Re: [Qemu-devel] [PATCH v3 2/2] intel_iommu: allow migration

[Peter Xu <peterx@redhat.com>]

On Fri, Jan 06, 2017 at 03:05:47PM +0800, Jason Wang wrote:
> 
> 
> On 2017年01月06日 12:06, Peter Xu wrote:
> >IOMMU needs to be migrated before all the PCI devices (in case there are
> >devices that will request for address translation). So marking it with a
> >priority higher than the default (which PCI devices and other belong).
> >Migration framework handled the rest.
> >
> >Signed-off-by: Peter Xu <peterx@redhat.com>
> >---
> >  hw/i386/intel_iommu.c       | 22 +++++++++++++++++++++-
> >  include/migration/vmstate.h |  1 +
> >  2 files changed, 22 insertions(+), 1 deletion(-)
> >
> >diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> >index 5f3e351..119217b 100644
> >--- a/hw/i386/intel_iommu.c
> >+++ b/hw/i386/intel_iommu.c
> >@@ -1996,7 +1996,27 @@ static void vtd_iommu_notify_flag_changed(MemoryRegion *iommu,
> >  static const VMStateDescription vtd_vmstate = {
> >      .name = "iommu-intel",
> >-    .unmigratable = 1,
> >+    .version_id = 1,
> >+    .minimum_version_id = 1,
> >+    .priority = MIG_PRI_IOMMU,
> >+    .fields = (VMStateField[]) {
> >+        VMSTATE_UINT64(root, IntelIOMMUState),
> >+        VMSTATE_UINT64(intr_root, IntelIOMMUState),
> >+        VMSTATE_UINT64(iq, IntelIOMMUState),
> >+        VMSTATE_UINT32(intr_size, IntelIOMMUState),
> >+        VMSTATE_UINT16(iq_head, IntelIOMMUState),
> >+        VMSTATE_UINT16(iq_tail, IntelIOMMUState),
> >+        VMSTATE_UINT16(iq_size, IntelIOMMUState),
> >+        VMSTATE_UINT16(next_frcd_reg, IntelIOMMUState),
> >+        VMSTATE_UINT8_ARRAY(csr, IntelIOMMUState, DMAR_REG_SIZE),
> 
> Do we need migrate wmask, w1cmask, womask too?

Should not. Although we are using arrays here, they should be only
configured during vtd_define_*() and should be constant values for the
whole lifecycle of the device (which is mostly decided by the spec).

Thanks,

-- peterx