From mboxrd@z Thu Jan 1 00:00:00 1970 From: Borislav Petkov Subject: Re: [PATCH v5 23/32] swiotlb: Add warnings for use of bounce buffers with SME Date: Tue, 16 May 2017 16:52:09 +0200 Message-ID: <20170516145209.ltbmaq3a2teqr2uv@pd.tnic> References: <20170418211612.10190.82788.stgit@tlendack-t1.amdoffice.net> <20170418212019.10190.24034.stgit@tlendack-t1.amdoffice.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Content-Disposition: inline In-Reply-To: <20170418212019.10190.24034.stgit@tlendack-t1.amdoffice.net> Sender: owner-linux-mm@kvack.org To: Tom Lendacky Cc: linux-arch@vger.kernel.org, linux-efi@vger.kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, x86@kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, iommu@lists.linux-foundation.org, Rik van Riel , Radim =?utf-8?B?S3LEjW3DocWZ?= , Toshimitsu Kani , Arnd Bergmann , Jonathan Corbet , Matt Fleming , "Michael S. Tsirkin" , Joerg Roedel , Konrad Rzeszutek Wilk , Paolo Bonzini , Larry Woodman , Brijesh Singh , Ingo Molnar , Andy Lutomirski , "H. Peter Anvin" , Andrey Ryabinin , Alexander List-Id: linux-efi@vger.kernel.org On Tue, Apr 18, 2017 at 04:20:19PM -0500, Tom Lendacky wrote: > 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. > > Signed-off-by: Tom Lendacky > --- > arch/x86/include/asm/mem_encrypt.h | 11 +++++++++++ > include/linux/dma-mapping.h | 11 +++++++++++ > include/linux/mem_encrypt.h | 6 ++++++ > lib/swiotlb.c | 3 +++ > 4 files changed, 31 insertions(+) > > diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h > index 0637b4b..b406df2 100644 > --- a/arch/x86/include/asm/mem_encrypt.h > +++ b/arch/x86/include/asm/mem_encrypt.h > @@ -26,6 +26,11 @@ static inline bool sme_active(void) > return !!sme_me_mask; > } > > +static inline u64 sme_dma_mask(void) > +{ > + return ((u64)sme_me_mask << 1) - 1; > +} > + > void __init sme_early_encrypt(resource_size_t paddr, > unsigned long size); > void __init sme_early_decrypt(resource_size_t paddr, > @@ -50,6 +55,12 @@ static inline bool sme_active(void) > { > return false; > } > + > +static inline u64 sme_dma_mask(void) > +{ > + return 0ULL; > +} > + > #endif > > static inline void __init sme_early_encrypt(resource_size_t paddr, > diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h > index 0977317..f825870 100644 > --- a/include/linux/dma-mapping.h > +++ b/include/linux/dma-mapping.h > @@ -10,6 +10,7 @@ > #include > #include > #include > +#include > > /** > * List of possible attributes associated with a DMA mapping. The semantics > @@ -577,6 +578,11 @@ static inline int dma_set_mask(struct device *dev, u64 mask) > > if (!dev->dma_mask || !dma_supported(dev, mask)) > return -EIO; > + > + if (sme_active() && (mask < sme_dma_mask())) > + dev_warn_ratelimited(dev, > + "SME is active, device will require DMA bounce buffers\n"); Bah, no need to break that line - just let it stick out. Ditto for the others. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org