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Koen Kooi
189ce92b4c
Signed-off-by: Koen Kooi <koen@dominion.thruhere.net> Signed-off-by: Denys Dmytriyenko <denys@ti.com>
84 lines
2.4 KiB
Diff
84 lines
2.4 KiB
Diff
From 2464830dde6595631a26a5178946f8d8d0ac974f Mon Sep 17 00:00:00 2001
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From: Alex Williamson <alex.williamson@redhat.com>
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Date: Tue, 17 Apr 2012 21:46:44 -0600
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Subject: [PATCH 003/117] KVM: lock slots_lock around device assignment
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(cherry picked from commit 21a1416a1c945c5aeaeaf791b63c64926018eb77)
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As pointed out by Jason Baron, when assigning a device to a guest
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we first set the iommu domain pointer, which enables mapping
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and unmapping of memory slots to the iommu. This leaves a window
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where this path is enabled, but we haven't synchronized the iommu
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mappings to the existing memory slots. Thus a slot being removed
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at that point could send us down unexpected code paths removing
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non-existent pinnings and iommu mappings. Take the slots_lock
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around creating the iommu domain and initial mappings as well as
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around iommu teardown to avoid this race.
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Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
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Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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---
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virt/kvm/iommu.c | 23 +++++++++++++++--------
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1 file changed, 15 insertions(+), 8 deletions(-)
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diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c
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index fd817a2..533db33 100644
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--- a/virt/kvm/iommu.c
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+++ b/virt/kvm/iommu.c
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@@ -239,9 +239,13 @@ int kvm_iommu_map_guest(struct kvm *kvm)
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return -ENODEV;
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}
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+ mutex_lock(&kvm->slots_lock);
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+
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kvm->arch.iommu_domain = iommu_domain_alloc(&pci_bus_type);
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- if (!kvm->arch.iommu_domain)
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- return -ENOMEM;
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+ if (!kvm->arch.iommu_domain) {
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+ r = -ENOMEM;
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+ goto out_unlock;
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+ }
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if (!allow_unsafe_assigned_interrupts &&
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!iommu_domain_has_cap(kvm->arch.iommu_domain,
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@@ -252,17 +256,16 @@ int kvm_iommu_map_guest(struct kvm *kvm)
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" module option.\n", __func__);
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iommu_domain_free(kvm->arch.iommu_domain);
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kvm->arch.iommu_domain = NULL;
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- return -EPERM;
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+ r = -EPERM;
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+ goto out_unlock;
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}
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r = kvm_iommu_map_memslots(kvm);
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if (r)
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- goto out_unmap;
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-
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- return 0;
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+ kvm_iommu_unmap_memslots(kvm);
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-out_unmap:
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- kvm_iommu_unmap_memslots(kvm);
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+out_unlock:
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+ mutex_unlock(&kvm->slots_lock);
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return r;
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}
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@@ -338,7 +341,11 @@ int kvm_iommu_unmap_guest(struct kvm *kvm)
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if (!domain)
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return 0;
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+ mutex_lock(&kvm->slots_lock);
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kvm_iommu_unmap_memslots(kvm);
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+ kvm->arch.iommu_domain = NULL;
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+ mutex_unlock(&kvm->slots_lock);
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+
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iommu_domain_free(domain);
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return 0;
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}
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--
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1.7.9.5
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