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pci: implement power state

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This allows to power off pci devices.  In "off" state the devices will
not be visible.  No pci config space access, no pci bar access, no dma.

Default state is "on", so this patch (alone) should not change behavior.

Use case:  Allows hotplug controllers implement slot power.  Hotplug
controllers doing so should set the inital power state for devices in
the ->plug callback.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-Id: <20211111130859.1171890-2-kraxel@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Gerd Hoffmann 2021-11-11 14:08:54 +01:00 committed by Michael S. Tsirkin
parent c829540401
commit 23786d1344
3 changed files with 29 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
hw/pci/pci.c
View File

@ -1380,6 +1380,9 @@ static void pci_update_mappings(PCIDevice *d)
continue;
new_addr = pci_bar_address(d, i, r->type, r->size);
if (!d->has_power) {
new_addr = PCI_BAR_UNMAPPED;
}
/* This bar isn't changed */
if (new_addr == r->addr)
@ -1464,8 +1467,8 @@ void pci_default_write_config(PCIDevice *d, uint32_t addr, uint32_t val_in, int
if (range_covers_byte(addr, l, PCI_COMMAND)) {
pci_update_irq_disabled(d, was_irq_disabled);
memory_region_set_enabled(&d->bus_master_enable_region,
pci_get_word(d->config + PCI_COMMAND)
& PCI_COMMAND_MASTER);
(pci_get_word(d->config + PCI_COMMAND)
& PCI_COMMAND_MASTER) && d->has_power);
}
msi_write_config(d, addr, val_in, l);
@ -2182,6 +2185,8 @@ static void pci_qdev_realize(DeviceState *qdev, Error **errp)
pci_qdev_unrealize(DEVICE(pci_dev));
return;
}
pci_set_power(pci_dev, true);
}
PCIDevice *pci_new_multifunction(int devfn, bool multifunction,
@ -2853,6 +2858,22 @@ MSIMessage pci_get_msi_message(PCIDevice *dev, int vector)
return msg;
}
void pci_set_power(PCIDevice *d, bool state)
{
if (d->has_power == state) {
return;
}
d->has_power = state;
pci_update_mappings(d);
memory_region_set_enabled(&d->bus_master_enable_region,
(pci_get_word(d->config + PCI_COMMAND)
& PCI_COMMAND_MASTER) && d->has_power);
if (!d->has_power) {
pci_device_reset(d);
}
}
static const TypeInfo pci_device_type_info = {
.name = TYPE_PCI_DEVICE,
.parent = TYPE_DEVICE,

6
hw/pci/pci_host.c
View File

@ -74,7 +74,8 @@ void pci_host_config_write_common(PCIDevice *pci_dev, uint32_t addr,
/* non-zero functions are only exposed when function 0 is present,
* allowing direct removal of unexposed functions.
*/
if (pci_dev->qdev.hotplugged && !pci_get_function_0(pci_dev)) {
if ((pci_dev->qdev.hotplugged && !pci_get_function_0(pci_dev)) ||
!pci_dev->has_power) {
return;
}
@ -97,7 +98,8 @@ uint32_t pci_host_config_read_common(PCIDevice *pci_dev, uint32_t addr,
/* non-zero functions are only exposed when function 0 is present,
* allowing direct removal of unexposed functions.
*/
if (pci_dev->qdev.hotplugged && !pci_get_function_0(pci_dev)) {
if ((pci_dev->qdev.hotplugged && !pci_get_function_0(pci_dev)) ||
!pci_dev->has_power) {
return ~0x0;
}

2
include/hw/pci/pci.h
View File

@ -268,6 +268,7 @@ typedef struct PCIReqIDCache PCIReqIDCache;
struct PCIDevice {
DeviceState qdev;
bool partially_hotplugged;
bool has_power;
/* PCI config space */
uint8_t *config;
@ -908,5 +909,6 @@ extern const VMStateDescription vmstate_pci_device;
}
MSIMessage pci_get_msi_message(PCIDevice *dev, int vector);
void pci_set_power(PCIDevice *pci_dev, bool state);
#endif