;
+ int err = -ENOSPC;
+
+ dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+ if (!dev)
+ return -ENOMEM;
+
+ dev->vdev = vdev;
+ vdev->priv = dev;
+
+ mutex_lock(&um_pci_mtx);
+ for (i = 0; i < MAX_DEVICES; i++) {
+ if (um_pci_devices[i].dev)
+ continue;
+ free = i;
+ break;
+ }
+
+ if (free < 0)
+ goto error;
+
+ err = um_pci_init_vqs(dev);
+ if (err)
+ goto error;
+
+ dev->irq = irq_alloc_desc(numa_node_id());
+ if (dev->irq < 0) {
+ err = dev->irq;
+ goto error;
+ }
+ um_pci_devices[free].dev = dev;
+ vdev->priv = dev;
+
+ mutex_unlock(&um_pci_mtx);
+
+ device_set_wakeup_enable(&vdev->dev, true);
+
+ um_pci_rescan();
+ return 0;
+error:
+ mutex_unlock(&um_pci_mtx);
+ kfree(dev);
+ return err;
+}
+
+static void um_pci_virtio_remove(struct virtio_device *vdev)
+{
+ struct um_pci_device *dev = vdev->priv;
+ int i;
+
+ /* Stop all virtqueues */
+ vdev->config->reset(vdev);
+ vdev->config->del_vqs(vdev);
+
+ device_set_wakeup_enable(&vdev->dev, false);
+
+ mutex_lock(&um_pci_mtx);
+ for (i = 0; i < MAX_DEVICES; i++) {
+ if (um_pci_devices[i].dev != dev)
+ continue;
+ um_pci_devices[i].dev = NULL;
+ irq_free_desc(dev->irq);
+ }
+ mutex_unlock(&um_pci_mtx);
+
+ um_pci_rescan();
+
+ kfree(dev);
+}
+
+static struct virtio_device_id id_table[] = {
+ { CONFIG_UML_PCI_OVER_VIRTIO_DEVICE_ID, VIRTIO_DEV_ANY_ID },
+ { 0 },
+};
+MODULE_DEVICE_TABLE(virtio, id_table);
+
+static struct virtio_driver um_pci_virtio_driver = {
+ .driver.name = "virtio-pci",
+ .driver.owner = THIS_MODULE,
+ .id_table = id_table,
+ .probe = um_pci_virtio_probe,
+ .remove = um_pci_virtio_remove,
+};
+
+static struct resource virt_cfgspace_resource = {
+ .name = "PCI config space",
+ .start = 0xf0000000 - MAX_DEVICES * CFG_SPACE_SIZE,
+ .end = 0xf0000000 - 1,
+ .flags = IORESOURCE_MEM,
+};
+
+static long um_pci_map_cfgspace(unsigned long offset, size_t size,
+ const struct logic_iomem_ops **ops,
+ void **priv)
+{
+ if (WARN_ON(size > CFG_SPACE_SIZE || offset % CFG_SPACE_SIZE))
+ return -EINVAL;
+
+ if (offset / CFG_SPACE_SIZE < MAX_DEVICES) {
+ *ops = &um_pci_device_cfgspace_ops;
+ *priv = &um_pci_devices[offset / CFG_SPACE_SIZE];
+ return 0;
+ }
+
+ WARN(1, "cannot map offset 0x%lx/0x%zx\n", offset, size);
+ return -ENOENT;
+}
+
+static const struct logic_iomem_region_ops um_pci_cfgspace_ops = {
+ .map = um_pci_map_cfgspace,
+};
+
+static struct resource virt_iomem_resource = {
+ .name = "PCI iomem",
+ .start = 0xf0000000,
+ .end = 0xffffffff,
+ .flags = IORESOURCE_MEM,
+};
+
+struct um_pci_map_iomem_data {
+ unsigned long offset;
+ size_t size;
+ const struct logic_iomem_ops **ops;
+ void **priv;
+ long ret;
+};
+
+static int um_pci_map_iomem_walk(struct pci_dev *pdev, void *_data)
+{
+ struct um_pci_map_iomem_data *data = _data;
+ struct um_pci_device_reg *reg = &um_pci_devices[pdev->devfn / 8];
+ struct um_pci_device *dev;
+ int i;
+
+ if (!reg->dev)
+ return 0;
+
+ for (i = 0; i < ARRAY_SIZE(dev->resptr); i++) {
+ struct resource *r = &pdev->resource[i];
+
+ if ((r->flags & IORESOURCE_TYPE_BITS) != IORESOURCE_MEM)
+ continue;
+
+ /*
+ * must be the whole or part of the resource,
