Re: [Qemu-devel] [PATCH RFC v4 16/20] intel_iommu: do replay when context invalidate

[Peter Xu <peterx@redhat.com>]

On Wed, Jan 25, 2017 at 11:09:39AM +0800, Jason Wang wrote:
> 
> 
> On 2017年01月24日 12:52, Peter Xu wrote:
> >On Mon, Jan 23, 2017 at 06:36:17PM +0800, Jason Wang wrote:
> >>
> >>On 2017年01月20日 21:08, Peter Xu wrote:
> >>>Before this one we only invalidate context cache when we receive context
> >>>entry invalidations. However it's possible that the invalidation also
> >>>contains a domain switch (only if cache-mode is enabled for vIOMMU). In
> >>>that case we need to notify all the registered components about the new
> >>>mapping.
> >>>
> >>>Signed-off-by: Peter Xu <peterx@redhat.com>
> >>>---
> >>>  hw/i386/intel_iommu.c | 10 ++++++++++
> >>>  1 file changed, 10 insertions(+)
> >>>
> >>>diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> >>>index f9c5142..4b08b4d 100644
> >>>--- a/hw/i386/intel_iommu.c
> >>>+++ b/hw/i386/intel_iommu.c
> >>>@@ -1146,6 +1146,16 @@ static void vtd_context_device_invalidate(IntelIOMMUState *s,
> >>>                  trace_vtd_inv_desc_cc_device(bus_n, VTD_PCI_SLOT(devfn_it),
> >>>                                               VTD_PCI_FUNC(devfn_it));
> >>>                  vtd_as->context_cache_entry.context_cache_gen = 0;
> >>>+                /*
> >>>+                 * So a device is moving out of (or moving into) a
> >>>+                 * domain, a replay() suites here to notify all the
> >>>+                 * IOMMU_NOTIFIER_MAP registers about this change.
> >>>+                 * This won't bring bad even if we have no such
> >>>+                 * notifier registered - the IOMMU notification
> >>>+                 * framework will skip MAP notifications if that
> >>>+                 * happened.
> >>>+                 */
> >>>+                memory_region_iommu_replay_all(&vtd_as->iommu);
> >>DSI and GLOBAL questions come back again or no need to care about them :) ?
> >DSI/GLOBAL hanldings are in patch 20 (though it'll be squashed into 18
> >in my next post). Is that what you mean above?
> 
> Seems not, I mean DSI/GLOBAL for context cache invalidation instead of IOTLB
> :)

Yes, I should possibly do the same thing for context cache global
invalidations. IIUC context global invalidation should be a superset
of iotlb invalidation, so maybe I'll add one more patch to call iotlb
invalidation in context invalidation as well. Kevin/others, please
correct me if I misunderstood the spec. Thanks,

-- peterx