KVM: SVM: Allow direct guest access to PC debug port
The PC debug port is used for IO delay and does not require emulation.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index fa17d6d..6cd6a50 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -378,7 +378,7 @@
int cpu;
struct page *iopm_pages;
struct page *msrpm_pages;
- void *msrpm_va;
+ void *iopm_va, *msrpm_va;
int r;
kvm_emulator_want_group7_invlpg();
@@ -387,8 +387,10 @@
if (!iopm_pages)
return -ENOMEM;
- memset(page_address(iopm_pages), 0xff,
- PAGE_SIZE * (1 << IOPM_ALLOC_ORDER));
+
+ iopm_va = page_address(iopm_pages);
+ memset(iopm_va, 0xff, PAGE_SIZE * (1 << IOPM_ALLOC_ORDER));
+ clear_bit(0x80, iopm_va); /* allow direct access to PC debug port */
iopm_base = page_to_pfn(iopm_pages) << PAGE_SHIFT;