On 1/24/2018 10:36 AM, Kirill A. Shutemov wrote:
> sme_pgtable_calc() is unnecessary complex. It can be re-written in a
> more stream-lined way.
>
> As a side effect, we would get the code ready to boot-time switching
> between paging modes.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Reviewed-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
> ---
> arch/x86/mm/mem_encrypt_identity.c | 42 +++++++++++---------------------------
> 1 file changed, 12 insertions(+), 30 deletions(-)
>
> diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c
> index 69635a02ce9e..613686cc56ae 100644
> --- a/arch/x86/mm/mem_encrypt_identity.c
> +++ b/arch/x86/mm/mem_encrypt_identity.c
> @@ -230,8 +230,7 @@ static void __init sme_map_range_decrypted_wp(struct sme_populate_pgd_data *ppd)
>
> static unsigned long __init sme_pgtable_calc(unsigned long len)
> {
> - unsigned long p4d_size, pud_size, pmd_size, pte_size;
> - unsigned long total;
> + unsigned long entries = 0, tables = 0;
>
> /*
> * Perform a relatively simplistic calculation of the pagetable
> @@ -245,42 +244,25 @@ static unsigned long __init sme_pgtable_calc(unsigned long len)
> * Incrementing the count for each covers the case where the addresses
> * cross entries.
> */
> - if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
> - p4d_size = (ALIGN(len, PGDIR_SIZE) / PGDIR_SIZE) + 1;
> - p4d_size *= sizeof(p4d_t) * PTRS_PER_P4D;
> - pud_size = (ALIGN(len, P4D_SIZE) / P4D_SIZE) + 1;
> - pud_size *= sizeof(pud_t) * PTRS_PER_PUD;
> - } else {
> - p4d_size = 0;
> - pud_size = (ALIGN(len, PGDIR_SIZE) / PGDIR_SIZE) + 1;
> - pud_size *= sizeof(pud_t) * PTRS_PER_PUD;
> - }
> - pmd_size = (ALIGN(len, PUD_SIZE) / PUD_SIZE) + 1;
> - pmd_size *= sizeof(pmd_t) * PTRS_PER_PMD;
> - pte_size = 2 * sizeof(pte_t) * PTRS_PER_PTE;
>
> - total = p4d_size + pud_size + pmd_size + pte_size;
> + /* PGDIR_SIZE is equal to P4D_SIZE on 4-level machine. */
> + if (PTRS_PER_P4D > 1)
> + entries += (DIV_ROUND_UP(len, PGDIR_SIZE) + 1) * sizeof(p4d_t) * PTRS_PER_P4D;
> + entries += (DIV_ROUND_UP(len, P4D_SIZE) + 1) * sizeof(pud_t) * PTRS_PER_PUD;
> + entries += (DIV_ROUND_UP(len, PUD_SIZE) + 1) * sizeof(pmd_t) * PTRS_PER_PMD;
> + entries += 2 * sizeof(pte_t) * PTRS_PER_PTE;
>
> /*
> * Now calculate the added pagetable structures needed to populate
> * the new pagetables.
> */
> - if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
> - p4d_size = ALIGN(total, PGDIR_SIZE) / PGDIR_SIZE;
> - p4d_size *= sizeof(p4d_t) * PTRS_PER_P4D;
> - pud_size = ALIGN(total, P4D_SIZE) / P4D_SIZE;
> - pud_size *= sizeof(pud_t) * PTRS_PER_PUD;
> - } else {
> - p4d_size = 0;
> - pud_size = ALIGN(total, PGDIR_SIZE) / PGDIR_SIZE;
> - pud_size *= sizeof(pud_t) * PTRS_PER_PUD;
> - }
> - pmd_size = ALIGN(total, PUD_SIZE) / PUD_SIZE;
> - pmd_size *= sizeof(pmd_t) * PTRS_PER_PMD;
>
> - total += p4d_size + pud_size + pmd_size;
> + if (PTRS_PER_P4D > 1)
> + tables += DIV_ROUND_UP(entries, PGDIR_SIZE) * sizeof(p4d_t) * PTRS_PER_P4D;
> + tables += DIV_ROUND_UP(entries, P4D_SIZE) * sizeof(pud_t) * PTRS_PER_PUD;
> + tables += DIV_ROUND_UP(entries, PUD_SIZE) * sizeof(pmd_t) * PTRS_PER_PMD;
>
> - return total;
> + return entries + tables;
> }
>
> void __init __nostackprotector sme_encrypt_kernel(struct boot_params *bp)
>
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