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Commit 8030089f authored by Gleb Natapov's avatar Gleb Natapov Committed by Avi Kivity
Browse files

KVM: improve hva_to_pfn() readability 



Improve vma handling code readability in hva_to_pfn() and fix
async pf handling code to properly check vma returned by find_vma().

Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent fc5f06fa

virt/kvm/kvm_main.c

+17 −13
Original line number Diff line number Diff line
@@ -952,6 +952,12 @@ unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn) 
}

EXPORT_SYMBOL_GPL(gfn_to_hva);



static pfn_t get_fault_pfn(void)

{

	get_page(fault_page);

	return fault_pfn;

}



static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr, bool atomic,

			bool *async)

{
@@ -974,7 +980,7 @@ static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr, bool atomic, 
		struct vm_area_struct *vma;



		if (atomic)

			goto return_fault_page;

			return get_fault_pfn();



		down_read(&current->mm->mmap_sem);

		if (is_hwpoison_address(addr)) {
@@ -983,22 +989,20 @@ static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr, bool atomic, 
			return page_to_pfn(hwpoison_page);

		}



		vma = find_vma(current->mm, addr);

		vma = find_vma_intersection(current->mm, addr, addr+1);



		if (vma == NULL || addr < vma->vm_start ||

		    !(vma->vm_flags & VM_PFNMAP)) {

			if (async && !(vma->vm_flags & VM_PFNMAP) &&

			    (vma->vm_flags & VM_WRITE))

		if (vma == NULL)

			pfn = get_fault_pfn();

		else if ((vma->vm_flags & VM_PFNMAP)) {

			pfn = ((addr - vma->vm_start) >> PAGE_SHIFT) +

				vma->vm_pgoff;

			BUG_ON(!kvm_is_mmio_pfn(pfn));

		} else {

			if (async && (vma->vm_flags & VM_WRITE))

				*async = true;

			up_read(&current->mm->mmap_sem);

return_fault_page:

			get_page(fault_page);

			return page_to_pfn(fault_page);

			pfn = get_fault_pfn();

		}



		pfn = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;

		up_read(&current->mm->mmap_sem);

		BUG_ON(!kvm_is_mmio_pfn(pfn));

	} else

		pfn = page_to_pfn(page[0]);