kvm: fix kvm_is_mmio_pfn() and rename to kvm_is_reserved_pfn()
This reverts commit 85c8555ff0 ("KVM: check for !is_zero_pfn() in
kvm_is_mmio_pfn()") and renames the function to kvm_is_reserved_pfn.
The problem being addressed by the patch above was that some ARM code
based the memory mapping attributes of a pfn on the return value of
kvm_is_mmio_pfn(), whose name indeed suggests that such pfns should
be mapped as device memory.
However, kvm_is_mmio_pfn() doesn't do quite what it says on the tin,
and the existing non-ARM users were already using it in a way which
suggests that its name should probably have been 'kvm_is_reserved_pfn'
from the beginning, e.g., whether or not to call get_page/put_page on
it etc. This means that returning false for the zero page is a mistake
and the patch above should be reverted.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 25ffac9..3cee7b1 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -107,10 +107,10 @@
static bool largepages_enabled = true;
-bool kvm_is_mmio_pfn(pfn_t pfn)
+bool kvm_is_reserved_pfn(pfn_t pfn)
{
if (pfn_valid(pfn))
- return !is_zero_pfn(pfn) && PageReserved(pfn_to_page(pfn));
+ return PageReserved(pfn_to_page(pfn));
return true;
}
@@ -1321,7 +1321,7 @@
else if ((vma->vm_flags & VM_PFNMAP)) {
pfn = ((addr - vma->vm_start) >> PAGE_SHIFT) +
vma->vm_pgoff;
- BUG_ON(!kvm_is_mmio_pfn(pfn));
+ BUG_ON(!kvm_is_reserved_pfn(pfn));
} else {
if (async && vma_is_valid(vma, write_fault))
*async = true;
@@ -1427,7 +1427,7 @@
if (is_error_noslot_pfn(pfn))
return KVM_ERR_PTR_BAD_PAGE;
- if (kvm_is_mmio_pfn(pfn)) {
+ if (kvm_is_reserved_pfn(pfn)) {
WARN_ON(1);
return KVM_ERR_PTR_BAD_PAGE;
}
@@ -1456,7 +1456,7 @@
void kvm_release_pfn_clean(pfn_t pfn)
{
- if (!is_error_noslot_pfn(pfn) && !kvm_is_mmio_pfn(pfn))
+ if (!is_error_noslot_pfn(pfn) && !kvm_is_reserved_pfn(pfn))
put_page(pfn_to_page(pfn));
}
EXPORT_SYMBOL_GPL(kvm_release_pfn_clean);
@@ -1477,7 +1477,7 @@
void kvm_set_pfn_dirty(pfn_t pfn)
{
- if (!kvm_is_mmio_pfn(pfn)) {
+ if (!kvm_is_reserved_pfn(pfn)) {
struct page *page = pfn_to_page(pfn);
if (!PageReserved(page))
SetPageDirty(page);
@@ -1487,14 +1487,14 @@
void kvm_set_pfn_accessed(pfn_t pfn)
{
- if (!kvm_is_mmio_pfn(pfn))
+ if (!kvm_is_reserved_pfn(pfn))
mark_page_accessed(pfn_to_page(pfn));
}
EXPORT_SYMBOL_GPL(kvm_set_pfn_accessed);
void kvm_get_pfn(pfn_t pfn)
{
- if (!kvm_is_mmio_pfn(pfn))
+ if (!kvm_is_reserved_pfn(pfn))
get_page(pfn_to_page(pfn));
}
EXPORT_SYMBOL_GPL(kvm_get_pfn);