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authorTom Lendacky <thomas.lendacky@amd.com>2017-07-17 17:10:22 -0400
committerIngo Molnar <mingo@kernel.org>2017-07-18 05:38:03 -0400
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,
507 if (no_iotlb_memory) 507 if (no_iotlb_memory)
508 panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer"); 508 panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
509 509
510 if (sme_active())
511 pr_warn_once("SME is active and system is using DMA bounce buffers\n");
512
510 mask = dma_get_seg_boundary(hwdev); 513 mask = dma_get_seg_boundary(hwdev);
511 514
512 tbl_dma_addr &= mask; 515 tbl_dma_addr &= mask;