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-rw-r--r--arch/x86/xen/setup.c16
1 files changed, 11 insertions, 5 deletions
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 403f5cc5415b..6243651623d5 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -218,13 +218,19 @@ static void __init xen_set_identity_and_release_chunk(
unsigned long pfn;
/*
- * If the PFNs are currently mapped, the VA mapping also needs
- * to be updated to be 1:1.
+ * If the PFNs are currently mapped, clear the mappings
+ * (except for the ISA region which must be 1:1 mapped) to
+ * release the refcounts (in Xen) on the original frames.
*/
- for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++)
+ for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++) {
+ pte_t pte = __pte_ma(0);
+
+ if (pfn < PFN_UP(ISA_END_ADDRESS))
+ pte = mfn_pte(pfn, PAGE_KERNEL_IO);
+
(void)HYPERVISOR_update_va_mapping(
- (unsigned long)__va(pfn << PAGE_SHIFT),
- mfn_pte(pfn, PAGE_KERNEL_IO), 0);
+ (unsigned long)__va(pfn << PAGE_SHIFT), pte, 0);
+ }
if (start_pfn < nr_pages)
*released += xen_release_chunk(