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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