From: Eugenio Pérez <epere...@redhat.com> Although they didn't reach the notifier because of the filtering in memory_region_notify_iommu_one, the vt-d was still splitting huge memory invalidations in chunks. Skipping it.
This improves performance in case of netperf with vhost-net: * TCP_STREAM: From 1923.6Mbit/s to 2175.13Mbit/s (13%) * TCP_RR: From 8464.73 trans/s to 8932.703333 trans/s (5.5%) * UDP_RR: From 8562.08 trans/s to 9005.62/s (5.1%) * UDP_STREAM: No change observed (insignificant 0.1% improvement) Signed-off-by: Eugenio Pérez <epere...@redhat.com> Acked-by: Jason Wang <jasow...@redhat.com> Message-Id: <20201116165506.31315-5-epere...@redhat.com> Reviewed-by: Michael S. Tsirkin <m...@redhat.com> Signed-off-by: Michael S. Tsirkin <m...@redhat.com> --- hw/i386/intel_iommu.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c index edc3090f91..0cc71e4057 100644 --- a/hw/i386/intel_iommu.c +++ b/hw/i386/intel_iommu.c @@ -1478,6 +1478,10 @@ static int vtd_sync_shadow_page_table(VTDAddressSpace *vtd_as) VTDContextEntry ce; IOMMUNotifier *n; + if (!(vtd_as->iommu.iommu_notify_flags & IOMMU_NOTIFIER_IOTLB_EVENTS)) { + return 0; + } + ret = vtd_dev_to_context_entry(vtd_as->iommu_state, pci_bus_num(vtd_as->bus), vtd_as->devfn, &ce); -- MST