Re: [Qemu-devel] [PATCH v3 24/26] q35: add acpi-based pci hotplug.

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Oct 19, 2012 at 04:43:41PM -0400, Jason Baron wrote:
> From: Jason Baron <jbaron@redhat.com>
> 
> Add piix style acpi hotplug to q35.

piix style is an understatement. This is exactly the same
interface probably to enable the same bios code to
run on both piix and q35.

If true let's not duplicate code: please factor relevant
functionality out of piix and reuse.
You might be able to reuse migration support as well:
it seems broken currently so this needs a TODO.

> Signed-off-by: Jason Baron <jbaron@redhat.com>
> ---
>  hw/acpi_ich9.c |  172 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>  hw/acpi_ich9.h |   10 +++
>  2 files changed, 181 insertions(+), 1 deletions(-)
> 
> diff --git a/hw/acpi_ich9.c b/hw/acpi_ich9.c
> index 61034d3..d5f25c9 100644
> --- a/hw/acpi_ich9.c
> +++ b/hw/acpi_ich9.c
> @@ -41,6 +41,13 @@ do { printf("%s "fmt, __func__, ## __VA_ARGS__); } while (0)
>  #define ICH9_DEBUG(fmt, ...)    do { } while (0)
>  #endif
>  
> +#define PCI_UP_BASE 0xae00
> +#define PCI_DOWN_BASE 0xae04
> +#define PCI_EJ_BASE 0xae08
> +#define PCI_RMV_BASE 0xae0c
> +#define ICH9_PCI_HOTPLUG_STATUS 2
> +
> +
>  static void pm_ioport_write_fallback(void *opaque, uint32_t addr, int len,
>                                       uint32_t val);
>  static uint32_t pm_ioport_read_fallback(void *opaque, uint32_t addr, int len);
> @@ -55,7 +62,10 @@ static void pm_update_sci(ICH9LPCPMRegs *pm)
>                    (ACPI_BITMASK_RT_CLOCK_ENABLE |
>                     ACPI_BITMASK_POWER_BUTTON_ENABLE |
>                     ACPI_BITMASK_GLOBAL_LOCK_ENABLE |
> -                   ACPI_BITMASK_TIMER_ENABLE)) != 0);
> +                   ACPI_BITMASK_TIMER_ENABLE)) != 0) ||
> +         (((pm->acpi_regs.gpe.sts[0] & pm->acpi_regs.gpe.en[0])
> +          & ICH9_PCI_HOTPLUG_STATUS) != 0);
> +
>      qemu_set_irq(pm->irq, sci_level);
>  
>      /* schedule a timer interruption if needed */
> @@ -77,6 +87,7 @@ static void pm_ioport_writeb(void *opaque, uint32_t addr, uint32_t val)
>      switch (addr & ICH9_PMIO_MASK) {
>      case ICH9_PMIO_GPE0_STS ... (ICH9_PMIO_GPE0_STS + ICH9_PMIO_GPE0_LEN - 1):
>          acpi_gpe_ioport_writeb(&pm->acpi_regs, addr, val);
> +        pm_update_sci(pm);
>          break;
>      default:
>          break;
> @@ -283,6 +294,65 @@ const VMStateDescription vmstate_ich9_pm = {
>      }
>  };
>  
> +static void acpi_ich9_eject_slot(ICH9LPCPMRegs *opaque, unsigned slots)
> +{
> +    BusChild *kid, *next;
> +    ICH9LPCPMRegs *pm = opaque;
> +    ICH9LPCState *lpc = container_of(pm, ICH9LPCState, pm);
> +    PCIDevice *s = PCI_DEVICE(lpc);
> +    BusState *bus = qdev_get_parent_bus(&s->qdev);
> +    int slot = ffs(slots) - 1;
> +    bool slot_free = true;
> +
> +    /* Mark request as complete */
> +    pm->pci0_status.down &= ~(1U << slot);
> +
> +    QTAILQ_FOREACH_SAFE(kid, &bus->children, sibling, next) {
