This patch allows VMA's that contain no backing page to be used for guest
memory. This is a drop-in replacement for Ben-Ami's first page in his direct
mmio series. Here, we continue to allow mmio pages to be represented in the
rmap.
Signed-off-by: Anthony Liguori <[EMAIL PROTECTED]>
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f095b73..11b26f5 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -531,6 +531,7 @@ pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn)
struct page *page[1];
unsigned long addr;
int npages;
+ pfn_t pfn;
might_sleep();
@@ -543,19 +544,36 @@ pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn)
npages = get_user_pages(current, current->mm, addr, 1, 1, 1, page,
NULL);
- if (npages != 1) {
- get_page(bad_page);
- return page_to_pfn(bad_page);
- }
+ if (unlikely(npages != 1)) {
+ struct vm_area_struct *vma;
+
+ vma = find_vma(current->mm, addr);
+ if (vma == NULL) {
+ get_page(bad_page);
+ return page_to_pfn(bad_page);
+ }
+
+ BUG_ON(!(vma->vm_flags & VM_IO));
- return page_to_pfn(page[0]);
+ pfn = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
+ BUG_ON(pfn_valid(pfn));
+ } else
+ pfn = page_to_pfn(page[0]);
+
+ return pfn;
}
EXPORT_SYMBOL_GPL(gfn_to_pfn);
struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn)
{
- return pfn_to_page(gfn_to_pfn(kvm, gfn));
+ pfn_t pfn;
+
+ pfn = gfn_to_pfn(kvm, gfn);
+ if (pfn_valid(pfn))
+ return pfn_to_page(pfn);
+
+ return NULL;
}
EXPORT_SYMBOL_GPL(gfn_to_page);
@@ -568,7 +586,8 @@ EXPORT_SYMBOL_GPL(kvm_release_page_clean);
void kvm_release_pfn_clean(pfn_t pfn)
{
- put_page(pfn_to_page(pfn));
+ if (pfn_valid(pfn))
+ put_page(pfn_to_page(pfn));
}
EXPORT_SYMBOL_GPL(kvm_release_pfn_clean);
@@ -593,21 +612,25 @@ EXPORT_SYMBOL_GPL(kvm_set_page_dirty);
void kvm_set_pfn_dirty(pfn_t pfn)
{
- struct page *page = pfn_to_page(pfn);
- if (!PageReserved(page))
- SetPageDirty(page);
+ if (pfn_valid(pfn)) {
+ struct page *page = pfn_to_page(pfn);
+ if (!PageReserved(page))
+ SetPageDirty(page);
+ }
}
EXPORT_SYMBOL_GPL(kvm_set_pfn_dirty);
void kvm_set_pfn_accessed(pfn_t pfn)
{
- mark_page_accessed(pfn_to_page(pfn));
+ if (pfn_valid(pfn))
+ mark_page_accessed(pfn_to_page(pfn));
}
EXPORT_SYMBOL_GPL(kvm_set_pfn_accessed);
void kvm_get_pfn(pfn_t pfn)
{
- get_page(pfn_to_page(pfn));
+ if (pfn_valid(pfn))
+ get_page(pfn_to_page(pfn));
}
EXPORT_SYMBOL_GPL(kvm_get_pfn);
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