Messages in this thread |  | | Subject | Re: [PATCH RFC 04/15] KVM: Implement ring-based dirty memory tracking | From | Jason Wang <> | Date | Wed, 4 Dec 2019 18:38:35 +0800 |
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On 2019/11/30 上午5:34, Peter Xu wrote: > +int kvm_dirty_ring_push(struct kvm_dirty_ring *ring, > + struct kvm_dirty_ring_indexes *indexes, > + u32 slot, u64 offset, bool lock) > +{ > + int ret; > + struct kvm_dirty_gfn *entry; > + > + if (lock) > + spin_lock(&ring->lock); > + > + if (kvm_dirty_ring_full(ring)) { > + ret = -EBUSY; > + goto out; > + } > + > + entry = &ring->dirty_gfns[ring->dirty_index & (ring->size - 1)]; > + entry->slot = slot; > + entry->offset = offset;
Haven't gone through the whole series, sorry if it was a silly question but I wonder things like this will suffer from similar issue on virtually tagged archs as mentioned in [1].
Is this better to allocate the ring from userspace and set to KVM instead? Then we can use copy_to/from_user() friends (a little bit slow on recent CPUs).
[1] https://lkml.org/lkml/2019/4/9/5
Thanks
> + smp_wmb(); > + ring->dirty_index++; > + WRITE_ONCE(indexes->avail_index, ring->dirty_index); > + ret = kvm_dirty_ring_used(ring) >= ring->soft_limit; > + pr_info("%s: slot %u offset %llu used %u\n", > + __func__, slot, offset, kvm_dirty_ring_used(ring)); > + > +out:
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