On 10/10/2016 20:01, Neo Jia wrote:
>> Hi Neo,
>>
>> AFAIK this is needed because KVMGT doesn't paravirtualize the PPGTT,
>> while nVidia does.
>
> Hi Paolo and Xiaoguang,
>
> I am just wondering how device driver can register a notifier so he can be
> notified for write-protected pages when writes are happening.
It can't yet, but the API is ready for that. kvm_vfio_set_group is
currently where a struct kvm_device* and struct vfio_group* touch. Given
a struct kvm_device*, dev->kvm provides the struct kvm to be passed to
kvm_page_track_register_notifier. So I guess you could add a callback
that passes the struct kvm_device* to the mdev device.
Xiaoguang and Guangrong, what were your plans? We discussed it briefly
at KVM Forum but I don't remember the details.
Paolo
> Thanks,
> Neo
>
>>
>> Paolo
>>
>>> Thanks,
>>> Neo
>>>
>>>>
>>>> Reviewed-by: Xiao Guangrong <guangrong.xiao@xxxxxxxxx>
>>>> Signed-off-by: Chen Xiaoguang <xiaoguang.chen@xxxxxxxxx>
>>>> ---
>>>> arch/x86/include/asm/kvm_page_track.h | 9 +++++++++
>>>> arch/x86/kvm/page_track.c | 25 +++++++++++++++++++++++++
>>>> arch/x86/kvm/x86.c | 2 +-
>>>> 3 files changed, 35 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/arch/x86/include/asm/kvm_page_track.h b/arch/x86/include/asm/kvm_page_track.h
>>>> index c2b8d24..5f66597 100644
>>>> --- a/arch/x86/include/asm/kvm_page_track.h
>>>> +++ b/arch/x86/include/asm/kvm_page_track.h
>>>> @@ -32,6 +32,14 @@ struct kvm_page_track_notifier_node {
>>>> */
>>>> void (*track_write)(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
>>>> int bytes);
>>>> + /*
>>>> + * It is called when memory slot is being moved or removed
>>>> + * users can drop write-protection for the pages in that memory slot
>>>> + *
>>>> + * @kvm: the kvm where memory slot being moved or removed
>>>> + * @slot: the memory slot being moved or removed
>>>> + */
>>>> + void (*track_flush_slot)(struct kvm *kvm, struct kvm_memory_slot *slot);
>>>> };
>>>>
>>>> void kvm_page_track_init(struct kvm *kvm);
>>>> @@ -58,4 +66,5 @@ kvm_page_track_unregister_notifier(struct kvm *kvm,
>>>> struct kvm_page_track_notifier_node *n);
>>>> void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
>>>> int bytes);
>>>> +void kvm_page_track_flush_slot(struct kvm *kvm, struct kvm_memory_slot *slot);
>>>> #endif
>>>> diff --git a/arch/x86/kvm/page_track.c b/arch/x86/kvm/page_track.c
>>>> index b431539..e79bb25 100644
>>>> --- a/arch/x86/kvm/page_track.c
>>>> +++ b/arch/x86/kvm/page_track.c
>>>> @@ -225,3 +225,28 @@ void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
>>>> n->track_write(vcpu, gpa, new, bytes);
>>>> srcu_read_unlock(&head->track_srcu, idx);
>>>> }
>>>> +
>>>> +/*
>>>> + * Notify the node that memory slot is being removed or moved so that it can
>>>> + * drop write-protection for the pages in the memory slot.
>>>> + *
>>>> + * The node should figure out it has any write-protected pages in this slot
>>>> + * by itself.
>>>> + */
>>>> +void kvm_page_track_flush_slot(struct kvm *kvm, struct kvm_memory_slot *slot)
>>>> +{
>>>> + struct kvm_page_track_notifier_head *head;
>>>> + struct kvm_page_track_notifier_node *n;
>>>> + int idx;
>>>> +
>>>> + head = &kvm->arch.track_notifier_head;
>>>> +
>>>> + if (hlist_empty(&head->track_notifier_list))
>>>> + return;
>>>> +
>>>> + idx = srcu_read_lock(&head->track_srcu);
>>>> + hlist_for_each_entry_rcu(n, &head->track_notifier_list, node)
>>>> + if (n->track_flush_slot)
>>>> + n->track_flush_slot(kvm, slot);
>>>> + srcu_read_unlock(&head->track_srcu, idx);
>>>> +}
>>>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>>>> index 87f5dbb..f8ae90c 100644
>>>> --- a/arch/x86/kvm/x86.c
>>>> +++ b/arch/x86/kvm/x86.c
>>>> @@ -8278,7 +8278,7 @@ void kvm_arch_flush_shadow_all(struct kvm *kvm)
>>>> void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
>>>> struct kvm_memory_slot *slot)
>>>> {
>>>> - kvm_mmu_invalidate_zap_all_pages(kvm);
>>>> + kvm_page_track_flush_slot(kvm, slot);
>>>> }
>>>>
>>>> static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu)
>>>> --
>>>> 1.9.1
>>>>
>>>> --
>>>> To unsubscribe from this list: send the line "unsubscribe kvm" in
>>>> the body of a message to majordomo@xxxxxxxxxxxxxxx
>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>> --
>> To unsubscribe from this list: send the line "unsubscribe kvm" in
>> the body of a message to majordomo@xxxxxxxxxxxxxxx
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
