Messages in this thread | | | Subject | Re: [PATCH v1 1/8] virtio: Force only split mode with protected guest | From | Jason Wang <> | Date | Thu, 3 Jun 2021 10:32:40 +0800 |
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在 2021/6/3 上午9:48, Andi Kleen 写道: > >> So we will see huge performance regression without indirect >> descriptor. We need to consider to address this. > > A regression would be when some existing case would be slower. > > That's not the case because the behavior for the existing cases does > not change. > > Anyways when there are performance problems they can be addressed, but > first is to make it secure.
I agree, but I want to know why indirect descriptor needs to be disabled. The table can't be wrote by the device since it's not coherent swiotlb mapping.
Thanks
> > -Andi > > >> >> Thanks >> >> >>> break; >>> case VIRTIO_RING_F_EVENT_IDX: >>> break; >>> @@ -2231,9 +2240,12 @@ void vring_transport_features(struct >>> virtio_device *vdev) >>> case VIRTIO_F_ACCESS_PLATFORM: >>> break; >>> case VIRTIO_F_RING_PACKED: >>> + if (protected_guest_has(VM_MEM_ENCRYPT)) >>> + goto clear; >>> break; >>> case VIRTIO_F_ORDER_PLATFORM: >>> break; >>> + clear: >>> default: >>> /* We don't understand this bit. */ >>> __virtio_clear_bit(vdev, i); >> >
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