[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] Re: [PATCH] Make page_find() return 0 for too-large add
From: |
Eduardo Habkost |
Subject: |
Re: [Qemu-devel] Re: [PATCH] Make page_find() return 0 for too-large addresses |
Date: |
Fri, 12 Sep 2008 17:44:05 -0300 |
User-agent: |
Mutt/1.5.18 (2008-05-17) |
On Fri, Sep 12, 2008 at 05:14:06PM -0300, Eduardo Habkost wrote:
> On Fri, Sep 12, 2008 at 02:50:33PM -0500, Anthony Liguori wrote:
> > Eduardo Habkost wrote:
> >> On some cases, such as under KVM, tb_invalidate_phys_page_range()
> >> may be called for large addresses, when qemu is configured to more than
> >> 4GB of RAM.
> >>
> >> On these cases, qemu was crashing because it was using an index too
> >> large for l1_map[], that supports only 32-bit addresses when compiling
> >> without CONFIG_USER_ONLY.
> >>
<snip>
>
> BTW, I've just noticed page_find_alloc() has this:
>
> #if TARGET_LONG_BITS > 32
> /* Host memory outside guest VM. For 32-bit targets we have already
> excluded high addresses. */
> if (index > ((target_ulong)L2_SIZE * L1_SIZE))
> return NULL;
> #endif
>
> So, we can just use a similar check on page_find().
New patch, reusing the range check from page_find_alloc() on
page_find(). Untested.
Signed-off-by: Eduardo Habkost <address@hidden>
---
Index: qemu/exec.c
===================================================================
--- qemu/exec.c (revisão 5200)
+++ qemu/exec.c (cópia de trabalho)
@@ -279,17 +279,24 @@ static void page_init(void)
#endif
}
-static inline PageDesc *page_find_alloc(target_ulong index)
+static inline PageDesc **page_l1_map(target_ulong index)
{
- PageDesc **lp, *p;
-
#if TARGET_LONG_BITS > 32
/* Host memory outside guest VM. For 32-bit targets we have already
excluded high addresses. */
if (index > ((target_ulong)L2_SIZE * L1_SIZE))
return NULL;
#endif
- lp = &l1_map[index >> L2_BITS];
+ return &l1_map[index >> L2_BITS];
+}
+
+static inline PageDesc *page_find_alloc(target_ulong index)
+{
+ PageDesc **lp, *p;
+ lp = page_l1_map(index);
+ if (!lp)
+ return NULL;
+
p = *lp;
if (!p) {
/* allocate if not found */
@@ -316,9 +323,12 @@ static inline PageDesc *page_find_alloc(
static inline PageDesc *page_find(target_ulong index)
{
- PageDesc *p;
+ PageDesc **lp, *p;
+ lp = page_l1_map(index);
+ if (!lp)
+ return NULL;
- p = l1_map[index >> L2_BITS];
+ p = *lp;
if (!p)
return 0;
return p + (index & (L2_SIZE - 1));
--
Eduardo