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Subject[PATCH] x86/mm: Rewrite sme_populate_pgd() in a more sensible way
Date
sme_populate_pgd() open-codes a lot of things that are not needed to be
open-coded.

Let's rewrite it in a more stream-lined way.

This would also buy us boot-time switching between support between
paging modes, when rest of the pieces will be upstream.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---

The patch is only build tested. I don't have hardware. Tom, could you give it a try?

---
arch/x86/mm/mem_encrypt.c | 89 +++++++++++++++--------------------------------
1 file changed, 29 insertions(+), 60 deletions(-)

diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index d9a9e9fc75dd..16038f7472ca 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -489,73 +489,42 @@ static void __init sme_clear_pgd(pgd_t *pgd_base, unsigned long start,
static void __init *sme_populate_pgd(pgd_t *pgd_base, void *pgtable_area,
unsigned long vaddr, pmdval_t pmd_val)
{
- pgd_t *pgd_p;
- p4d_t *p4d_p;
- pud_t *pud_p;
- pmd_t *pmd_p;
-
- pgd_p = pgd_base + pgd_index(vaddr);
- if (native_pgd_val(*pgd_p)) {
- if (IS_ENABLED(CONFIG_X86_5LEVEL))
- p4d_p = (p4d_t *)(native_pgd_val(*pgd_p) & ~PTE_FLAGS_MASK);
- else
- pud_p = (pud_t *)(native_pgd_val(*pgd_p) & ~PTE_FLAGS_MASK);
- } else {
- pgd_t pgd;
-
- if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
- p4d_p = pgtable_area;
- memset(p4d_p, 0, sizeof(*p4d_p) * PTRS_PER_P4D);
- pgtable_area += sizeof(*p4d_p) * PTRS_PER_P4D;
-
- pgd = native_make_pgd((pgdval_t)p4d_p + PGD_FLAGS);
- } else {
- pud_p = pgtable_area;
- memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD);
- pgtable_area += sizeof(*pud_p) * PTRS_PER_PUD;
-
- pgd = native_make_pgd((pgdval_t)pud_p + PGD_FLAGS);
- }
- native_set_pgd(pgd_p, pgd);
+ pgd_t *pgd;
+ p4d_t *p4d;
+ pud_t *pud;
+ pmd_t *pmd;
+
+ pgd = pgd_base + pgd_index(vaddr);
+ if (pgd_none(*pgd)) {
+ p4d = pgtable_area;
+ memset(p4d, 0, sizeof(*p4d) * PTRS_PER_P4D);
+ pgtable_area += sizeof(*p4d) * PTRS_PER_P4D;
+ native_set_pgd(pgd, __pgd(PGD_FLAGS | __pa(p4d)));
}

- if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
- p4d_p += p4d_index(vaddr);
- if (native_p4d_val(*p4d_p)) {
- pud_p = (pud_t *)(native_p4d_val(*p4d_p) & ~PTE_FLAGS_MASK);
- } else {
- p4d_t p4d;
-
- pud_p = pgtable_area;
- memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD);
- pgtable_area += sizeof(*pud_p) * PTRS_PER_PUD;
-
- p4d = native_make_p4d((pudval_t)pud_p + P4D_FLAGS);
- native_set_p4d(p4d_p, p4d);
- }
+ p4d = p4d_offset(pgd, vaddr);
+ if (p4d_none(*p4d)) {
+ pud = pgtable_area;
+ memset(pud, 0, sizeof(*pud) * PTRS_PER_PUD);
+ pgtable_area += sizeof(*pud) * PTRS_PER_PUD;
+ native_set_p4d(p4d, __p4d(P4D_FLAGS | __pa(pud)));
}

- pud_p += pud_index(vaddr);
- if (native_pud_val(*pud_p)) {
- if (native_pud_val(*pud_p) & _PAGE_PSE)
- goto out;
-
- pmd_p = (pmd_t *)(native_pud_val(*pud_p) & ~PTE_FLAGS_MASK);
- } else {
- pud_t pud;
-
- pmd_p = pgtable_area;
- memset(pmd_p, 0, sizeof(*pmd_p) * PTRS_PER_PMD);
- pgtable_area += sizeof(*pmd_p) * PTRS_PER_PMD;
-
- pud = native_make_pud((pmdval_t)pmd_p + PUD_FLAGS);
- native_set_pud(pud_p, pud);
+ pud = pud_offset(p4d, vaddr);
+ if (pud_none(*pud)) {
+ pmd = pgtable_area;
+ memset(pmd, 0, sizeof(*pmd) * PTRS_PER_PMD);
+ pgtable_area += sizeof(*pmd) * PTRS_PER_PMD;
+ native_set_pud(pud, __pud(PUD_FLAGS | __pa(pmd)));
}
+ if (pud_large(*pud))
+ goto out;

- pmd_p += pmd_index(vaddr);
- if (!native_pmd_val(*pmd_p) || !(native_pmd_val(*pmd_p) & _PAGE_PSE))
- native_set_pmd(pmd_p, native_make_pmd(pmd_val));
+ pmd = pmd_offset(pud, vaddr);
+ if (pmd_large(*pmd))
+ goto out;

+ native_set_pmd(pmd, native_make_pmd(pmd_val));
out:
return pgtable_area;
}
--
2.15.0
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