Commit-ID: 648babb7078c6310d2af5b8aa01f086030916968 Gitweb: http://git.kernel.org/tip/648babb7078c6310d2af5b8aa01f086030916968 Author: Tom Lendacky <thomas.lendacky@xxxxxxx> AuthorDate: Mon, 17 Jul 2017 16:10:22 -0500 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Tue, 18 Jul 2017 11:38:03 +0200 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@xxxxxxx> Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Brijesh Singh <brijesh.singh@xxxxxxx> Cc: Dave Young <dyoung@xxxxxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Jonathan Corbet <corbet@xxxxxxx> Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> Cc: Larry Woodman <lwoodman@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx> Cc: Michael S. Tsirkin <mst@xxxxxxxxxx> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Cc: Toshimitsu Kani <toshi.kani@xxxxxxx> Cc: kasan-dev@xxxxxxxxxxxxxxxx Cc: kvm@xxxxxxxxxxxxxxx Cc: linux-arch@xxxxxxxxxxxxxxx Cc: linux-doc@xxxxxxxxxxxxxxx Cc: linux-efi@xxxxxxxxxxxxxxx Cc: linux-mm@xxxxxxxxx Link: http://lkml.kernel.org/r/d112564053c3f2e86ca634a8d4fa4abc0eb53a6a.1500319216.git.thomas.lendacky@xxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- include/linux/dma-mapping.h | 13 +++++++++++++ lib/swiotlb.c | 3 +++ 2 files changed, 16 insertions(+) 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 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr) 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 @@ static inline int dma_set_mask(struct device *dev, u64 mask) { 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 @@ static inline int dma_set_coherent_mask(struct device *dev, u64 mask) { if (!dma_supported(dev, mask)) return -EIO; + + dma_check_mask(dev, mask); + dev->coherent_dma_mask = mask; return 0; } diff --git a/lib/swiotlb.c b/lib/swiotlb.c index 04ac91a..8c6c83e 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; -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html