Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit f2e10669 authored by chai wen's avatar chai wen Committed by Gleb Natapov
Browse files

KVM: Drop FOLL_GET in GUP when doing async page fault 



Page pinning is not mandatory in kvm async page fault processing since
after async page fault event is delivered to a guest it accesses page once
again and does its own GUP.  Drop the FOLL_GET flag in GUP in async_pf
code, and do some simplifying in check/clear processing.

Suggested-by: default avatarGleb Natapov <gleb@redhat.com>
Signed-off-by: default avatarGu zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: default avatarchai wen <chaiw.fnst@cn.fujitsu.com>
Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
parent a7efdf6b

arch/x86/kvm/x86.c

+2 −2
Original line number Diff line number Diff line
@@ -7298,7 +7298,7 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work) 
	int r;



	if ((vcpu->arch.mmu.direct_map != work->arch.direct_map) ||

	      is_error_page(work->page))

	      work->wakeup_all)

		return;



	r = kvm_mmu_reload(vcpu);
@@ -7408,7 +7408,7 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu, 
	struct x86_exception fault;



	trace_kvm_async_pf_ready(work->arch.token, work->gva);

	if (is_error_page(work->page))

	if (work->wakeup_all)

		work->arch.token = ~0; /* broadcast wakeup */

	else

		kvm_del_async_pf_gfn(vcpu, work->arch.gfn);

include/linux/kvm_host.h

+1 −1
Original line number Diff line number Diff line
@@ -189,7 +189,7 @@ struct kvm_async_pf { 
	gva_t gva;

	unsigned long addr;

	struct kvm_arch_async_pf arch;

	struct page *page;

	bool   wakeup_all;

};



void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu);

include/trace/events/kvm.h

+4 −6
Original line number Diff line number Diff line
@@ -296,23 +296,21 @@ DEFINE_EVENT(kvm_async_pf_nopresent_ready, kvm_async_pf_ready, 


TRACE_EVENT(

	kvm_async_pf_completed,

	TP_PROTO(unsigned long address, struct page *page, u64 gva),

	TP_ARGS(address, page, gva),

	TP_PROTO(unsigned long address, u64 gva),

	TP_ARGS(address, gva),



	TP_STRUCT__entry(

		__field(unsigned long, address)

		__field(pfn_t, pfn)

		__field(u64, gva)

		),



	TP_fast_assign(

		__entry->address = address;

		__entry->pfn = page ? page_to_pfn(page) : 0;

		__entry->gva = gva;

		),



	TP_printk("gva %#llx address %#lx pfn %#llx",  __entry->gva,

		  __entry->address, __entry->pfn)

	TP_printk("gva %#llx address %#lx",  __entry->gva,

		  __entry->address)

);



#endif

virt/kvm/async_pf.c

+5 −12
Original line number Diff line number Diff line
@@ -56,7 +56,6 @@ void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu) 


static void async_pf_execute(struct work_struct *work)

{

	struct page *page = NULL;

	struct kvm_async_pf *apf =

		container_of(work, struct kvm_async_pf, work);

	struct mm_struct *mm = apf->mm;
@@ -68,13 +67,12 @@ static void async_pf_execute(struct work_struct *work) 


	use_mm(mm);

	down_read(&mm->mmap_sem);

	get_user_pages(current, mm, addr, 1, 1, 0, &page, NULL);

	get_user_pages(current, mm, addr, 1, 1, 0, NULL, NULL);

	up_read(&mm->mmap_sem);

	unuse_mm(mm);



	spin_lock(&vcpu->async_pf.lock);

	list_add_tail(&apf->link, &vcpu->async_pf.done);

	apf->page = page;

	spin_unlock(&vcpu->async_pf.lock);



	/*
@@ -82,7 +80,7 @@ static void async_pf_execute(struct work_struct *work) 
	 * this point

	 */



	trace_kvm_async_pf_completed(addr, page, gva);

	trace_kvm_async_pf_completed(addr, gva);



	if (waitqueue_active(&vcpu->wq))

		wake_up_interruptible(&vcpu->wq);
@@ -112,8 +110,6 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu) 
			list_entry(vcpu->async_pf.done.next,

				   typeof(*work), link);

		list_del(&work->link);

		if (!is_error_page(work->page))

			kvm_release_page_clean(work->page);

		kmem_cache_free(async_pf_cache, work);

	}

	spin_unlock(&vcpu->async_pf.lock);
@@ -133,14 +129,11 @@ void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu) 
		list_del(&work->link);

		spin_unlock(&vcpu->async_pf.lock);



		if (work->page)

		kvm_arch_async_page_ready(vcpu, work);

		kvm_arch_async_page_present(vcpu, work);



		list_del(&work->queue);

		vcpu->async_pf.queued--;

		if (!is_error_page(work->page))

			kvm_release_page_clean(work->page);

		kmem_cache_free(async_pf_cache, work);

	}

}
@@ -163,7 +156,7 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn, 
	if (!work)

		return 0;



	work->page = NULL;

	work->wakeup_all = false;

	work->vcpu = vcpu;

	work->gva = gva;

	work->addr = gfn_to_hva(vcpu->kvm, gfn);
@@ -203,7 +196,7 @@ int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu) 
	if (!work)

		return -ENOMEM;



	work->page = KVM_ERR_PTR_BAD_PAGE;

	work->wakeup_all = true;

	INIT_LIST_HEAD(&work->queue); /* for list_del to work */



	spin_lock(&vcpu->async_pf.lock);