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

[Andrew Jones <drjones@redhat.com>]

----- 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 But it seems outdated, after fixing the unlocked_ioctl, and vm-id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.

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
> >>>>>
> >>>
> >
> 
>