On Fri, Jun 21, 2013 at 12:08:58AM +1000, Alexey Kardashevskiy wrote:
> At the moment QEMU creates a route for every MSI IRQ.
>
> Now we are about to add IRQFD support on PPC64-pseries platform.
> pSeries already has in-kernel emulated interrupt controller with
> 8192 IRQs. Also, pSeries PHB already supports MSIMessage to IRQ
> mapping as a part of PAPR requirements for MSI/MSIX guests.
> Specifically, the pSeries guest does not touch MSIMessage's at
> all, instead it uses rtas_ibm_change_msi and rtas_ibm_query_interrupt_source
> rtas calls to do the mapping.
>
> Therefore we do not really need more routing than we got already.
> The patch introduces the infrastructure to enable direct IRQ mapping.
>
> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
>
> ---
>
> The patch is raw and ugly indeed, I made it only to demonstrate
> the idea and see if it has right to live or not.
>
> For some reason which I do not really understand (limited GSI numbers?)
> the existing code always adds routing and I do not see why we would need it.
>
> Thanks!
> ---
> hw/misc/vfio.c | 11 +++++++++--
> hw/pci/pci.c | 13 +++++++++++++
> hw/ppc/spapr_pci.c | 13 +++++++++++++
> hw/virtio/virtio-pci.c | 26 ++++++++++++++++++++------
> include/hw/pci/pci.h | 4 ++++
> include/hw/pci/pci_bus.h | 1 +
> 6 files changed, 60 insertions(+), 8 deletions(-)
>
> diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
> index 14aac04..2d9eef7 100644
> --- a/hw/misc/vfio.c
> +++ b/hw/misc/vfio.c
> @@ -639,7 +639,11 @@ static int vfio_msix_vector_do_use(PCIDevice *pdev,
> unsigned int nr,
> * Attempt to enable route through KVM irqchip,
> * default to userspace handling if unavailable.
> */
> - vector->virq = msg ? kvm_irqchip_add_msi_route(kvm_state, *msg) : -1;
> +
> + vector->virq = msg ? pci_bus_map_msi(vdev->pdev.bus, *msg) : -1;
> + if (vector->virq < 0) {
> + vector->virq = msg ? kvm_irqchip_add_msi_route(kvm_state, *msg) : -1;
> + }
> if (vector->virq < 0 ||
> kvm_irqchip_add_irqfd_notifier(kvm_state, &vector->interrupt,
> vector->virq) < 0) {
> @@ -807,7 +811,10 @@ retry:
> * Attempt to enable route through KVM irqchip,
> * default to userspace handling if unavailable.
> */
> - vector->virq = kvm_irqchip_add_msi_route(kvm_state, msg);
> + vector->virq = pci_bus_map_msi(vdev->pdev.bus, msg);
> + if (vector->virq < 0) {
> + vector->virq = kvm_irqchip_add_msi_route(kvm_state, msg);
> + }
> if (vector->virq < 0 ||
> kvm_irqchip_add_irqfd_notifier(kvm_state, &vector->interrupt,
> vector->virq) < 0) {
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index a976e46..a9875e9 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -1254,6 +1254,19 @@ void pci_device_set_intx_routing_notifier(PCIDevice
> *dev,
> dev->intx_routing_notifier = notifier;
> }
>
> +void pci_bus_set_map_msi_fn(PCIBus *bus, pci_map_msi_fn map_msi_fn)
> +{
> + bus->map_msi = map_msi_fn;
> +}
> +
> +int pci_bus_map_msi(PCIBus *bus, MSIMessage msg)
> +{
> + if (bus->map_msi) {
> + return bus->map_msi(bus, msg);
> + }
> + return -1;
> +}
> +
> /*
> * PCI-to-PCI bridge specification
> * 9.1: Interrupt routing. Table 9-1
> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
> index 80408c9..9ef9a29 100644
> --- a/hw/ppc/spapr_pci.c
> +++ b/hw/ppc/spapr_pci.c
> @@ -500,6 +500,18 @@ static void spapr_msi_write(void *opaque, hwaddr addr,
> qemu_irq_pulse(xics_get_qirq(spapr->icp, irq));
> }
>
> +static int spapr_msi_get_irq(PCIBus *bus, MSIMessage msg)
> +{
> + DeviceState *par = bus->qbus.parent;
> + sPAPRPHBState *sphb = (sPAPRPHBState *) par;
> + unsigned long addr = msg.address - sphb->msi_win_addr;
> + int ndev = addr >> 16;
> + int vec = ((addr & 0xFFFF) >> 2) | msg.data;
> + uint32_t irq = sphb->msi_table[ndev].irq + vec;
This array seems to be SPAPR_MSIX_MAX_DEVS in size, no?
Won't this overflow if ndev is large?
