On 1/21/21 10:46 AM, Janosch Frank wrote:
On 1/21/21 10:13 AM, 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>
---
MAINTAINERS | 1 +
lib/s390x/malloc_io.c | 70 +++++++++++++++++++++++++++++++++++++++++++
lib/s390x/malloc_io.h | 45 ++++++++++++++++++++++++++++
s390x/Makefile | 1 +
4 files changed, 117 insertions(+)
create mode 100644 lib/s390x/malloc_io.c
create mode 100644 lib/s390x/malloc_io.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 54124f6..89cb01e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -82,6 +82,7 @@ M: Thomas Huth <thuth@xxxxxxxxxx>
M: David Hildenbrand <david@xxxxxxxxxx>
M: Janosch Frank <frankja@xxxxxxxxxxxxx>
R: Cornelia Huck <cohuck@xxxxxxxxxx>
+R: Pierre Morel <pmorel@xxxxxxxxxxxxx>
If you're ok with the amount of mails you'll get then go ahead.
But I think maintainer file changes should always be in a separate patch.
L: kvm@xxxxxxxxxxxxxxx
L: linux-s390@xxxxxxxxxxxxxxx
F: s390x/*
diff --git a/lib/s390x/malloc_io.c b/lib/s390x/malloc_io.c
new file mode 100644
index 0000000..bfe8c6a
--- /dev/null
+++ b/lib/s390x/malloc_io.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0
I think we wanted to use:
/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * I/O page allocation
+ *
+ * Copyright (c) 2021 IBM Corp
+ *
+ * Authors:
+ * Pierre Morel <pmorel@xxxxxxxxxxxxx>
+ *
+ * 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>
+
+static int share_pages(void *p, int count)
+{
+ int i = 0;
+
+ for (i = 0; i < count; i++, p += PAGE_SIZE)
+ if (uv_set_shared((unsigned long)p))
+ return i;
+ return i;
+}
+
+static void unshare_pages(void *p, int count)
+{
+ int i;
+
+ for (i = count; i > 0; i--, p += PAGE_SIZE)
+ uv_remove_shared((unsigned long)p);
+}
+
+void *alloc_io_pages(int size, int flags)
+{
+ int order = (size >> PAGE_SHIFT);
+ void *p;
+ int n;
+
+ assert(size);
+
+ p = alloc_pages_flags(order, AREA_DMA31 | flags);
+ if (!p || !test_facility(158))
+ return p;
+
+ n = share_pages(p, 1 << order);
+ if (n == 1 << order)
+ return p;
+
+ unshare_pages(p, n);
+ free_pages(p);
+ return NULL;
+}
+
+void free_io_pages(void *p, int size)
+{
+ int order = size >> PAGE_SHIFT;
+
+ assert(IS_ALIGNED((uintptr_t)p, PAGE_SIZE));
+
+ if (test_facility(158))
+ unshare_pages(p, 1 << order);
I have a lib file in the making that will let you check UV features like
test_facility(). When that's ready I'm gonna check for unshare here.
OK.
On share_pages the rc is enough I suppose.
--
Pierre Morel
IBM Lab Boeblingen
