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authorAnthony Liguori <aliguori@us.ibm.com>2008-04-30 15:37:07 -0500
committerAvi Kivity <avi@qumranet.com>2008-07-20 12:40:49 +0300
commit2e2e3738af33575cba59597acd5e80cdd5ec11ee (patch)
tree8ba77f83b781bf219a28986b31802b48858cd869 /virt/kvm
parentd2ebb4103ff349af6dac14955bf93e57487a6694 (diff)
downloadlinux-linaro-2e2e3738af33575cba59597acd5e80cdd5ec11ee.tar.gz
KVM: Handle vma regions with no backing page
This patch allows VMAs that contain no backing page to be used for guest memory. This is useful for assigning mmio regions to a guest. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'virt/kvm')
-rw-r--r--virt/kvm/kvm_main.c49
1 files changed, 37 insertions, 12 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index b6a59498b5a..f9dd20606c4 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -532,6 +532,7 @@ 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();
@@ -544,19 +545,38 @@ 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;
- return page_to_pfn(page[0]);
+ vma = find_vma(current->mm, addr);
+ if (vma == NULL || addr < vma->vm_start ||
+ !(vma->vm_flags & VM_PFNMAP)) {
+ get_page(bad_page);
+ return page_to_pfn(bad_page);
+ }
+
+ 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);
+
+ WARN_ON(!pfn_valid(pfn));
+
+ get_page(bad_page);
+ return bad_page;
}
EXPORT_SYMBOL_GPL(gfn_to_page);
@@ -569,7 +589,8 @@ 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);
@@ -594,21 +615,25 @@ 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);