From: Mark McLoughlin Date: Thu, 5 Feb 2009 18:23:46 +0000 (+0000) Subject: KVM: Fix assigned devices circular locking dependency X-Git-Tag: v2.6.29-rc6~90^2~1 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=682edb4c01e690c7c7cd772dbd6f4e0fd74dc572;p=karo-tx-linux.git KVM: Fix assigned devices circular locking dependency kvm->slots_lock is outer to kvm->lock, so take slots_lock in kvm_vm_ioctl_assign_device() before taking kvm->lock, rather than taking it in kvm_iommu_map_memslots(). Cc: stable@kernel.org Signed-off-by: Mark McLoughlin Acked-by: Marcelo Tosatti Signed-off-by: Avi Kivity --- diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c index e9693a29d00e..4c4037503600 100644 --- a/virt/kvm/iommu.c +++ b/virt/kvm/iommu.c @@ -73,14 +73,13 @@ static int kvm_iommu_map_memslots(struct kvm *kvm) { int i, r = 0; - down_read(&kvm->slots_lock); for (i = 0; i < kvm->nmemslots; i++) { r = kvm_iommu_map_pages(kvm, kvm->memslots[i].base_gfn, kvm->memslots[i].npages); if (r) break; } - up_read(&kvm->slots_lock); + return r; } @@ -190,12 +189,11 @@ static void kvm_iommu_put_pages(struct kvm *kvm, static int kvm_iommu_unmap_memslots(struct kvm *kvm) { int i; - down_read(&kvm->slots_lock); + for (i = 0; i < kvm->nmemslots; i++) { kvm_iommu_put_pages(kvm, kvm->memslots[i].base_gfn, kvm->memslots[i].npages); } - up_read(&kvm->slots_lock); return 0; } diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index d9bbb20f230f..29a667ce35b0 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -466,6 +466,7 @@ static int kvm_vm_ioctl_assign_device(struct kvm *kvm, struct kvm_assigned_dev_kernel *match; struct pci_dev *dev; + down_read(&kvm->slots_lock); mutex_lock(&kvm->lock); match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head, @@ -527,6 +528,7 @@ static int kvm_vm_ioctl_assign_device(struct kvm *kvm, out: mutex_unlock(&kvm->lock); + up_read(&kvm->slots_lock); return r; out_list_del: list_del(&match->list); @@ -538,6 +540,7 @@ out_put: out_free: kfree(match); mutex_unlock(&kvm->lock); + up_read(&kvm->slots_lock); return r; } #endif