On Mon, Jan 31, 2011 at 03:09:09PM +0200, Avi Kivity wrote:
> On 01/30/2011 06:38 AM, Sheng Yang wrote:
> >(Sorry, missed this mail...)
> >
> >On Mon, Jan 17, 2011 at 02:29:44PM +0200, Avi Kivity wrote:
> >> On 01/06/2011 12:19 PM, Sheng Yang wrote:
> >> >Then we can support mask bit operation of assigned devices now.
> >> >
> >> >
> >> >
> >> >+int kvm_assigned_device_update_msix_mask_bit(struct kvm *kvm,
> >> >+ int assigned_dev_id, int entry, bool
> >> mask)
> >> >+{
> >> >+ int r = -EFAULT;
> >> >+ struct kvm_assigned_dev_kernel *adev;
> >> >+ int i;
> >> >+
> >> >+ if (!irqchip_in_kernel(kvm))
> >> >+ return r;
> >> >+
> >> >+ mutex_lock(&kvm->lock);
> >> >+ adev = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
> >> >+ assigned_dev_id);
> >> >+ if (!adev)
> >> >+ goto out;
> >> >+
> >> >+ for (i = 0; i< adev->entries_nr; i++)
> >> >+ if (adev->host_msix_entries[i].entry == entry) {
> >> >+ if (mask)
> >> >+ disable_irq_nosync(
> >> >+
> >> adev->host_msix_entries[i].vector);
> >>
> >> Is it okay to call disable_irq_nosync() here? IIRC we don't check
> >> the mask bit on irq delivery, so we may forward an interrupt to the
> >> guest after the mask bit was set.
> >>
> >> What does pci say about the mask bit? when does it take effect?
> >>
> >> Another question is whether disable_irq_nosync() actually programs
> >> the device mask bit, or not. If it does, then it's slow, and it may
> >> be better to leave interrupts enabled but have an internal pending
> >> bit. If it doesn't program the mask bit, it's fine.
> >
> >I think Michael and Jan had explained this.
> >>
> >> >+ else
> >> >+
> >> enable_irq(adev->host_msix_entries[i].vector);
> >> >+ r = 0;
> >> >+ break;
> >> >+ }
> >> >+out:
> >> >+ mutex_unlock(&kvm->lock);
> >> >+ return r;
> >> >+}
> >> >
> >> >+
> >> >+static int msix_table_mmio_read(struct kvm_io_device *this, gpa_t addr,
> >> int len,
> >> >+ void *val)
> >> >+{
> >> >+ struct kvm_msix_mmio_dev *mmio_dev =
> >> >+ container_of(this, struct kvm_msix_mmio_dev, table_dev);
> >> >+ struct kvm_msix_mmio *mmio;
> >> >+ int idx, ret = 0, entry, offset, r;
> >> >+
> >> >+ mutex_lock(&mmio_dev->lock);
> >> >+ idx = get_mmio_table_index(mmio_dev, addr, len);
> >> >+ if (idx< 0) {
> >> >+ ret = -EOPNOTSUPP;
> >> >+ goto out;
> >> >+ }
> >> >+ if ((addr& 0x3) || (len != 4&& len != 8))
> >> >+ goto out;
> >> >+
> >> >+ offset = addr& 0xf;
> >> >+ if (offset == PCI_MSIX_ENTRY_VECTOR_CTRL&& len == 8)
> >> >+ goto out;
> >> >+
> >> >+ mmio =&mmio_dev->mmio[idx];
> >> >+ entry = (addr - mmio->table_base_addr) / PCI_MSIX_ENTRY_SIZE;
> >> >+ r = copy_from_user(val, (void __user *)(mmio->table_base_va +
> >> >+ entry * PCI_MSIX_ENTRY_SIZE + offset), len);
> >> >+ if (r)
> >> >+ goto out;
> >>
> >> and return ret == 0?
> >
> >Yes. This operation should be handled by in-kernel MSI-X MMIO. So we return 0
> >in order to omit this action. We can add warning to it later.
>
> But it failed. We need to return -EFAULT.
So it would return to QEmu. OK, let QEmu prints warning about it.
--
regards
Yang, Sheng
>
> >The same as above.
> >>
> >> >+
> >> >+ if ((offset< PCI_MSIX_ENTRY_VECTOR_CTRL&& len == 4) ||
> >> >+ (offset< PCI_MSIX_ENTRY_DATA&& len == 8))
> >> >+ ret = -ENOTSYNC;
> >>
> >> goto out?
> >
> >No. This judgement only check if MSI data/address was touched. And the line
> >below would check if we need to operate mask bit. Because in theory guest can
> >use len=8 to modify MSI-X data and ctrl at the same time.
> >
>
> Ok, makes sense.
>
> --
> error compiling committee.c: too many arguments to function
>
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