Re: [Xen-ia64-devel] [PATCH] fix memory leak when domVTI is created

[Tristan Gingold <Tristan.Gingold@xxxxxxxx>]

Le Vendredi 28 Juillet 2006 12:30, Isaku Yamahata a écrit :
> Please discard the previous one. Use the attached one.
> Sorry for confusion.
>
> On Fri, Jul 28, 2006 at 12:50:08PM +0900, Isaku Yamahata wrote:
> > fix memory leak when VT-i domain is created.
> > When domain is created, xend sets max vcpu before domain setup.
> > So alloc_vcpu_struct() thinks that the domain is normal domU, not domVTI.
> > And next xend set the domain as domVTI. so the memory is allocated for
> > domU won't be freed.
> >
> > --
> > yamahata
Good catch, but I have a few comments.

diff -r 2d73714911c2 -r a8eddc3f1f82 xen/arch/ia64/xen/domain.c
--- a/xen/arch/ia64/xen/domain.c        Thu Jul 27 10:43:34 2006 -0600
+++ b/xen/arch/ia64/xen/domain.c        Fri Jul 28 19:28:44 2006 +0900
@@ -261,13 +261,19 @@ struct vcpu *alloc_vcpu_struct(struct do
 
        if (!is_idle_domain(d)) {
            if (!d->arch.is_vti) {
-               /* Create privregs page only if not VTi.  */
-               v->arch.privregs = 
-                   alloc_xenheap_pages(get_order(sizeof(mapped_regs_t)));
-               BUG_ON(v->arch.privregs == NULL);
-               memset(v->arch.privregs, 0, PAGE_SIZE);
-               share_xen_page_with_guest(virt_to_page(v->arch.privregs),
-                                         d, XENSHARE_writable);
+            int order;
+            int i;
+
+            /* Create privregs page only if not VTi.  */
+            order = get_order_from_shift(XMAPPEDREGS_SHIFT);
Note: order could be a compile-time constant.
+            BUG_ON(get_order(sizeof(mapped_regs_t)) !=
+                   get_order_from_shift(XMAPPEDREGS_SHIFT));
As a consequence this should be an #error by adding a new entry in asm-offset.c
Earlier is better than latter!
Because sizeof(mapped_regs_t) is 4096, this couldn't be wrong now.

+            v->arch.privregs = alloc_xenheap_pages(order);
+            BUG_ON(v->arch.privregs == NULL);
+            memset(v->arch.privregs, 0, (1 << order) * PAGE_SIZE);
I'd prefer 1 << XMAPPEDREGS_SHIFT (more readable).
+            for (i = 0; i < (1 << order); i++)
+                share_xen_page_with_guest(virt_to_page(v->arch.privregs) + i,
+                                          d, XENSHARE_writable);
            }

Tristan.

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