diff mbox series

[v2,(resend),01/27] xen/vmap: Check the page has been mapped in vm_init_type()

Message ID 20240116192611.41112-2-eliasely@amazon.com (mailing list archive)
State New
Headers show
Series Remove the directmap | expand

Commit Message

Elias El Yandouzi Jan. 16, 2024, 7:25 p.m. UTC 
From: Julien Grall <jgrall@amazon.com>

The function map_pages_to_xen() could fail if it can't allocate the
underlying page tables or (at least on Arm) if the area was already
mapped.

The first error is caught by clear_page() because it would fault.
However, the second error while very unlikely is not caught at all.

As this is boot code, use BUG_ON() to check if map_pages_to_xen() has
succeeded.

Signed-off-by: Julien Grall <jgrall@amazon.com>
Signed-off-by: Elias El Yandouzi <eliasely@amazon.com>

----

    Changes in v2:
        - New patch

Comments

Jan Beulich Jan. 25, 2024, 4:14 p.m. UTC | #1 
On 16.01.2024 20:25, Elias El Yandouzi wrote:
> From: Julien Grall <jgrall@amazon.com>
> 
> The function map_pages_to_xen() could fail if it can't allocate the
> underlying page tables or (at least on Arm) if the area was already
> mapped.
> 
> The first error is caught by clear_page() because it would fault.
> However, the second error while very unlikely is not caught at all.
> 
> As this is boot code, use BUG_ON() to check if map_pages_to_xen() has
> succeeded.
> 
> Signed-off-by: Julien Grall <jgrall@amazon.com>
> Signed-off-by: Elias El Yandouzi <eliasely@amazon.com>

Acked-by: Jan Beulich <jbeulich@suse.com>
diff mbox series

Patch

diff --git a/xen/common/vmap.c b/xen/common/vmap.c
index 330e2ba897..830f64c5ef 100644
--- a/xen/common/vmap.c
+++ b/xen/common/vmap.c
@@ -35,8 +35,11 @@  void __init vm_init_type(enum vmap_region type, void *start, void *end)
     for ( i = 0, va = (unsigned long)vm_bitmap(type); i < nr; ++i, va += PAGE_SIZE )
     {
         struct page_info *pg = alloc_domheap_page(NULL, 0);
+        int rc;
+
+        rc = map_pages_to_xen(va, page_to_mfn(pg), 1, PAGE_HYPERVISOR);
+        BUG_ON(rc);
 
-        map_pages_to_xen(va, page_to_mfn(pg), 1, PAGE_HYPERVISOR);
         clear_page((void *)va);
     }
     bitmap_fill(vm_bitmap(type), vm_low[type]);