58 lines
2.2 KiB
Diff
58 lines
2.2 KiB
Diff
From add80ba59a85aca4c5e2619dee95557d2ec14169 Mon Sep 17 00:00:00 2001
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From: eperezma <eperezma@redhat.com>
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Date: Mon, 11 Jan 2021 14:36:14 -0500
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Subject: intel_iommu: Skip page walking on device iotlb invalidations
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: eperezma <eperezma@redhat.com>
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Message-id: <20210111143615.303645-5-eperezma@redhat.com>
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Patchwork-id: 100572
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O-Subject: [RHEL-AV-8.4.0 qemu-kvm PATCH 4/5] intel_iommu: Skip page walking on device iotlb invalidations
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Bugzilla: 1845758
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RH-Acked-by: Xiao Wang <jasowang@redhat.com>
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RH-Acked-by: David Hildenbrand <david@redhat.com>
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RH-Acked-by: Peter Xu <peterx@redhat.com>
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Although they didn't reach the notifier because of the filtering in
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memory_region_notify_iommu_one, the vt-d was still splitting huge
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memory invalidations in chunks. Skipping it.
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This improves performance in case of netperf with vhost-net:
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* TCP_STREAM: From 1923.6Mbit/s to 2175.13Mbit/s (13%)
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* TCP_RR: From 8464.73 trans/s to 8932.703333 trans/s (5.5%)
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* UDP_RR: From 8562.08 trans/s to 9005.62/s (5.1%)
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* UDP_STREAM: No change observed (insignificant 0.1% improvement)
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Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
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Acked-by: Jason Wang <jasowang@redhat.com>
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Message-Id: <20201116165506.31315-5-eperezma@redhat.com>
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Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
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Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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(cherry picked from commit f7701e2c7983b680790af47117577b285b6a1aed)
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Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
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Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
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---
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hw/i386/intel_iommu.c | 4 ++++
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1 file changed, 4 insertions(+)
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diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
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index edc3090f91..0cc71e4057 100644
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--- a/hw/i386/intel_iommu.c
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+++ b/hw/i386/intel_iommu.c
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@@ -1478,6 +1478,10 @@ static int vtd_sync_shadow_page_table(VTDAddressSpace *vtd_as)
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VTDContextEntry ce;
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IOMMUNotifier *n;
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+ if (!(vtd_as->iommu.iommu_notify_flags & IOMMU_NOTIFIER_IOTLB_EVENTS)) {
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+ return 0;
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+ }
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+
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ret = vtd_dev_to_context_entry(vtd_as->iommu_state,
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pci_bus_num(vtd_as->bus),
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vtd_as->devfn, &ce);
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--
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2.18.4
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