> +
> + return (int)irq;
> +}
> +
> static const MemoryRegionOps spapr_msi_ops = {
> /* There is no .read as the read result is undefined by PCI spec */
> .read = NULL,
> @@ -664,6 +676,7 @@ static int _spapr_phb_init(SysBusDevice *s)
>
> sphb->lsi_table[i].irq = irq;
> }
> + pci_bus_set_map_msi_fn(bus, spapr_msi_get_irq);
>
> return 0;
> }
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index d309416..587f53e 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -472,6 +472,8 @@ static unsigned virtio_pci_get_features(DeviceState *d)
> return proxy->host_features;
> }
>
> +extern int spapr_msi_get_irq(PCIBus *bus, MSIMessage *msg);
> +
> static int kvm_virtio_pci_vq_vector_use(VirtIOPCIProxy *proxy,
> unsigned int queue_no,
> unsigned int vector,
> @@ -481,7 +483,10 @@ static int kvm_virtio_pci_vq_vector_use(VirtIOPCIProxy
> *proxy,
> int ret;
>
> if (irqfd->users == 0) {
> - ret = kvm_irqchip_add_msi_route(kvm_state, msg);
> + ret = pci_bus_map_msi(proxy->pci_dev.bus, msg);
> + if (ret < 0) {
> + ret = kvm_irqchip_add_msi_route(kvm_state, msg);
> + }
> if (ret < 0) {
> return ret;
> }
> @@ -609,14 +614,23 @@ static int virtio_pci_vq_vector_unmask(VirtIOPCIProxy
> *proxy,
> VirtQueue *vq = virtio_get_queue(proxy->vdev, queue_no);
> EventNotifier *n = virtio_queue_get_guest_notifier(vq);
> VirtIOIRQFD *irqfd;
> - int ret = 0;
> + int ret = 0, tmp;
>
> if (proxy->vector_irqfd) {
> irqfd = &proxy->vector_irqfd[vector];
> - if (irqfd->msg.data != msg.data || irqfd->msg.address !=
> msg.address) {
> - ret = kvm_irqchip_update_msi_route(kvm_state, irqfd->virq, msg);
> - if (ret < 0) {
> - return ret;
> +
> + tmp = pci_bus_map_msi(proxy->pci_dev.bus, msg);
> + if (tmp >= 0) {
> + if (irqfd->virq != tmp) {
> + fprintf(stderr, "FIXME: MSI(-X) vector has changed from %X
> to %x\n",
> + irqfd->virq, tmp);
> + }
> + } else {
> + if (irqfd->msg.data != msg.data || irqfd->msg.address !=
> msg.address) {
> + ret = kvm_irqchip_update_msi_route(kvm_state, irqfd->virq,
> msg);
> + if (ret < 0) {
> + return ret;
> + }
> }
> }
> }
> diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
> index 8797802..632739a 100644
> --- a/include/hw/pci/pci.h
> +++ b/include/hw/pci/pci.h
> @@ -332,6 +332,7 @@ MemoryRegion *pci_address_space_io(PCIDevice *dev);
> typedef void (*pci_set_irq_fn)(void *opaque, int irq_num, int level);
> typedef int (*pci_map_irq_fn)(PCIDevice *pci_dev, int irq_num);
> typedef PCIINTxRoute (*pci_route_irq_fn)(void *opaque, int pin);
> +typedef int (*pci_map_msi_fn)(PCIBus *bus, MSIMessage msg);
>
> typedef enum {
> PCI_HOTPLUG_DISABLED,
> @@ -375,6 +376,9 @@ bool pci_intx_route_changed(PCIINTxRoute *old,
> PCIINTxRoute *new);
> void pci_bus_fire_intx_routing_notifier(PCIBus *bus);
> void pci_device_set_intx_routing_notifier(PCIDevice *dev,
> PCIINTxRoutingNotifier notifier);
> +void pci_bus_set_map_msi_fn(PCIBus *bus, pci_map_msi_fn map_msi_fn);
> +int pci_bus_map_msi(PCIBus *bus, MSIMessage msg);
> +
> void pci_device_reset(PCIDevice *dev);
> void pci_bus_reset(PCIBus *bus);
>
> diff --git a/include/hw/pci/pci_bus.h b/include/hw/pci/pci_bus.h
> index 66762f6..81efd2b 100644
> --- a/include/hw/pci/pci_bus.h
> +++ b/include/hw/pci/pci_bus.h
> @@ -16,6 +16,7 @@ struct PCIBus {
> pci_set_irq_fn set_irq;
> pci_map_irq_fn map_irq;
> pci_route_irq_fn route_intx_to_irq;
> + pci_map_msi_fn map_msi;
> pci_hotplug_fn hotplug;
> DeviceState *hotplug_qdev;
> void *irq_opaque;
> --
> 1.7.10.4