+ * not allowed to only overlap
+ */
+ if (data->offset < r->start || data->offset > r->end)
+ continue;
+ if (data->offset + data->size - 1 > r->end)
+ continue;
+
+ dev = reg->dev;
+ *data->ops = &um_pci_device_bar_ops;
+ dev->resptr[i] = i;
+ *data->priv = &dev->resptr[i];
+ data->ret = data->offset - r->start;
+
+ /* no need to continue */
+ return 1;
+ }
+
+ return 0;
+}
+
+static long um_pci_map_iomem(unsigned long offset, size_t size,
+ const struct logic_iomem_ops **ops,
+ void **priv)
+{
+ struct um_pci_map_iomem_data data = {
+ /* we want the full address here */
+ .offset = offset + virt_iomem_resource.start,
+ .size = size,
+ .ops = ops,
+ .priv = priv,
+ .ret = -ENOENT,
+ };
+
+ pci_walk_bus(bridge->bus, um_pci_map_iomem_walk, &data);
+ return data.ret;
+}
+
+static const struct logic_iomem_region_ops um_pci_iomem_ops = {
+ .map = um_pci_map_iomem,
+};
+
+static void um_pci_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
+{
+ /*
+ * This is a very low address and not actually valid 'physical' memory
+ * in UML, so we can simply map MSI(-X) vectors to there, it cannot be
+ * legitimately written to by the device in any other way.
+ * We use the (virtual) IRQ number here as the message to simplify the
+ * code that receives the message, where for now we simply trust the
+ * device to send the correct message.
+ */
+ msg->address_hi = 0;
+ msg->address_lo = 0xa0000;
+ msg->data = data->irq;
+}
+
+static struct irq_chip um_pci_msi_bottom_irq_chip = {
+ .name = "UM virtio MSI",
+ .irq_compose_msi_msg = um_pci_compose_msi_msg,
+};
+
+static int um_pci_inner_domain_alloc(struct irq_domain *domain,
+ unsigned int virq, unsigned int nr_irqs,
+ void *args)
+{
+ unsigned long bit;
+
+ WARN_ON(nr_irqs != 1);
+
+ mutex_lock(&um_pci_mtx);
+ bit = find_first_zero_bit(um_pci_msi_used, MAX_MSI_VECTORS);
+ if (bit >= MAX_MSI_VECTORS) {
+ mutex_unlock(&um_pci_mtx);
+ return -ENOSPC;
+ }
+
+ set_bit(bit, um_pci_msi_used);
+ mutex_unlock(&um_pci_mtx);
+
+ irq_domain_set_info(domain, virq, bit, &um_pci_msi_bottom_irq_chip,
+ domain->host_data, handle_simple_irq,
+ NULL, NULL);
+
+ return 0;
+}
+
+static void um_pci_inner_domain_free(struct irq_domain *domain,
+ unsigned int virq, unsigned int nr_irqs)
+{
+ struct irq_data *d = irq_domain_get_irq_data(domain, virq);
+
+ mutex_lock(&um_pci_mtx);
+
+ if (!test_bit(d->hwirq, um_pci_msi_used))
+ pr_err("trying to free unused MSI#%lu\n", d->hwirq);
+ else
+ __clear_bit(d->hwirq, um_pci_msi_used);
+
+ mutex_unlock(&um_pci_mtx);
+}
+
+static const struct irq_domain_ops um_pci_inner_domain_ops = {
+ .alloc = um_pci_inner_domain_alloc,
+ .free = um_pci_inner_domain_free,
+};
+
+static struct irq_chip um_pci_msi_irq_chip = {
+ .name = "UM virtio PCIe MSI",
+ .irq_mask = pci_msi_mask_irq,
+ .irq_unmask = pci_msi_unmask_irq,
+};
+
+static struct msi_domain_info um_pci_msi_domain_info = {
+ .flags = MSI_FLAG_USE_DEF_DOM_OPS |
+ MSI_FLAG_USE_DEF_CHIP_OPS |
+ MSI_FLAG_PCI_MSIX,
+ .chip = &um_pci_msi_irq_chip,
+};
+
+static struct resource busn_resource = {
+ .name = "PCI busn",
