Only intercept accesses to IO port 0xcf8 if there's at least one IOREQ
server, otherwise it makes no sense since the only code that uses the value
stored by hvm_access_cf8 is the IOREQ server.
Signed-off-by: Roger Pau Monné <roger....@citrix.com>
---
Cc: Jan Beulich <jbeul...@suse.com>
Cc: Andrew Cooper <andrew.coop...@citrix.com>
---
xen/arch/x86/hvm/hvm.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 28c6cd9..24c3d46 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -1141,6 +1141,13 @@ static int hvm_create_ioreq_server(struct domain *d,
domid_t domid,
if ( rc )
goto fail3;
+ /*
+ * We cannot fail after this point, or we risk registering the handler
+ * multiple times (there's no unregister function yet).
+ */
+ if ( list_empty(&d->arch.hvm_domain.ioreq_server.list) )
+ register_portio_handler(d, 0xcf8, 4, hvm_access_cf8);
+
list_add(&s->list_entry,
&d->arch.hvm_domain.ioreq_server.list);
@@ -1625,7 +1632,6 @@ int hvm_domain_initialise(struct domain *d)
pit_init(d, cpu_khz);
register_portio_handler(d, 0xe9, 1, hvm_print_line);
- register_portio_handler(d, 0xcf8, 4, hvm_access_cf8);
rc = hvm_funcs.domain_initialise(d);
if ( rc != 0 )
--
1.9.5 (Apple Git-50.3)
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