Commit 8129b9e8 authored by Tiwei Bie's avatar Tiwei Bie Committed by Johannes Berg
Browse files

um: vfio: Support adding devices via mconsole 



It can be used when we want to pass through PCI devices to UML
while it's up and running. PCI devices can be passed through to
UML using the same syntax as the command line option:

(mconsole) config vfio_uml.device=<domain:bus:slot.function>

Signed-off-by: default avatarTiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20250709010021.1076902-1-tiwei.bie@linux.dev


Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 4c916e3b

arch/um/drivers/vfio_kern.c

+57 −5
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <init.h>

#include <os.h>



#include "mconsole_kern.h"

#include "virt-pci.h"

#include "vfio_user.h"
@@ -60,6 +61,7 @@ static LIST_HEAD(uml_vfio_groups); 
static DEFINE_MUTEX(uml_vfio_groups_mtx);



static LIST_HEAD(uml_vfio_devices);

static DEFINE_MUTEX(uml_vfio_devices_mtx);



static int uml_vfio_set_container(int group_fd)

{
@@ -581,32 +583,44 @@ static struct uml_vfio_device *uml_vfio_find_device(const char *device) 
	return NULL;

}



static int uml_vfio_cmdline_set(const char *device, const struct kernel_param *kp)

static struct uml_vfio_device *uml_vfio_add_device(const char *device)

{

	struct uml_vfio_device *dev;

	int fd;



	guard(mutex)(&uml_vfio_devices_mtx);



	if (uml_vfio_container.fd < 0) {

		fd = uml_vfio_user_open_container();

		if (fd < 0)

			return fd;

			return ERR_PTR(fd);

		uml_vfio_container.fd = fd;

	}



	if (uml_vfio_find_device(device))

		return -EEXIST;

		return ERR_PTR(-EEXIST);



	dev = kzalloc(sizeof(*dev), GFP_KERNEL);

	if (!dev)

		return -ENOMEM;

		return ERR_PTR(-ENOMEM);



	dev->name = kstrdup(device, GFP_KERNEL);

	if (!dev->name) {

		kfree(dev);

		return -ENOMEM;

		return ERR_PTR(-ENOMEM);

	}



	list_add_tail(&dev->list, &uml_vfio_devices);

	return dev;

}



static int uml_vfio_cmdline_set(const char *device, const struct kernel_param *kp)

{

	struct uml_vfio_device *dev;



	dev = uml_vfio_add_device(device);

	if (IS_ERR(dev))

		return PTR_ERR(dev);

	return 0;

}
@@ -629,6 +643,42 @@ __uml_help(uml_vfio_cmdline_param_ops, 
"    through multiple PCI devices to UML.\n\n"

);



static int uml_vfio_mc_config(char *str, char **error_out)

{

	struct uml_vfio_device *dev;



	if (*str != '=') {

		*error_out = "Invalid config";

		return -EINVAL;

	}

	str += 1;



	dev = uml_vfio_add_device(str);

	if (IS_ERR(dev))

		return PTR_ERR(dev);

	uml_vfio_open_device(dev);

	return 0;

}



static int uml_vfio_mc_id(char **str, int *start_out, int *end_out)

{

	return -EOPNOTSUPP;

}



static int uml_vfio_mc_remove(int n, char **error_out)

{

	return -EOPNOTSUPP;

}



static struct mc_device uml_vfio_mc = {

	.list           = LIST_HEAD_INIT(uml_vfio_mc.list),

	.name           = "vfio_uml.device",

	.config         = uml_vfio_mc_config,

	.get_config     = NULL,

	.id             = uml_vfio_mc_id,

	.remove         = uml_vfio_mc_remove,

};



static int __init uml_vfio_init(void)

{

	struct uml_vfio_device *dev, *n;
@@ -639,6 +689,8 @@ static int __init uml_vfio_init(void) 
	list_for_each_entry_safe(dev, n, &uml_vfio_devices, list)

		uml_vfio_open_device(dev);



	mconsole_register_dev(&uml_vfio_mc);



	return 0;

}

late_initcall(uml_vfio_init);