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authorTom Lendacky <thomas.lendacky@amd.com>2017-07-17 16:10:22 -0500
committerIngo Molnar <mingo@kernel.org>2017-07-18 11:38:03 +0200
commit648babb7078c6310d2af5b8aa01f086030916968 (patch)
treec386725f2a5dbd748b5918e638a67e45e4d3e59b /lib/swiotlb.c
parentc7753208a94c73d5beb1e4bd843081d6dc7d4678 (diff)
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>
Diffstat (limited to 'lib/swiotlb.c')
-rw-r--r--lib/swiotlb.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 04ac91acf193..8c6c83ef57a4 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -507,6 +507,9 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
if (no_iotlb_memory)
panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
+ if (sme_active())
+ pr_warn_once("SME is active and system is using DMA bounce buffers\n");
+
mask = dma_get_seg_boundary(hwdev);
tbl_dma_addr &= mask;