# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1207901921 -3600
# Node ID f39b20085a3d18ff4801fafe1f4b5d029709b971
# Parent b1339df987e90878b23a97d911bfed90cf893cfd
x86/64 compat: Replace hypervisor BUG_ON() with a cleaner hypercall failure.
While trying to run a 32-bit PV domU on a 64-bit hypervisor, I
triggered an assert in the hypervisor. The assert dealt with the
maximum number of grants that a domU can have. I made the hypervisor
a bit more graceful by returning an error rather than asserting.
Signed-off-by: Michael Abd-El-Malek <mabdelmalek@xxxxxxx>
xen-unstable changeset: 17438:115a1720e976a184b2c044541a99b413b2bf844e
xen-unstable date: Fri Apr 11 09:10:58 2008 +0100
---
xen/common/compat/grant_table.c | 20 ++++++++++++++++----
1 files changed, 16 insertions(+), 4 deletions(-)
diff -r b1339df987e9 -r f39b20085a3d xen/common/compat/grant_table.c
--- a/xen/common/compat/grant_table.c Fri Apr 11 09:18:08 2008 +0100
+++ b/xen/common/compat/grant_table.c Fri Apr 11 09:18:41 2008 +0100
@@ -109,12 +109,24 @@ int compat_grant_table_op(unsigned int c
rc = -EFAULT;
else
{
- BUG_ON((COMPAT_ARG_XLAT_SIZE - sizeof(*nat.setup)) /
sizeof(*nat.setup->frame_list.p) < max_nr_grant_frames);
+ unsigned int max_frame_list_size_in_page =
+ (COMPAT_ARG_XLAT_SIZE - sizeof(*nat.setup)) /
+ sizeof(*nat.setup->frame_list.p);
+ if ( max_frame_list_size_in_page < max_nr_grant_frames )
+ {
+ gdprintk(XENLOG_WARNING,
+ "max_nr_grant_frames is too large (%u,%u)\n",
+ max_nr_grant_frames, max_frame_list_size_in_page);
+ rc = -EINVAL;
+ }
+ else
+ {
#define XLAT_gnttab_setup_table_HNDL_frame_list(_d_, _s_) \
- set_xen_guest_handle((_d_)->frame_list, (unsigned long
*)(nat.setup + 1))
- XLAT_gnttab_setup_table(nat.setup, &cmp.setup);
+ set_xen_guest_handle((_d_)->frame_list, (unsigned long
*)(nat.setup + 1))
+ XLAT_gnttab_setup_table(nat.setup, &cmp.setup);
#undef XLAT_gnttab_setup_table_HNDL_frame_list
- rc = gnttab_setup_table(guest_handle_cast(nat.uop,
gnttab_setup_table_t), 1);
+ rc = gnttab_setup_table(guest_handle_cast(nat.uop,
gnttab_setup_table_t), 1);
+ }
}
if ( rc == 0 )
{
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