+ .start = 0,
+ .end = 0,
+ .flags = IORESOURCE_BUS,
+};
+
+static int um_pci_map_irq(const struct pci_dev *pdev, u8 slot, u8 pin)
+{
+ struct um_pci_device_reg *reg = &um_pci_devices[pdev->devfn / 8];
+
+ if (WARN_ON(!reg->dev))
+ return -EINVAL;
+
+ /* Yes, we map all pins to the same IRQ ... doesn't matter for now. */
+ return reg->dev->irq;
+}
+
+void *pci_root_bus_fwnode(struct pci_bus *bus)
+{
+ return um_pci_fwnode;
+}
+
+int um_pci_init(void)
+{
+ int err, i;
+
+ WARN_ON(logic_iomem_add_region(&virt_cfgspace_resource,
+ &um_pci_cfgspace_ops));
+ WARN_ON(logic_iomem_add_region(&virt_iomem_resource,
+ &um_pci_iomem_ops));
+
+ if (WARN(CONFIG_UML_PCI_OVER_VIRTIO_DEVICE_ID < 0,
+ "No virtio device ID configured for PCI - no PCI support\n"))
+ return 0;
+
+ bridge = pci_alloc_host_bridge(0);
+ if (!bridge)
+ return -ENOMEM;
+
+ um_pci_fwnode = irq_domain_alloc_named_fwnode("um-pci");
+ if (!um_pci_fwnode) {
+ err = -ENOMEM;
+ goto free;
+ }
+
+ um_pci_inner_domain = __irq_domain_add(um_pci_fwnode, MAX_MSI_VECTORS,
+ MAX_MSI_VECTORS, 0,
+ &um_pci_inner_domain_ops, NULL);
+ if (!um_pci_inner_domain) {
+ err = -ENOMEM;
+ goto free;
+ }
+
+ um_pci_msi_domain = pci_msi_create_irq_domain(um_pci_fwnode,
+ &um_pci_msi_domain_info,
+ um_pci_inner_domain);
+ if (!um_pci_msi_domain) {
+ err = -ENOMEM;
+ goto free;
+ }
+
+ pci_add_resource(&bridge->windows, &virt_iomem_resource);
+ pci_add_resource(&bridge->windows, &busn_resource);
+ bridge->ops = &um_pci_ops;
+ bridge->map_irq = um_pci_map_irq;
+
+ for (i = 0; i < MAX_DEVICES; i++) {
+ resource_size_t start;
+
+ start = virt_cfgspace_resource.start + i * CFG_SPACE_SIZE;
+ um_pci_devices[i].iomem = ioremap(start, CFG_SPACE_SIZE);
+ if (WARN(!um_pci_devices[i].iomem, "failed to map %d\n", i)) {
+ err = -ENOMEM;
+ goto free;
+ }
+ }
+
+ err = pci_host_probe(bridge);
+ if (err)
+ goto free;
+
+ err = register_virtio_driver(&um_pci_virtio_driver);
+ if (err)
+ goto free;
+ return 0;
+free:
+ if (um_pci_inner_domain)
+ irq_domain_remove(um_pci_inner_domain);
+ if (um_pci_fwnode)
+ irq_domain_free_fwnode(um_pci_fwnode);
+ pci_free_resource_list(&bridge->windows);
+ pci_free_host_bridge(bridge);
+ return err;
+}
+module_init(um_pci_init);
+
+void um_pci_exit(void)
+{
+ unregister_virtio_driver(&um_pci_virtio_driver);
+ irq_domain_remove(um_pci_msi_domain);
+ irq_domain_remove(um_pci_inner_domain);
+ pci_free_resource_list(&bridge->windows);
+ pci_free_host_bridge(bridge);
+}
+module_exit(um_pci_exit);
diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild
index a58811dc054c..665b81fc261d 100644
--- a/arch/um/include/asm/Kbuild
+++ b/arch/um/include/asm/Kbuild
@@ -17,7 +17,6 @@ generic-y += mcs_spinlock.h
generic-y += mmiowb.h
generic-y += module.lds.h
generic-y += param.h
-generic-y += pci.h
generic-y += percpu.h
generic-y += preempt.h
generic-y += switch_to.h
diff --git a/arch/um/include/asm/io.h b/arch/um/include/asm/io.h
index 6ce18d343997..9ea42cc746d9 100644
--- a/arch/um/include/asm/io.h
+++ b/arch/um/include/asm/io.h
@@ -3,16 +3,23 @@
#define _ASM_UM_IO_H
#include <linux/types.h>

