x86/xen: Fix xen_e820_swap_entry_with_ram()

When swapping a not page-aligned E820 map entry with RAM, the start
address of the modified entry is calculated wrong (the offset into the
page is subtracted instead of being added to the page address).

Fixes: be35d91c8880 ("xen: tolerate ACPI NVS memory overlapping with Xen allocated memory")
Reported-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Message-ID: <20260505102417.208138-1-jgross@suse.com>

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index bb95a05259b895d719322612db296019316c01e6..41251d4cf953f2a08de3c8906057cf579e19b77e 100644 (file)
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -655,7 +655,7 @@ static void __init xen_e820_swap_entry_with_ram(struct e820_entry *swap_entry)
                        /* Fill new entry (keep size and page offset). */
                        entry->type = swap_entry->type;
                        entry->addr = entry_end - swap_size +
-                                     swap_addr - swap_entry->addr;
+                                     swap_entry->addr - swap_addr;
                        entry->size = swap_entry->size;
 
                        /* Convert old entry to RAM, align to pages. */