KVM: Enable Function Level Reset for assigned device (6eb55818) · Commits · 戴 / test

Ideally, every assigned device should in a clear condition before and after assignment, so that the former state of device won't affect later work. Some devices provide a mechanism named Function Level Reset, which is defined in PCI/PCI-e document. We should execute it before and after device assignment. (But sadly, the feature is new, and most device on the market now don't support it. We are considering using D0/D3hot transmit to emulate it later, but not that elegant and reliable as FLR itself.) [Update: Reminded by Xiantao, execute FLR after we ensure that the device can be assigned to the guest.] Signed-off-by:

Sheng Yang <sheng@linux.intel.com> Signed-off-by:

Avi Kivity <avi@redhat.com>

arch/x86/kvm/x86.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -4148,8 +4148,8 @@ static void kvm_free_vcpus(struct kvm *kvm)

		void kvm_arch_destroy_vm(struct kvm *kvm)
		{
		kvm_iommu_unmap_guest(kvm);
		kvm_free_all_assigned_devices(kvm);
		kvm_iommu_unmap_guest(kvm);
		kvm_free_pit(kvm);
		kfree(kvm->arch.vpic);
		kfree(kvm->arch.vioapic);

virt/kvm/kvm_main.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -152,6 +152,8 @@ static void kvm_free_assigned_device(struct kvm *kvm,
		*/
		kvm_put_kvm(kvm);

		pci_reset_function(assigned_dev->dev);

		pci_release_regions(assigned_dev->dev);
		pci_disable_device(assigned_dev->dev);
		pci_dev_put(assigned_dev->dev);
		@@ -283,6 +285,9 @@ static int kvm_vm_ioctl_assign_device(struct kvm *kvm,
		__func__);
		goto out_disable;
		}

		pci_reset_function(dev);

		match->assigned_dev_id = assigned_dev->assigned_dev_id;
		match->host_busnr = assigned_dev->busnr;
		match->host_devfn = assigned_dev->devfn;

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