On Mon, Aug 22, 2016 at 05:38:20PM -0500, Tom Lendacky wrote:
> Add support to the AMD IOMMU driver to set the memory encryption mask if
> memory encryption is enabled.
>
> Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
> ---
> arch/x86/include/asm/mem_encrypt.h | 2 ++
> arch/x86/mm/mem_encrypt.c | 5 +++++
> drivers/iommu/amd_iommu.c | 10 ++++++++++
> 3 files changed, 17 insertions(+)
>
> diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
> index 384fdfb..e395729 100644
> --- a/arch/x86/include/asm/mem_encrypt.h
> +++ b/arch/x86/include/asm/mem_encrypt.h
> @@ -36,6 +36,8 @@ void __init sme_early_init(void);
> /* Architecture __weak replacement functions */
> void __init mem_encrypt_init(void);
>
> +unsigned long amd_iommu_get_me_mask(void);
> +
> unsigned long swiotlb_get_me_mask(void);
> void swiotlb_set_mem_dec(void *vaddr, unsigned long size);
>
> diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
> index 6b2e8bf..2f28d87 100644
> --- a/arch/x86/mm/mem_encrypt.c
> +++ b/arch/x86/mm/mem_encrypt.c
> @@ -185,6 +185,11 @@ void __init mem_encrypt_init(void)
> swiotlb_clear_encryption();
> }
>
> +unsigned long amd_iommu_get_me_mask(void)
> +{
> + return sme_me_mask;
> +}
> +
> unsigned long swiotlb_get_me_mask(void)
> {
> return sme_me_mask;
> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> index 96de97a..63995e3 100644
> --- a/drivers/iommu/amd_iommu.c
> +++ b/drivers/iommu/amd_iommu.c
> @@ -166,6 +166,15 @@ struct dma_ops_domain {
> static struct iova_domain reserved_iova_ranges;
> static struct lock_class_key reserved_rbtree_key;
>
> +/*
> + * Support for memory encryption. If memory encryption is supported, then an
> + * override to this function will be provided.
> + */
> +unsigned long __weak amd_iommu_get_me_mask(void)
> +{
> + return 0;
> +}
So instead of adding a function each time which returns sme_me_mask
for each user it has, why don't you add a single function which
returns sme_me_mask in mem_encrypt.c and add an inline in the header
mem_encrypt.h which returns 0 for the !CONFIG_AMD_MEM_ENCRYPT case.
This all is still funny because we access sme_me_mask directly for the
different KERNEL_* masks but then you're adding an accessor function.
So what you should do instead, IMHO, is either hide sme_me_mask
altogether and use the accessor functions only (not sure if that would
work in all cases) or expose sme_me_mask unconditionally and have it be
0 if CONFIG_AMD_MEM_ENCRYPT is not enabled so that it just works.
Or is there a third, more graceful variant?
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
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