+/* get emulated iomem (if desired) */
+#include <asm-generic/logic_io.h>
+
+#ifndef ioremap
#define ioremap ioremap
static inline void __iomem *ioremap(phys_addr_t offset, size_t size)
{
return NULL;
}
+#endif /* ioremap */

+#ifndef iounmap
#define iounmap iounmap
static inline void iounmap(void __iomem *addr)
{
}
+#endif /* iounmap */

#include <asm-generic/io.h>

diff --git a/arch/um/include/asm/irq.h b/arch/um/include/asm/irq.h
index 3f5d3e8228fc..e187c789369d 100644
--- a/arch/um/include/asm/irq.h
+++ b/arch/um/include/asm/irq.h
@@ -31,7 +31,13 @@

#endif

-#define NR_IRQS 64
+#define UM_LAST_SIGNAL_IRQ 64
+/* If we have (simulated) PCI MSI, allow 64 more interrupt numbers for it */
+#ifdef CONFIG_PCI_MSI
+#define NR_IRQS (UM_LAST_SIGNAL_IRQ + 64)
+#else
+#define NR_IRQS UM_LAST_SIGNAL_IRQ
+#endif /* CONFIG_PCI_MSI */

#include <asm-generic/irq.h>
#endif
diff --git a/arch/um/include/asm/msi.h b/arch/um/include/asm/msi.h
new file mode 100644
index 000000000000..c8c6c381f394
--- /dev/null
+++ b/arch/um/include/asm/msi.h
@@ -0,0 +1 @@
+#include <asm-generic/msi.h>
diff --git a/arch/um/include/asm/pci.h b/arch/um/include/asm/pci.h
new file mode 100644
index 000000000000..da13fd5519ef
--- /dev/null
+++ b/arch/um/include/asm/pci.h
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __ASM_UM_PCI_H
+#define __ASM_UM_PCI_H
+#include <linux/types.h>
+#include <asm/io.h>
+
+#define PCIBIOS_MIN_IO 0
+#define PCIBIOS_MIN_MEM 0
+
+#define pcibios_assign_all_busses() 1
+
+extern int isa_dma_bridge_buggy;
+
+#ifdef CONFIG_PCI
+static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
+{
+ /* no legacy IRQs */
+ return -ENODEV;
+}
+#endif
+
+#ifdef CONFIG_PCI_DOMAINS
+static inline int pci_proc_domain(struct pci_bus *bus)
+{
+ /* always show the domain in /proc */
+ return 1;
+}
+#endif /* CONFIG_PCI */
+
+#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
+/*
+ * This is a bit of an annoying hack, and it assumes we only have
+ * the virt-pci (if anything). Which is true, but still.
+ */
+void *pci_root_bus_fwnode(struct pci_bus *bus);
+#define pci_root_bus_fwnode pci_root_bus_fwnode
+#endif
+
+#endif /* __ASM_UM_PCI_H */
diff --git a/arch/um/kernel/Makefile b/arch/um/kernel/Makefile
index 5aa882011e04..c1205f9ec17e 100644
--- a/arch/um/kernel/Makefile
+++ b/arch/um/kernel/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_GPROF) += gprof_syms.o
obj-$(CONFIG_GCOV) += gmon_syms.o
obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
+obj-$(CONFIG_GENERIC_PCI_IOMAP) += ioport.o

USER_OBJS := config.o

diff --git a/arch/um/kernel/ioport.c b/arch/um/kernel/ioport.c
new file mode 100644
index 000000000000..7220615b3beb
--- /dev/null
+++ b/arch/um/kernel/ioport.c
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 Intel Corporation
+ * Author: Johannes Berg <johannes@sipsolutions.net>
+ */
+#include <asm/iomap.h>
+#include <asm-generic/pci_iomap.h>
+
+void __iomem *__pci_ioport_map(struct pci_dev *dev, unsigned long port,
+ unsigned int nr)
+{
+ return NULL;
+}
diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c
index 3718a5cdbc85..5a431f44f1fb 100644
--- a/arch/um/kernel/irq.c
+++ b/arch/um/kernel/irq.c
@@ -56,7 +56,7 @@ struct irq_entry {

static DEFINE_SPINLOCK(irq_lock);
static LIST_HEAD(active_fds);
-static DECLARE_BITMAP(irqs_allocated, NR_IRQS);
+static DECLARE_BITMAP(irqs_allocated, UM_LAST_SIGNAL_IRQ);
static bool irqs_suspended;

static void irq_io_loop(struct irq_reg *irq, struct uml_pt_regs *regs)
@@ -422,7 +422,8 @@ unsigned int do_IRQ(int irq, struct uml_pt_regs *regs)

void um_free_irq(int irq, void *dev)
{
- if (WARN(irq < 0 || irq > NR_IRQS, "freeing invalid irq %d", irq))
+ if (WARN(irq < 0 || irq > UM_LAST_SIGNAL_IRQ,
+ "freeing invalid irq %d", irq))
return;

free_irq_by_irq_and_dev(irq, dev);
@@ -651,7 +652,7 @@ void __init init_IRQ(void)

irq_set_chip_and_handler(TIMER_IRQ, &alarm_irq_type, handle_edge_irq);

