diff mbox series

[v2,1/3] x86/mm: short-circuit HVM-only mode flags when !HVM

Message ID 5CD42E37020000780022D32F@prv1-mh.provo.novell.com (mailing list archive)
State New, archived
Headers show
Series x86/mm: guest_physmap_add_*() adjustments | expand

Commit Message

Jan Beulich May 9, 2019, 1:42 p.m. UTC 
#define-ing them to zero allows better code generation in this case,
and paves the way for more DCE, allowing to leave certain functions just
declared, but not defined.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
v2: New.

Comments

Wei Liu May 9, 2019, 5 p.m. UTC | #1 
On Thu, May 09, 2019 at 07:42:15AM -0600, Jan Beulich wrote:
> #define-ing them to zero allows better code generation in this case,
> and paves the way for more DCE, allowing to leave certain functions just
> declared, but not defined.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Reviewed-by: Wei Liu <wei.liu2@citrix.com>
George Dunlap May 13, 2019, 4:18 p.m. UTC | #2 
On 5/9/19 2:42 PM, Jan Beulich wrote:
> #define-ing them to zero allows better code generation in this case,
> and paves the way for more DCE, allowing to leave certain functions just
> declared, but not defined.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Reviewed-by: George Dunlap <george.dunlap@citrix.com>
diff mbox series

Patch

--- a/xen/arch/x86/mm/paging.c
+++ b/xen/arch/x86/mm/paging.c
@@ -837,7 +837,9 @@  int paging_enable(struct domain *d, u32
     switch ( mode & (PG_external | PG_translate | PG_refcounts) )
     {
     case 0:
+#if PG_external | PG_translate | PG_refcounts
     case PG_external | PG_translate | PG_refcounts:
+#endif
         break;
     default:
         return -EINVAL;
--- a/xen/include/asm-x86/paging.h
+++ b/xen/include/asm-x86/paging.h
@@ -46,19 +46,29 @@ 
 #define PG_SH_enable   0
 #define PG_SH_forced   0
 #endif
+#ifdef CONFIG_HVM
 #define PG_HAP_enable  (1U << PG_HAP_shift)
+#else
+#define PG_HAP_enable  0
+#endif
 
 /* common paging mode bits */
 #define PG_mode_shift  10 
+#ifdef CONFIG_HVM
 /* Refcounts based on shadow tables instead of guest tables */
 #define PG_refcounts   (XEN_DOMCTL_SHADOW_ENABLE_REFCOUNT << PG_mode_shift)
-/* Enable log dirty mode */
-#define PG_log_dirty   (XEN_DOMCTL_SHADOW_ENABLE_LOG_DIRTY << PG_mode_shift)
 /* Xen does p2m translation, not guest */
 #define PG_translate   (XEN_DOMCTL_SHADOW_ENABLE_TRANSLATE << PG_mode_shift)
 /* Xen does not steal address space from the domain for its own booking;
  * requires VT or similar mechanisms */
 #define PG_external    (XEN_DOMCTL_SHADOW_ENABLE_EXTERNAL << PG_mode_shift)
+#else
+#define PG_refcounts   0
+#define PG_translate   0
+#define PG_external    0
+#endif
+/* Enable log dirty mode */
+#define PG_log_dirty   (XEN_DOMCTL_SHADOW_ENABLE_LOG_DIRTY << PG_mode_shift)
 
 /* All paging modes. */
 #define PG_MASK (PG_refcounts | PG_log_dirty | PG_translate | PG_external)