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

[Cam Macdonell <cam@cs.ualberta.ca>]

On Tue, Dec 4, 2012 at 4:10 AM, Andrew Jones <drjones@redhat.com> wrote:
>
>
> ----- Original Message -----
>> On Thu, Nov 29, 2012 at 1:34 AM, liu ping fan <qemulist@gmail.com>
>> wrote:
>> > On Thu, Nov 29, 2012 at 12:42 PM, Cam Macdonell
>> > <cam@cs.ualberta.ca> wrote:
>> >> On Tue, Nov 27, 2012 at 7:53 PM, liu ping fan <qemulist@gmail.com>
>> >> wrote:
>> >>> On Wed, Nov 28, 2012 at 5:48 AM, Cam Macdonell
>> >>> <cam@cs.ualberta.ca> wrote:
>> >>>> On Sat, Nov 24, 2012 at 8:51 PM, Liu Ping Fan
>> >>>> <qemulist@gmail.com> wrote:
>> >>>>> From: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
>> >>>>>
>> >>>>> 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 But it seems outdated, after fixing the unlocked_ioctl, and vm-id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
>>
>> The uio driver is the recommended one, however if you want to use the
>> kvm_ivshmem one and have it working, then feel free to continue.
>
> If the uio driver is the recommended one, then can you please post it
> to lkml? It should be integrated into drivers/virt with an appropriate
> Kconfig update.
>

Sure.  Should it go under drivers/virt or drivers/uio?  It seems the
uio drivers all get grouped together.

Thanks,
Cam

> Thanks,
> Drew
>
>>
>> I had deleted it form the repo, but some users had based solutions
>> off
>> it, so I added it back.
>>
>> btw, my hardware issue has been resolved, so I'll get to testing your
>> patch soon.
>>
>> Sincerely,
>> Cam
>>
>> >
>> >> Cam
>> >>
>> >>>
>> >>> Regards,
>> >>> Pingfan
>> >>>
>> >>>>>
>> >>>>> Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
>> >>>>> ---
>> >>>>>  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
>> >>>>>
>> >>>
>> >
>>
>>
>