On Wed, Jul 10, 2019 at 07:01:19PM +0000, Lendacky, Thomas wrote:
> @@ -351,6 +355,32 @@ bool sev_active(void)
> }
> EXPORT_SYMBOL(sev_active);
>
> +/* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED
> */
> +bool force_dma_unencrypted(struct device *dev)
> +{
> + /*
> + * For SEV, all DMA must be to unencrypted addresses.
> + */
> + if (sev_active())
> + return true;
> +
> + /*
> + * For SME, all DMA must be to unencrypted addresses if the
> + * device does not support DMA to addresses that include the
> + * encryption mask.
> + */
> + if (sme_active()) {
> + u64 dma_enc_mask = DMA_BIT_MASK(__ffs64(sme_me_mask));
> + u64 dma_dev_mask = min_not_zero(dev->coherent_dma_mask,
> + dev->bus_dma_mask);
> +
> + if (dma_dev_mask <= dma_enc_mask)
> + return true;
Hm. What is wrong with the dev mask being equal to enc mask? IIUC, it
means that device mask is wide enough to cover encryption bit, doesn't it?
> + }
> +
> + return false;
> +}
--
Kirill A. Shutemov
