Re: [Qemu-devel] [PATCH v2 2/2] ivshmem: use irqfd to interrupt among VMs

[liu ping fan]

On Thu, Nov 29, 2012 at 12:42 PM, Cam Macdonell <address@hidden> wrote:
> On Tue, Nov 27, 2012 at 7:53 PM, liu ping fan <address@hidden> wrote:
>> On Wed, Nov 28, 2012 at 5:48 AM, Cam Macdonell <address@hidden> wrote:
>>> On Sat, Nov 24, 2012 at 8:51 PM, Liu Ping Fan <address@hidden> wrote:
>>>> From: Liu Ping Fan <address@hidden>
>>>>
>>>> Using irqfd, so we can avoid switch between kernel and user when
>>>> VMs interrupts each other.
>>>
>>> Nice work.  Due to a hardware failure, there will be a small delay in
>>> me being able to test this.  I'll follow up as soon as I can.
>>>
>> BTW where can I find the latest guest code for test?
>> I got the guest code from git://gitorious.org/nahanni/guest-code.git.
>> But it seems outdated, after fixing the unlocked_ioctl, and vm-id bits
>> position (the codes conflict with ivshmem spec), it works (I have
>> tested for V1).
>
> Hello,
>
> Which device driver are you using?
>
guest-code/kernel_module/standard/kvm_ivshmem.c

> Cam
>
>>
>> Regards,
>> Pingfan
>>
>>>>
>>>> Signed-off-by: Liu Ping Fan <address@hidden>
>>>> ---
>>>>  hw/ivshmem.c |   54 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
>>>>  1 files changed, 53 insertions(+), 1 deletions(-)
>>>>
>>>> diff --git a/hw/ivshmem.c b/hw/ivshmem.c
>>>> index 7c8630c..5709e89 100644
>>>> --- a/hw/ivshmem.c
>>>> +++ b/hw/ivshmem.c
>>>> @@ -19,6 +19,7 @@
>>>>  #include "hw.h"
>>>>  #include "pc.h"
>>>>  #include "pci.h"
>>>> +#include "msi.h"
>>>>  #include "msix.h"
>>>>  #include "kvm.h"
>>>>  #include "migration.h"
>>>> @@ -83,6 +84,7 @@ typedef struct IVShmemState {
>>>>      uint32_t vectors;
>>>>      uint32_t features;
>>>>      EventfdEntry *eventfd_table;
>>>> +    int *vector_virqs;
>>>>
>>>>      Error *migration_blocker;
>>>>
>>>> @@ -625,16 +627,62 @@ static int ivshmem_load(QEMUFile* f, void *opaque, 
>>>> int version_id)
>>>>      return 0;
>>>>  }
>>>>
>>>> +static int ivshmem_vector_use(PCIDevice *dev, unsigned vector,
>>>> +                                     MSIMessage msg)
>>>> +{
>>>> +    IVShmemState *s = DO_UPCAST(IVShmemState, dev, dev);
>>>> +    int virq;
>>>> +    EventNotifier *n = &s->peers[s->vm_id].eventfds[vector];
>>>> +
>>>> +    virq = kvm_irqchip_add_msi_route(kvm_state, msg);
>>>> +    if (virq >= 0 && kvm_irqchip_add_irqfd_notifier(kvm_state, n, virq) 
>>>> >= 0) {
>>>> +        s->vector_virqs[vector] = virq;
>>>> +        qemu_chr_add_handlers(s->eventfd_chr[vector], NULL, NULL, NULL, 
>>>> NULL);
>>>> +    } else if (virq >= 0) {
>>>> +        kvm_irqchip_release_virq(kvm_state, virq);
>>>> +        error_report("ivshmem, can not setup irqfd\n");
>>>> +        return -1;
>>>> +    } else {
>>>> +        error_report("ivshmem, no enough msi route to setup irqfd\n");
>>>> +        return -1;
>>>> +    }
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static void ivshmem_vector_release(PCIDevice *dev, unsigned vector)
>>>> +{
>>>> +    IVShmemState *s = DO_UPCAST(IVShmemState, dev, dev);
>>>> +    EventNotifier *n = &s->peers[s->vm_id].eventfds[vector];
>>>> +    int virq = s->vector_virqs[vector];
>>>> +
>>>> +    if (s->vector_virqs[vector] >= 0) {
>>>> +        kvm_irqchip_remove_irqfd_notifier(kvm_state, n, virq);
>>>> +        kvm_irqchip_release_virq(kvm_state, virq);
>>>> +        s->vector_virqs[vector] = -1;
>>>> +    }
>>>> +}
>>>> +
>>>>  static void ivshmem_write_config(PCIDevice *pci_dev, uint32_t address,
>>>>                                  uint32_t val, int len)
>>>>  {
>>>> +    bool is_enabled, was_enabled = msi_enabled(pci_dev);
>>>> +
>>>>      pci_default_write_config(pci_dev, address, val, len);
>>>> +    is_enabled = msi_enabled(pci_dev);
>>>> +    if (!was_enabled && is_enabled) {
>>>> +        msix_set_vector_notifiers(pci_dev, ivshmem_vector_use,
>>>> +            ivshmem_vector_release);
>>>> +    } else if (was_enabled && !is_enabled) {
>>>> +        msix_unset_vector_notifiers(pci_dev);
>>>> +    }
>>>>  }
>>>>
>>>>  static int pci_ivshmem_init(PCIDevice *dev)
>>>>  {
>>>>      IVShmemState *s = DO_UPCAST(IVShmemState, dev, dev);
>>>>      uint8_t *pci_conf;
>>>> +    int i;
>>>>
>>>>      if (s->sizearg == NULL)
>>>>          s->ivshmem_size = 4 << 20; /* 4 MB default */
>>>> @@ -758,7 +806,10 @@ static int pci_ivshmem_init(PCIDevice *dev)
>>>>      }
>>>>
>>>>      s->dev.config_write = ivshmem_write_config;
>>>> -
>>>> +    s->vector_virqs = g_new0(int, s->vectors);
>>>> +    for (i = 0; i < s->vectors; i++) {
>>>> +        s->vector_virqs[i] = -1;
>>>> +    }
>>>>      return 0;
>>>>  }
>>>>
>>>> @@ -770,6 +821,7 @@ static void pci_ivshmem_uninit(PCIDevice *dev)
>>>>          migrate_del_blocker(s->migration_blocker);
>>>>          error_free(s->migration_blocker);
>>>>      }
>>>> +    g_free(s->vector_virqs);
>>>>
>>>>      memory_region_destroy(&s->ivshmem_mmio);
>>>>      memory_region_del_subregion(&s->bar, &s->ivshmem);
>>>> --
>>>> 1.7.4.4
>>>>
>>