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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: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Gleb Natapov 2010-10-19 18:13:41 +02:00 committed by Avi Kivity
parent fc5f06fac6
commit 8030089f9e
1 changed files with 17 additions and 13 deletions
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30
virt/kvm/kvm_main.c
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@ -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]);