On 19/01/2021 20.52, Pierre Morel wrote:
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.
Janosch recently started to introduce SPDX identifieres to the s390x code,
so I think it would be good to use them here, too.
+ * 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);
Apart from the assert() statement, the size parameter seems to be completely
unused. It's also weird to have the function named alloc_something_page()
and then have a parameter that takes bytes. Thus I'd suggest to either drop
the size parameter completely, or to rename the function to alloc_io_mem and
then to alloc multiple pages below in case the size is bigger than
PAGE_SIZE. Or maybe even to name the function alloc_io_pages and then use
"int num_pages" as a parameter, allowing to allocate multiple pages at once?
+
+ 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.
+ */
Please also add SPDX license information here.
Thomas
