Mailing List Archive

[xen master] x86/mm: Refactor map_pages_to_xen to have only a single exit path
commit 08e6c6f80b018878476adc2c4e5679d2ce5cb4b1
Author: Wei Liu <wei.liu2@citrix.com>
AuthorDate: Sat Jan 11 21:57:41 2020 +0000
Commit: Jan Beulich <jbeulich@suse.com>
CommitDate: Tue Oct 20 14:19:31 2020 +0200

x86/mm: Refactor map_pages_to_xen to have only a single exit path

We will soon need to perform clean-ups before returning.

No functional change.

This is part of XSA-345.

Reported-by: Hongyan Xia <hongyxia@amazon.com>
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Hongyan Xia <hongyxia@amazon.com>
Signed-off-by: George Dunlap <george.dunlap@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
---
xen/arch/x86/mm.c | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 8c8f054186..0495b6891a 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -275,7 +275,7 @@ static l4_pgentry_t __read_mostly split_l4e;
* Originally cloned from share_xen_page_with_guest(), just to avoid setting
* PGC_xen_heap on non-heap (typically) MMIO pages. Other pieces got dropped
* simply because they're not needed in this context.
- */
+ */
static void __init assign_io_page(struct page_info *page)
{
set_gpfn_from_mfn(mfn_x(page_to_mfn(page)), INVALID_M2P_ENTRY);
@@ -5079,6 +5079,7 @@ int map_pages_to_xen(
l2_pgentry_t *pl2e, ol2e;
l1_pgentry_t *pl1e, ol1e;
unsigned int i;
+ int rc = -ENOMEM;

#define flush_flags(oldf) do { \
unsigned int o_ = (oldf); \
@@ -5099,7 +5100,8 @@ int map_pages_to_xen(
l3_pgentry_t ol3e, *pl3e = virt_to_xen_l3e(virt);

if ( !pl3e )
- return -ENOMEM;
+ goto out;
+
ol3e = *pl3e;

if ( cpu_has_page1gb &&
@@ -5189,7 +5191,7 @@ int map_pages_to_xen(

l2t = alloc_xen_pagetable();
if ( l2t == NULL )
- return -ENOMEM;
+ goto out;

for ( i = 0; i < L2_PAGETABLE_ENTRIES; i++ )
l2e_write(l2t + i,
@@ -5218,7 +5220,7 @@ int map_pages_to_xen(

pl2e = virt_to_xen_l2e(virt);
if ( !pl2e )
- return -ENOMEM;
+ goto out;

if ( ((((virt >> PAGE_SHIFT) | mfn_x(mfn)) &
((1u << PAGETABLE_ORDER) - 1)) == 0) &&
@@ -5262,7 +5264,7 @@ int map_pages_to_xen(
{
pl1e = virt_to_xen_l1e(virt);
if ( pl1e == NULL )
- return -ENOMEM;
+ goto out;
}
else if ( l2e_get_flags(*pl2e) & _PAGE_PSE )
{
@@ -5290,7 +5292,7 @@ int map_pages_to_xen(

l1t = alloc_xen_pagetable();
if ( l1t == NULL )
- return -ENOMEM;
+ goto out;

for ( i = 0; i < L1_PAGETABLE_ENTRIES; i++ )
l1e_write(&l1t[i],
@@ -5436,7 +5438,10 @@ int map_pages_to_xen(

#undef flush_flags

- return 0;
+ rc = 0;
+
+ out:
+ return rc;
}

int populate_pt_range(unsigned long virt, unsigned long nr_mfns)
--
generated by git-patchbot for /home/xen/git/xen.git#master