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: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This commit is contained in:
Alex Williamson 2011-05-10 10:02:27 -06:00 committed by Jesse Barnes
parent 24a4742f0b
commit ffbdd3f793
2 changed files with 102 additions and 0 deletions

View File

@ -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;

View File

@ -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);