With upcoming patches, normal guests might touch secure pages.
This patch extends the existing exception handler to convert the pages
to non secure also when the exception is triggered by a normal guest.
This can happen for example when a secure guest reboots; the first
stage of a secure guest is non secure, and in general a secure guest
can reboot into non-secure mode.
If the secure memory of the previous boot has not been cleared up
completely yet, a non-secure guest might touch secure memory, which
will need to be handled properly.
Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
---
arch/s390/mm/fault.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index eb68b4f36927..b89d625ea2ec 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -767,6 +767,7 @@ void do_secure_storage_access(struct pt_regs *regs)
struct vm_area_struct *vma;
struct mm_struct *mm;
struct page *page;
+ struct gmap *gmap;
int rc;
/*
@@ -796,6 +797,16 @@ void do_secure_storage_access(struct pt_regs *regs)
}
switch (get_fault_type(regs)) {
+ case GMAP_FAULT:
+ gmap = (struct gmap *)S390_lowcore.gmap;
+ /*
+ * Very unlikely, but if it happens, simply try again.
+ * The next attempt will trigger a different exception.
+ */
+ addr = __gmap_translate(gmap, addr);
+ if (addr == -EFAULT)
+ break;
+ fallthrough;
case USER_FAULT:
mm = current->mm;
mmap_read_lock(mm);
@@ -824,7 +835,6 @@ void do_secure_storage_access(struct pt_regs *regs)
if (rc)
BUG();
break;
- case GMAP_FAULT:
default:
do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP);
WARN_ON_ONCE(1);
--
2.31.1
