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.
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 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
