On Sun, 26 Jan 2014 12:37:09 +0200
"Michael S. Tsirkin" <m...@redhat.com> wrote:
> 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 <m...@redhat.com>
> ---
> hw/acpi/pcihp.c | 21 +++++----------------
> include/hw/acpi/pcihp.h | 2 +-
> 2 files changed, 6 insertions(+), 17 deletions(-)
>
> diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c
> index 3fa3d7c..4345f5d 100644
> --- a/hw/acpi/pcihp.c
> +++ b/hw/acpi/pcihp.c
> @@ -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:
> diff --git a/include/hw/acpi/pcihp.h b/include/hw/acpi/pcihp.h
> index 6230e60..aa297c2 100644
> --- a/include/hw/acpi/pcihp.h
> +++ b/include/hw/acpi/pcihp.h
> @@ -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;
After patch field AcpiPciHpPciStatus.device_present seem to be unused,
should it be deleted here as well?
