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pcihp: reduce number of device check events 

PIIX created a made-up value for the UP register since it was read by
guest 32 times for each interrupt.
There's no reason to do this for the new PCIHP: register is only read
once for each interrupt, so clean up code by making read act as an
interrupt acknowledgement: the new UP register clear on read.

In this way we cut down the number of bus rescans
by a factor of 32, and drop a bunch of code that's
now unused.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Michael S. Tsirkin 2014-01-26 12:31:27 +02:00
parent 2b2449f7e4
commit 5a2223ca26
2 changed files with 6 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
hw/acpi/pcihp.c
View File

@ -116,7 +116,6 @@ static void acpi_pcihp_eject_slot(AcpiPciHpState *s, unsigned bsel, unsigned slo
{
BusChild *kid, *next;
int slot = ffs(slots) - 1;
bool slot_free = true;
PCIBus *bus = acpi_pcihp_find_hotplug_bus(s, bsel);
if (!bus) {
@ -125,21 +124,17 @@ static void acpi_pcihp_eject_slot(AcpiPciHpState *s, unsigned bsel, unsigned slo
/* Mark request as complete */
s->acpi_pcihp_pci_status[bsel].down &= ~(1U << slot);
s->acpi_pcihp_pci_status[bsel].up &= ~(1U << slot);
QTAILQ_FOREACH_SAFE(kid, &bus->qbus.children, sibling, next) {
DeviceState *qdev = kid->child;
PCIDevice *dev = PCI_DEVICE(qdev);
if (PCI_SLOT(dev->devfn) == slot) {
if (acpi_pcihp_pc_no_hotplug(s, dev)) {
slot_free = false;
} else {
if (!acpi_pcihp_pc_no_hotplug(s, dev)) {
object_unparent(OBJECT(qdev));
}
}
}
if (slot_free) {
s->acpi_pcihp_pci_status[bsel].device_present &= ~(1U << slot);
}
}
static void acpi_pcihp_update_hotplug_bus(AcpiPciHpState *s, int bsel)
@ -153,7 +148,6 @@ static void acpi_pcihp_update_hotplug_bus(AcpiPciHpState *s, int bsel)
}
s->acpi_pcihp_pci_status[bsel].hotplug_enable = ~0;
s->acpi_pcihp_pci_status[bsel].device_present = 0;
if (!bus) {
return;
@ -166,8 +160,6 @@ static void acpi_pcihp_update_hotplug_bus(AcpiPciHpState *s, int bsel)
if (acpi_pcihp_pc_no_hotplug(s, pdev)) {
s->acpi_pcihp_pci_status[bsel].hotplug_enable &= ~(1U << slot);
}
s->acpi_pcihp_pci_status[bsel].device_present |= (1U << slot);
}
}
@ -187,7 +179,7 @@ void acpi_pcihp_reset(AcpiPciHpState *s)
static void enable_device(AcpiPciHpState *s, unsigned bsel, int slot)
{
s->acpi_pcihp_pci_status[bsel].device_present |= (1U << slot);
s->acpi_pcihp_pci_status[bsel].up |= (1U << slot);
}
static void disable_device(AcpiPciHpState *s, unsigned bsel, int slot)
@ -208,7 +200,6 @@ int acpi_pcihp_device_hotplug(AcpiPciHpState *s, PCIDevice *dev,
* it is present on boot, no hotplug event is necessary. We do send an
* event when the device is disabled later. */
if (state == PCI_COLDPLUG_ENABLED) {
s->acpi_pcihp_pci_status[bsel].device_present |= (1U << slot);
return 0;
}
@ -233,10 +224,8 @@ static uint64_t pci_read(void *opaque, hwaddr addr, unsigned int size)
switch (addr) {
case PCI_UP_BASE - PCI_HOTPLUG_ADDR:
/* Manufacture an "up" value to cause a device check on any hotplug
* slot with a device. Extra device checks are harmless. */
val = s->acpi_pcihp_pci_status[bsel].device_present &
s->acpi_pcihp_pci_status[bsel].hotplug_enable;
val = s->acpi_pcihp_pci_status[bsel].up;
s->acpi_pcihp_pci_status[bsel].up = 0;
ACPI_PCIHP_DPRINTF("pci_up_read %" PRIu32 "\n", val);
break;
case PCI_DOWN_BASE - PCI_HOTPLUG_ADDR:

2
include/hw/acpi/pcihp.h
View File

@ -32,7 +32,7 @@
#include "hw/pci/pci.h" /* for PCIHotplugState */
typedef struct AcpiPciHpPciStatus {
uint32_t up; /* deprecated, maintained for migration compatibility */
uint32_t up;
uint32_t down;
uint32_t hotplug_enable;
uint32_t device_present;