- for (i = 1; i < NR_IRQS; i++)
+ for (i = 1; i < UM_LAST_SIGNAL_IRQ; i++)
irq_set_chip_and_handler(i, &normal_irq_type, handle_edge_irq);
/* Initialize EPOLL Loop */
os_setup_epoll();
diff --git a/include/uapi/linux/virtio_pcidev.h b/include/uapi/linux/virtio_pcidev.h
new file mode 100644
index 000000000000..89daa88bcfef
--- /dev/null
+++ b/include/uapi/linux/virtio_pcidev.h
@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */
+/*
+ * Copyright (C) 2021 Intel Corporation
+ * Author: Johannes Berg <johannes@sipsolutions.net>
+ */
+#ifndef _UAPI_LINUX_VIRTIO_PCIDEV_H
+#define _UAPI_LINUX_VIRTIO_PCIDEV_H
+#include <linux/types.h>
+
+/**
+ * enum virtio_pcidev_ops - virtual PCI device operations
+ * @VIRTIO_PCIDEV_OP_CFG_READ: read config space, size is 1, 2, 4 or 8;
+ * the @data field should be filled in by the device (in little endian).
+ * @VIRTIO_PCIDEV_OP_CFG_WRITE: write config space, size is 1, 2, 4 or 8;
+ * the @data field contains the data to write (in little endian).
+ * @VIRTIO_PCIDEV_OP_BAR_READ: read BAR mem/pio, size can be variable;
+ * the @data field should be filled in by the device (in little endian).
+ * @VIRTIO_PCIDEV_OP_BAR_WRITE: write BAR mem/pio, size can be variable;
+ * the @data field contains the data to write (in little endian).
+ * @VIRTIO_PCIDEV_OP_MMIO_MEMSET: memset MMIO, size is variable but
+ * the @data field only has one byte (unlike @VIRTIO_PCIDEV_OP_MMIO_WRITE)
+ * @VIRTIO_PCIDEV_OP_INT: legacy INTx# pin interrupt, the addr field is 1-4 for
+ * the number
+ * @VIRTIO_PCIDEV_OP_MSI: MSI(-X) interrupt, this message basically transports
+ * the 16- or 32-bit write that would otherwise be done into memory,
+ * analogous to the write messages (@VIRTIO_PCIDEV_OP_MMIO_WRITE) above
+ * @VIRTIO_PCIDEV_OP_PME: Dummy message whose content is ignored (and should be
+ * all zeroes) to signal the PME# pin.
+ */
+enum virtio_pcidev_ops {
+ VIRTIO_PCIDEV_OP_RESERVED = 0,
+ VIRTIO_PCIDEV_OP_CFG_READ,
+ VIRTIO_PCIDEV_OP_CFG_WRITE,
+ VIRTIO_PCIDEV_OP_MMIO_READ,
+ VIRTIO_PCIDEV_OP_MMIO_WRITE,
+ VIRTIO_PCIDEV_OP_MMIO_MEMSET,
+ VIRTIO_PCIDEV_OP_INT,
+ VIRTIO_PCIDEV_OP_MSI,
+ VIRTIO_PCIDEV_OP_PME,
+};
+
+/**
+ * struct virtio_pcidev_msg - virtio PCI device operation
+ * @op: the operation to do
+ * @bar: the bar (only with BAR read/write messages)
+ * @reserved: reserved
+ * @size: the size of the read/write (in bytes)
+ * @addr: the address to read/write
+ * @data: the data, normally @size long, but just one byte for
+ * %VIRTIO_PCIDEV_OP_MMIO_MEMSET
+ *
+ * Note: the fields are all in native (CPU) endian, however, the
+ * @data values will often be in little endian (see the ops above.)
+ */
+struct virtio_pcidev_msg {
+ __u8 op;
+ __u8 bar;
+ __u16 reserved;
+ __u32 size;
+ __u64 addr;
+ __u8 data[];
+};
+
+#endif /* _UAPI_LINUX_VIRTIO_PCIDEV_H */
--
2.26.2
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