On 09/10/2016 10:31, Neo Jia wrote:
> On Sun, Oct 09, 2016 at 03:41:43PM +0800, Xiaoguang Chen wrote:
>> When a memory slot is being moved or removed users of page track
>> can be notified. So users can drop write-protection for the pages
>> in that memory slot.
>>
>> This notifier type is needed by KVMGT to sync up its shadow page
>> table when memory slot is being moved or removed.
>
> Hi Xiaoguang,
>
> How is this supposed to be used by the kvmgt?
Hi Neo,
AFAIK this is needed because KVMGT doesn't paravirtualize the PPGTT,
while nVidia does.
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
>>
>> --
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