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-rw-r--r--arch/x86/include/asm/xen/page.h12
-rw-r--r--arch/x86/xen/p2m.c10
-rw-r--r--arch/x86/xen/setup.c25
3 files changed, 21 insertions, 26 deletions
diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index 1a162e559753..7068e4bb057d 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -87,6 +87,18 @@ clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
#endif
/*
+ * The maximum amount of extra memory compared to the base size. The
+ * main scaling factor is the size of struct page. At extreme ratios
+ * of base:extra, all the base memory can be filled with page
+ * structures for the extra memory, leaving no space for anything
+ * else.
+ *
+ * 10x seems like a reasonable balance between scaling flexibility and
+ * leaving a practically usable system.
+ */
+#define XEN_EXTRA_MEM_RATIO (10)
+
+/*
* Helper functions to write or read unsigned long values to/from
* memory, when the access may fault.
*/
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 9545b8df5315..a3cc33091f46 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -416,6 +416,9 @@ void __init xen_vmalloc_p2m_tree(void)
xen_p2m_last_pfn = xen_max_p2m_pfn;
p2m_limit = (phys_addr_t)P2M_LIMIT * 1024 * 1024 * 1024 / PAGE_SIZE;
+ if (!p2m_limit && IS_ENABLED(CONFIG_XEN_UNPOPULATED_ALLOC))
+ p2m_limit = xen_start_info->nr_pages * XEN_EXTRA_MEM_RATIO;
+
vm.flags = VM_ALLOC;
vm.size = ALIGN(sizeof(unsigned long) * max(xen_max_p2m_pfn, p2m_limit),
PMD_SIZE * PMDS_PER_MID_PAGE);
@@ -652,10 +655,9 @@ bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
pte_t *ptep;
unsigned int level;
- if (unlikely(pfn >= xen_p2m_size)) {
- BUG_ON(mfn != INVALID_P2M_ENTRY);
- return true;
- }
+ /* Only invalid entries allowed above the highest p2m covered frame. */
+ if (unlikely(pfn >= xen_p2m_size))
+ return mfn == INVALID_P2M_ENTRY;
/*
* The interface requires atomic updates on p2m elements.
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 7eab14d56369..1a3b75652fa4 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -59,18 +59,6 @@ static struct {
} xen_remap_buf __initdata __aligned(PAGE_SIZE);
static unsigned long xen_remap_mfn __initdata = INVALID_P2M_ENTRY;
-/*
- * The maximum amount of extra memory compared to the base size. The
- * main scaling factor is the size of struct page. At extreme ratios
- * of base:extra, all the base memory can be filled with page
- * structures for the extra memory, leaving no space for anything
- * else.
- *
- * 10x seems like a reasonable balance between scaling flexibility and
- * leaving a practically usable system.
- */
-#define EXTRA_MEM_RATIO (10)
-
static bool xen_512gb_limit __initdata = IS_ENABLED(CONFIG_XEN_512GB);
static void __init xen_parse_512gb(void)
@@ -790,20 +778,13 @@ char * __init xen_memory_setup(void)
extra_pages += max_pages - max_pfn;
/*
- * Clamp the amount of extra memory to a EXTRA_MEM_RATIO
- * factor the base size. On non-highmem systems, the base
- * size is the full initial memory allocation; on highmem it
- * is limited to the max size of lowmem, so that it doesn't
- * get completely filled.
+ * Clamp the amount of extra memory to a XEN_EXTRA_MEM_RATIO
+ * factor the base size.
*
* Make sure we have no memory above max_pages, as this area
* isn't handled by the p2m management.
- *
- * In principle there could be a problem in lowmem systems if
- * the initial memory is also very large with respect to
- * lowmem, but we won't try to deal with that here.
*/
- extra_pages = min3(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
+ extra_pages = min3(XEN_EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
extra_pages, max_pages - max_pfn);
i = 0;
addr = xen_e820_table.entries[0].addr;