From aad983913d77af2c3394f29b88d7bb75ebd7d172 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Wed, 31 Jan 2018 16:54:03 +0300 Subject: [PATCH] x86/mm/encrypt: Simplify sme_populate_pgd() and sme_populate_pgd_large() sme_populate_pgd() and sme_populate_pgd_large() operate on the identity mapping, which means they want virtual addresses to be equal to physical one, without PAGE_OFFSET shift. We also need to avoid paravirtualization call there. Getting this done is tricky. We cannot use usual page table helpers. It forces us to open-code a lot of things. It makes code ugly and hard to modify. We can get it work with the page table helpers, but it requires few preprocessor tricks. - Define __pa() and __va() to be compatible with identity mapping. - Undef CONFIG_PARAVIRT and CONFIG_PARAVIRT_SPINLOCKS before including any file. This way we can avoid paravirtualization calls. Now we can user normal page table helpers just fine. Tested-by: Tom Lendacky Signed-off-by: Kirill A. Shutemov Reviewed-by: Tom Lendacky Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180131135404.40692-3-kirill.shutemov@linux.intel.com Signed-off-by: Ingo Molnar --- arch/x86/mm/mem_encrypt_identity.c | 159 +++++++++++++---------------- 1 file changed, 72 insertions(+), 87 deletions(-) diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c index a28978a37bfa..4b6a2e3098c5 100644 --- a/arch/x86/mm/mem_encrypt_identity.c +++ b/arch/x86/mm/mem_encrypt_identity.c @@ -12,6 +12,24 @@ #define DISABLE_BRANCH_PROFILING +/* + * Since we're dealing with identity mappings, physical and virtual + * addresses are the same, so override these defines which are ultimately + * used by the headers in misc.h. + */ +#define __pa(x) ((unsigned long)(x)) +#define __va(x) ((void *)((unsigned long)(x))) + +/* + * Special hack: we have to be careful, because no indirections are + * allowed here, and paravirt_ops is a kind of one. As it will only run in + * baremetal anyway, we just keep it from happening. (This list needs to + * be extended when new paravirt and debugging variants are added.) + */ +#undef CONFIG_PARAVIRT +#undef CONFIG_PARAVIRT_SPINLOCKS + +#include #include #include @@ -73,116 +91,83 @@ static void __init sme_clear_pgd(struct sme_populate_pgd_data *ppd) memset(pgd_p, 0, pgd_size); } -static pmd_t __init *sme_prepare_pgd(struct sme_populate_pgd_data *ppd) +static pud_t __init *sme_prepare_pgd(struct sme_populate_pgd_data *ppd) { - pgd_t *pgd_p; - p4d_t *p4d_p; - pud_t *pud_p; - pmd_t *pmd_p; - - pgd_p = ppd->pgd + pgd_index(ppd->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 = ppd->pgtable_area; - memset(p4d_p, 0, sizeof(*p4d_p) * PTRS_PER_P4D); - ppd->pgtable_area += sizeof(*p4d_p) * PTRS_PER_P4D; - - pgd = native_make_pgd((pgdval_t)p4d_p + PGD_FLAGS); - } else { - pud_p = ppd->pgtable_area; - memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD); - ppd->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 = ppd->pgd + pgd_index(ppd->vaddr); + if (pgd_none(*pgd)) { + p4d = ppd->pgtable_area; + memset(p4d, 0, sizeof(*p4d) * PTRS_PER_P4D); + ppd->pgtable_area += sizeof(*p4d) * PTRS_PER_P4D; + set_pgd(pgd, __pgd(PGD_FLAGS | __pa(p4d))); } - if (IS_ENABLED(CONFIG_X86_5LEVEL)) { - p4d_p += p4d_index(ppd->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 = ppd->pgtable_area; - memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD); - ppd->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, ppd->vaddr); + if (p4d_none(*p4d)) { + pud = ppd->pgtable_area; + memset(pud, 0, sizeof(*pud) * PTRS_PER_PUD); + ppd->pgtable_area += sizeof(*pud) * PTRS_PER_PUD; + set_p4d(p4d, __p4d(P4D_FLAGS | __pa(pud))); } - pud_p += pud_index(ppd->vaddr); - if (native_pud_val(*pud_p)) { - if (native_pud_val(*pud_p) & _PAGE_PSE) - return NULL; - - pmd_p = (pmd_t *)(native_pud_val(*pud_p) & ~PTE_FLAGS_MASK); - } else { - pud_t pud; - - pmd_p = ppd->pgtable_area; - memset(pmd_p, 0, sizeof(*pmd_p) * PTRS_PER_PMD); - ppd->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, ppd->vaddr); + if (pud_none(*pud)) { + pmd = ppd->pgtable_area; + memset(pmd, 0, sizeof(*pmd) * PTRS_PER_PMD); + ppd->pgtable_area += sizeof(*pmd) * PTRS_PER_PMD; + set_pud(pud, __pud(PUD_FLAGS | __pa(pmd))); } - return pmd_p; + if (pud_large(*pud)) + return NULL; + + return pud; } static void __init sme_populate_pgd_large(struct sme_populate_pgd_data *ppd) { - pmd_t *pmd_p; + pud_t *pud; + pmd_t *pmd; - pmd_p = sme_prepare_pgd(ppd); - if (!pmd_p) + pud = sme_prepare_pgd(ppd); + if (!pud) return; - 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->paddr | ppd->pmd_flags)); + pmd = pmd_offset(pud, ppd->vaddr); + if (pmd_large(*pmd)) + return; + + set_pmd(pmd, __pmd(ppd->paddr | ppd->pmd_flags)); } static void __init sme_populate_pgd(struct sme_populate_pgd_data *ppd) { - pmd_t *pmd_p; - pte_t *pte_p; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; - pmd_p = sme_prepare_pgd(ppd); - if (!pmd_p) + pud = sme_prepare_pgd(ppd); + if (!pud) return; - pmd_p += pmd_index(ppd->vaddr); - if (native_pmd_val(*pmd_p)) { - if (native_pmd_val(*pmd_p) & _PAGE_PSE) - return; - - pte_p = (pte_t *)(native_pmd_val(*pmd_p) & ~PTE_FLAGS_MASK); - } else { - pmd_t pmd; - - pte_p = ppd->pgtable_area; - memset(pte_p, 0, sizeof(*pte_p) * PTRS_PER_PTE); - ppd->pgtable_area += sizeof(*pte_p) * PTRS_PER_PTE; - - pmd = native_make_pmd((pteval_t)pte_p + PMD_FLAGS); - native_set_pmd(pmd_p, pmd); + pmd = pmd_offset(pud, ppd->vaddr); + if (pmd_none(*pmd)) { + pte = ppd->pgtable_area; + memset(pte, 0, sizeof(pte) * PTRS_PER_PTE); + ppd->pgtable_area += sizeof(pte) * PTRS_PER_PTE; + set_pmd(pmd, __pmd(PMD_FLAGS | __pa(pte))); } - pte_p += pte_index(ppd->vaddr); - if (!native_pte_val(*pte_p)) - native_set_pte(pte_p, native_make_pte(ppd->paddr | ppd->pte_flags)); + if (pmd_large(*pmd)) + return; + + pte = pte_offset_map(pmd, ppd->vaddr); + if (pte_none(*pte)) + set_pte(pte, __pte(ppd->paddr | ppd->pte_flags)); } static void __init __sme_map_range_pmd(struct sme_populate_pgd_data *ppd) -- 2.30.2