Re: [kvm-unit-tests PATCH v4 2/3] s390x: define UV compatible I/O allocation

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





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



[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Kernel Development]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite Info]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Linux Media]     [Device Mapper]

  Powered by Linux