Messages in this thread | | | Date | Sun, 22 May 2022 18:04:51 -0700 (PDT) | From | David Rientjes <> | Subject | Re: [PATCH] dma-direct: Don't over-decrypt memory |
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On Fri, 20 May 2022, Robin Murphy wrote:
> The original x86 sev_alloc() only called set_memory_decrypted() on > memory returned by alloc_pages_node(), so the page order calculation > fell out of that logic. However, the common dma-direct code has several > potential allocators, not all of which are guaranteed to round up the > underlying allocation to a power-of-two size, so carrying over that > calculation for the encryption/decryption size was a mistake. Fix it by > rounding to a *number* of pages, rather than an order. > > Until recently there was an even worse interaction with DMA_DIRECT_REMAP > where we could have ended up decrypting part of the next adjacent > vmalloc area, only averted by no architecture actually supporting both > configs at once. Don't ask how I found that one out... > > CC: stable@vger.kernel.org > Fixes: c10f07aa27da ("dma/direct: Handle force decryption for DMA coherent buffers in common code") > Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: David Rientjes <rientjes@google.com>
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