swiotlb: Add warnings for use of bounce buffers with SME
Add warnings to let the user know when bounce buffers are being used for
DMA when SME is active. Since the bounce buffers are not in encrypted
memory, these notifications are to allow the user to determine some
appropriate action - if necessary. Actions can range from utilizing an
IOMMU, replacing the device with another device that can support 64-bit
DMA, ignoring the message if the device isn't used much, etc.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Toshimitsu Kani <toshi.kani@hpe.com>
Cc: kasan-dev@googlegroups.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-efi@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/d112564053c3f2e86ca634a8d4fa4abc0eb53a6a.1500319216.git.thomas.lendacky@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 843ab86..fce2369 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -10,6 +10,7 @@
#include <linux/scatterlist.h>
#include <linux/kmemcheck.h>
#include <linux/bug.h>
+#include <linux/mem_encrypt.h>
/**
* List of possible attributes associated with a DMA mapping. The semantics
@@ -548,6 +549,12 @@
return 0;
}
+static inline void dma_check_mask(struct device *dev, u64 mask)
+{
+ if (sme_active() && (mask < (((u64)sme_get_me_mask() << 1) - 1)))
+ dev_warn(dev, "SME is active, device will require DMA bounce buffers\n");
+}
+
static inline int dma_supported(struct device *dev, u64 mask)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
@@ -564,6 +571,9 @@
{
if (!dev->dma_mask || !dma_supported(dev, mask))
return -EIO;
+
+ dma_check_mask(dev, mask);
+
*dev->dma_mask = mask;
return 0;
}
@@ -583,6 +593,9 @@
{
if (!dma_supported(dev, mask))
return -EIO;
+
+ dma_check_mask(dev, mask);
+
dev->coherent_dma_mask = mask;
return 0;
}