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Commit ffbdd3f7 authored by Alex Williamson's avatar Alex Williamson Committed by Jesse Barnes
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PCI: Add interfaces to store and load the device saved state 



For KVM device assignment, we'd like to save off the state of a device
prior to passing it to the guest and restore it later.  We also want
to allow pci_reset_funciton() to be called while the device is owned
by the guest.  This however overwrites and invalidates the struct pci_dev
buffers, so we can't just manually call save and restore.  Add generic
interfaces for the saved state to be stored and reloaded back into
struct pci_dev at a later time.

Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
parent 24a4742f

drivers/pci/pci.c

+98 −0
Original line number Diff line number Diff line
@@ -976,6 +976,104 @@ void pci_restore_state(struct pci_dev *dev) 
	dev->state_saved = false;

}



struct pci_saved_state {

	u32 config_space[16];

	struct pci_cap_saved_data cap[0];

};



/**

 * pci_store_saved_state - Allocate and return an opaque struct containing

 *			   the device saved state.

 * @dev: PCI device that we're dealing with

 *

 * Rerturn NULL if no state or error.

 */

struct pci_saved_state *pci_store_saved_state(struct pci_dev *dev)

{

	struct pci_saved_state *state;

	struct pci_cap_saved_state *tmp;

	struct pci_cap_saved_data *cap;

	struct hlist_node *pos;

	size_t size;



	if (!dev->state_saved)

		return NULL;



	size = sizeof(*state) + sizeof(struct pci_cap_saved_data);



	hlist_for_each_entry(tmp, pos, &dev->saved_cap_space, next)

		size += sizeof(struct pci_cap_saved_data) + tmp->cap.size;



	state = kzalloc(size, GFP_KERNEL);

	if (!state)

		return NULL;



	memcpy(state->config_space, dev->saved_config_space,

	       sizeof(state->config_space));



	cap = state->cap;

	hlist_for_each_entry(tmp, pos, &dev->saved_cap_space, next) {

		size_t len = sizeof(struct pci_cap_saved_data) + tmp->cap.size;

		memcpy(cap, &tmp->cap, len);

		cap = (struct pci_cap_saved_data *)((u8 *)cap + len);

	}

	/* Empty cap_save terminates list */



	return state;

}

EXPORT_SYMBOL_GPL(pci_store_saved_state);



/**

 * pci_load_saved_state - Reload the provided save state into struct pci_dev.

 * @dev: PCI device that we're dealing with

 * @state: Saved state returned from pci_store_saved_state()

 */

int pci_load_saved_state(struct pci_dev *dev, struct pci_saved_state *state)

{

	struct pci_cap_saved_data *cap;



	dev->state_saved = false;



	if (!state)

		return 0;



	memcpy(dev->saved_config_space, state->config_space,

	       sizeof(state->config_space));



	cap = state->cap;

	while (cap->size) {

		struct pci_cap_saved_state *tmp;



		tmp = pci_find_saved_cap(dev, cap->cap_nr);

		if (!tmp || tmp->cap.size != cap->size)

			return -EINVAL;



		memcpy(tmp->cap.data, cap->data, tmp->cap.size);

		cap = (struct pci_cap_saved_data *)((u8 *)cap +

		       sizeof(struct pci_cap_saved_data) + cap->size);

	}



	dev->state_saved = true;

	return 0;

}

EXPORT_SYMBOL_GPL(pci_load_saved_state);



/**

 * pci_load_and_free_saved_state - Reload the save state pointed to by state,

 *				   and free the memory allocated for it.

 * @dev: PCI device that we're dealing with

 * @state: Pointer to saved state returned from pci_store_saved_state()

 */

int pci_load_and_free_saved_state(struct pci_dev *dev,

				  struct pci_saved_state **state)

{

	int ret = pci_load_saved_state(dev, *state);

	kfree(*state);

	*state = NULL;

	return ret;

}

EXPORT_SYMBOL_GPL(pci_load_and_free_saved_state);



static int do_pci_enable_device(struct pci_dev *dev, int bars)

{

	int err;

include/linux/pci.h

+4 −0
Original line number Diff line number Diff line
@@ -812,6 +812,10 @@ size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size); 
/* Power management related routines */

int pci_save_state(struct pci_dev *dev);

void pci_restore_state(struct pci_dev *dev);

struct pci_saved_state *pci_store_saved_state(struct pci_dev *dev);

int pci_load_saved_state(struct pci_dev *dev, struct pci_saved_state *state);

int pci_load_and_free_saved_state(struct pci_dev *dev,

				  struct pci_saved_state **state);

int __pci_complete_power_transition(struct pci_dev *dev, pci_power_t state);

int pci_set_power_state(struct pci_dev *dev, pci_power_t state);

pci_power_t pci_choose_state(struct pci_dev *dev, pm_message_t state);