> +        DeviceState *qdev = kid->child;
> +        PCIDevice *dev = PCI_DEVICE(qdev);
> +        PCIDeviceClass *pc = PCI_DEVICE_GET_CLASS(dev);
> +        if (PCI_SLOT(dev->devfn) == slot) {
> +            if (pc->no_hotplug) {
> +                slot_free = false;
> +            } else {
> +                qdev_free(qdev);
> +            }
> +        }
> +    }
> +    if (slot_free) {
> +        pm->pci0_slot_device_present &= ~(1U << slot);
> +    }
> +}
> +
> +static void acpi_ich9_update_hotplug(ICH9LPCPMRegs *pm)
> +{
> +    ICH9LPCState *lpc = container_of(pm, ICH9LPCState, pm);
> +    PCIDevice *dev = PCI_DEVICE(lpc);
> +    BusState *bus = qdev_get_parent_bus(&dev->qdev);
> +    BusChild *kid, *next;
> +
> +    /* Execute any pending removes during reset */
> +    while (pm->pci0_status.down) {
> +        acpi_ich9_eject_slot(pm, pm->pci0_status.down);
> +    }
> +
> +    pm->pci0_hotplug_enable = ~0;
> +    pm->pci0_slot_device_present = 0;
> +
> +    QTAILQ_FOREACH_SAFE(kid, &bus->children, sibling, next) {
> +        DeviceState *qdev = kid->child;
> +        PCIDevice *pdev = PCI_DEVICE(qdev);
> +        PCIDeviceClass *pc = PCI_DEVICE_GET_CLASS(pdev);
> +        int slot = PCI_SLOT(pdev->devfn);
> +
> +        if (pc->no_hotplug) {
> +            pm->pci0_hotplug_enable &= ~(1U << slot);
> +        }
> +
> +        pm->pci0_slot_device_present |= (1U << slot);
> +    }
> +}
> +
>  static void pm_reset(void *opaque)
>  {
>      ICH9LPCPMRegs *pm = opaque;
> @@ -300,6 +370,7 @@ static void pm_reset(void *opaque)
>      }
>  
>      pm_update_sci(pm);
> +    acpi_ich9_update_hotplug(pm);
>  }
>  
>  static void pm_powerdown_req(Notifier *n, void *opaque)
> @@ -309,6 +380,104 @@ static void pm_powerdown_req(Notifier *n, void *opaque)
>      acpi_pm1_evt_power_down(&pm->acpi_regs);
>  }
>  
> +static uint32_t pci_up_read(void *opaque, uint32_t addr)
> +{
> +    ICH9LPCPMRegs *pm = opaque;
> +    uint32_t val;
> +
> +    /* Manufacture an "up" value to cause a device check on any hotplug
> +     * slot with a device.  Extra device checks are harmless. */
> +    val = pm->pci0_slot_device_present & pm->pci0_hotplug_enable;
> +
> +    ICH9_DEBUG("pci_up_read %x\n", val);
> +    return val;
> +}
> +
> +static uint32_t pci_down_read(void *opaque, uint32_t addr)
> +{
> +    ICH9LPCPMRegs *pm = opaque;
> +    uint32_t val = pm->pci0_status.down;
> +
> +    ICH9_DEBUG("pci_down_read %x\n", val);
> +    return val;
> +}
> +
> +static uint32_t pci_features_read(void *opaque, uint32_t addr)
> +{
> +    /* No feature defined yet */
> +    ICH9_DEBUG("pci_features_read %x\n", 0);
> +    return 0;
> +}
> +
> +static void pciej_write(void *opaque, uint32_t addr, uint32_t val)
> +{
> +    acpi_ich9_eject_slot(opaque, val);
> +
> +    ICH9_DEBUG("pciej write %x <== %d\n", addr, val);
> +}
> +
> +static uint32_t pcirmv_read(void *opaque, uint32_t addr)
> +{
> +    ICH9LPCPMRegs *pm = opaque;
> +
