[PATCH 5.14 102/849] powerpc/kvm: Fix kvm_use_magic_page

Greg Kroah-Hartman
2021-11-15T21:53:19Z

From: Andreas Gruenbacher <agruenba@redhat.com>

commit 0c8eb2884a42d992c7726539328b7d3568f22143 upstream.

When switching from __get_user to fault_in_pages_readable, commit
9f9eae5ce717 broke kvm_use_magic_page: like __get_user,
fault_in_pages_readable returns 0 on success.

Fixes: 9f9eae5ce717 ("powerpc/kvm: Prefer fault_in_pages_readable function")
Cc: stable@vger.kernel.org # v4.18+
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/powerpc/kernel/kvm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/powerpc/kernel/kvm.c
+++ b/arch/powerpc/kernel/kvm.c
@@ -669,7 +669,7 @@ static void __init kvm_use_magic_page(vo
on_each_cpu(kvm_map_magic_page, &features, 1);

/* Quick self-test to see if the mapping works */
- if (!fault_in_pages_readable((const char *)KVM_MAGIC_PAGE, sizeof(u32))) {
+ if (fault_in_pages_readable((const char *)KVM_MAGIC_PAGE, sizeof(u32))) {
kvm_patching_worked = false;
return;
}