To centralize the memory allocation for I/O we define
the alloc_io_page/free_io_page functions which share the I/O
memory with the host in case the guest runs with
protected virtualization.
Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
---
lib/s390x/malloc_io.c | 50 +++++++++++++++++++++++++++++++++++++++++++
lib/s390x/malloc_io.h | 18 ++++++++++++++++
s390x/Makefile | 1 +
3 files changed, 69 insertions(+)
create mode 100644 lib/s390x/malloc_io.c
create mode 100644 lib/s390x/malloc_io.h
diff --git a/lib/s390x/malloc_io.c b/lib/s390x/malloc_io.c
new file mode 100644
index 0000000..2a946e0
--- /dev/null
+++ b/lib/s390x/malloc_io.c
@@ -0,0 +1,50 @@
+/*
+ * I/O page allocation
+ *
+ * Copyright (c) 2021 IBM Corp
+ *
+ * Authors:
+ * Pierre Morel <pmorel@xxxxxxxxxxxxx>
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2.
+ *
+ * Using this interface provide host access to the allocated pages in
+ * case the guest is a secure guest.
+ * This is needed for I/O buffers.
+ *
+ */
+#include <libcflat.h>
+#include <asm/page.h>
+#include <asm/uv.h>
+#include <malloc_io.h>
+#include <alloc_page.h>
+#include <asm/facility.h>
+
+void *alloc_io_page(int size)
+{
+ void *p;
+
+ assert(size <= PAGE_SIZE);
+
+ p = alloc_pages_flags(1, AREA_DMA31);
+ if (!p)
+ return NULL;
+ memset(p, 0, PAGE_SIZE);
+
+ if (!test_facility(158))
+ return p;
+
+ if (uv_set_shared((unsigned long)p) == 0)
+ return p;
+
+ free_pages(p);
+ return NULL;
+}
+
+void free_io_page(void *p)
+{
+ if (test_facility(158))
+ uv_remove_shared((unsigned long)p);
+ free_pages(p);
+}
diff --git a/lib/s390x/malloc_io.h b/lib/s390x/malloc_io.h
new file mode 100644
index 0000000..f780191
--- /dev/null
+++ b/lib/s390x/malloc_io.h
@@ -0,0 +1,18 @@
+/*
+ * I/O allocations
+ *
+ * Copyright (c) 2021 IBM Corp
+ *
+ * Authors:
+ * Pierre Morel <pmorel@xxxxxxxxxxxxx>
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2.
+ */
+#ifndef _S390X_MALLOC_IO_H_
+#define _S390X_MALLOC_IO_H_
+
+void *alloc_io_page(int size);
+void free_io_page(void *p);
+
+#endif /* _S390X_MALLOC_IO_H_ */
diff --git a/s390x/Makefile b/s390x/Makefile
index b079a26..4b6301c 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -63,6 +63,7 @@ cflatobjs += lib/s390x/smp.o
cflatobjs += lib/s390x/vm.o
cflatobjs += lib/s390x/css_dump.o
cflatobjs += lib/s390x/css_lib.o
+cflatobjs += lib/s390x/malloc_io.o
OBJDIRS += lib/s390x
--
2.17.1
