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SubjectRe: [PATCH v2 3/5] x86/mm: Centralize PMD flags in sme_encrypt_kernel()
On Thu, Dec 21, 2017 at 04:03:12PM -0600, Tom Lendacky wrote:
> In preparation for encrypting more than just the kernel during early
> boot processing, centralize the use of the PMD flag settings based
> on the type of mapping desired. When 4KB aligned encryption is added,
> this will allow either PTE flags or large page PMD flags to be used
> without requiring the caller to adjust.
>
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
> arch/x86/mm/mem_encrypt.c | 131 ++++++++++++++++++++++++++-------------------
> 1 file changed, 77 insertions(+), 54 deletions(-)
>
> diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
> index 5a20696..9b180f8 100644
> --- a/arch/x86/mm/mem_encrypt.c
> +++ b/arch/x86/mm/mem_encrypt.c
> @@ -468,31 +468,40 @@ struct sme_populate_pgd_data {
> void *pgtable_area;
> pgd_t *pgd;
>
> - pmdval_t pmd_val;
> + pmdval_t pmd_flags;
> + unsigned long paddr;
> +
> unsigned long vaddr;
> + unsigned long vaddr_end;
> };
>
> -static void __init sme_clear_pgd(pgd_t *pgd_base, unsigned long start,
> - unsigned long end)
> +static void __init sme_clear_pgd(struct sme_populate_pgd_data *ppd)
> {
> unsigned long pgd_start, pgd_end, pgd_size;
> pgd_t *pgd_p;
>
> - pgd_start = start & PGDIR_MASK;
> - pgd_end = end & PGDIR_MASK;
> + pgd_start = ppd->vaddr & PGDIR_MASK;
> + pgd_end = ppd->vaddr_end & PGDIR_MASK;
>
> pgd_size = (((pgd_end - pgd_start) / PGDIR_SIZE) + 1);
> pgd_size *= sizeof(pgd_t);

This is a strange way of writing this. I'd expect:

pgd_size = (((pgd_end - pgd_start) / PGDIR_SIZE) + 1) * sizeof(pgd_t);

>
> - pgd_p = pgd_base + pgd_index(start);
> + pgd_p = ppd->pgd + pgd_index(ppd->vaddr);
>
> memset(pgd_p, 0, pgd_size);
> }
>
> -#define PGD_FLAGS _KERNPG_TABLE_NOENC
> -#define P4D_FLAGS _KERNPG_TABLE_NOENC
> -#define PUD_FLAGS _KERNPG_TABLE_NOENC
> -#define PMD_FLAGS (__PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL)
> +#define PGD_FLAGS _KERNPG_TABLE_NOENC
> +#define P4D_FLAGS _KERNPG_TABLE_NOENC
> +#define PUD_FLAGS _KERNPG_TABLE_NOENC
> +
> +#define PMD_FLAGS_LARGE (__PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL)
> +
> +#define PMD_FLAGS_DEC PMD_FLAGS_LARGE
> +#define PMD_FLAGS_DEC_WP ((PMD_FLAGS_DEC & ~_PAGE_CACHE_MASK) | \
> + (_PAGE_PAT | _PAGE_PWT))
> +
> +#define PMD_FLAGS_ENC (PMD_FLAGS_LARGE | _PAGE_ENC)
>
> static void __init sme_populate_pgd_large(struct sme_populate_pgd_data *ppd)
> {
> @@ -561,7 +570,36 @@ static void __init sme_populate_pgd_large(struct sme_populate_pgd_data *ppd)
>
> pmd_p += pmd_index(ppd->vaddr);
> if (!native_pmd_val(*pmd_p) || !(native_pmd_val(*pmd_p) & _PAGE_PSE))
> - native_set_pmd(pmd_p, native_make_pmd(ppd->pmd_val));
> + native_set_pmd(pmd_p,
> + native_make_pmd(ppd->paddr | ppd->pmd_flags));

Never do those ugly line breaks. Just let it stick out.

Otherwise, sme_encrypt_kernel() is starting to look quite readable :)

--
Regards/Gruss,
Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.

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