> +    return pm->pci0_hotplug_enable;
> +}
> +
> +static void enable_device(ICH9LPCPMRegs *pm, int slot)
> +{
> +    pm->acpi_regs.gpe.sts[0] |= ICH9_PCI_HOTPLUG_STATUS;
> +    pm->pci0_slot_device_present |= (1U << slot);
> +}
> +
> +static void disable_device(ICH9LPCPMRegs *pm, int slot)
> +{
> +    pm->acpi_regs.gpe.sts[0] |= ICH9_PCI_HOTPLUG_STATUS;
> +    pm->pci0_status.down |= (1U << slot);
> +}
> +
> +static int ich9_device_hotplug(DeviceState *qdev, PCIDevice *dev,
> +                PCIHotplugState state)
> +{
> +    int slot = PCI_SLOT(dev->devfn);
> +    ICH9LPCState *lpc = DO_UPCAST(ICH9LPCState, d,
> +                                PCI_DEVICE(qdev));
> +    ICH9LPCPMRegs *pm = &lpc->pm;
> +
> +    /* Don't send event when device is enabled during qemu machine creation:
> +     * 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) {
> +        pm->pci0_slot_device_present |= (1U << slot);
> +        return 0;
> +    }
> +
> +    if (state == PCI_HOTPLUG_ENABLED) {
> +        enable_device(pm, slot);
> +    } else {
> +        disable_device(pm, slot);
> +    }
> +
> +    pm_update_sci(pm);
> +
> +    return 0;
> +}
> +
> +static void ich9_acpi_system_hot_add_init(ICH9LPCPMRegs *s)
> +{
> +    ICH9LPCState *lpc = container_of(s, ICH9LPCState, pm);
> +    PCIDevice *pdev = PCI_DEVICE(lpc);
> +
> +    register_ioport_read(PCI_UP_BASE, 4, 4, pci_up_read, s);
> +    register_ioport_read(PCI_DOWN_BASE, 4, 4, pci_down_read, s);
> +
> +    register_ioport_write(PCI_EJ_BASE, 4, 4, pciej_write, s);
> +    register_ioport_read(PCI_EJ_BASE, 4, 4,  pci_features_read, s);
> +
> +    register_ioport_read(PCI_RMV_BASE, 4, 4,  pcirmv_read, s);
> +
> +    pci_bus_hotplug(pdev->bus, ich9_device_hotplug, &pdev->qdev);
> +}
> +
>  void ich9_pm_init(ICH9LPCPMRegs *pm, qemu_irq sci_irq, qemu_irq cmos_s3)
>  {
>      acpi_pm_tmr_init(&pm->acpi_regs, ich9_pm_update_sci_fn);
> @@ -319,4 +488,5 @@ void ich9_pm_init(ICH9LPCPMRegs *pm, qemu_irq sci_irq, qemu_irq cmos_s3)
>      qemu_register_reset(pm_reset, pm);
>      pm->powerdown_notifier.notify = pm_powerdown_req;
>      qemu_register_powerdown_notifier(&pm->powerdown_notifier);
> +    ich9_acpi_system_hot_add_init(pm);
>  }
> diff --git a/hw/acpi_ich9.h b/hw/acpi_ich9.h
> index 180c406..b4e2aff 100644
> --- a/hw/acpi_ich9.h
> +++ b/hw/acpi_ich9.h
> @@ -23,6 +23,11 @@
>  
>  #include "acpi.h"
>  
> +struct pci_status {
> +    uint32_t up; /* deprecated, maintained for migration compatibility */
> +    uint32_t down;
> +};
> +
>  typedef struct ICH9LPCPMRegs {
>      /*
>       * In ich9 spec says that pm1_cnt register is 32bit width and
> @@ -37,6 +42,11 @@ typedef struct ICH9LPCPMRegs {
>  
>      uint32_t pm_io_base;
>      Notifier powerdown_notifier;
> +
> +    /* for pci hotplug */
> +    struct pci_status pci0_status;
> +    uint32_t pci0_hotplug_enable;
> +    uint32_t pci0_slot_device_present;
>  } ICH9LPCPMRegs;
>  
>  void ich9_pm_init(ICH9LPCPMRegs *pm,
> -- 
> 1.7.1