Messages in this thread | | | Subject | Re: [PATCH] x86/mm: Rewrite sme_populate_pgd() in a more sensible way | From | Tom Lendacky <> | Date | Mon, 4 Dec 2017 08:19:11 -0600 |
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On 12/4/2017 5:23 AM, Kirill A. Shutemov wrote: > 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.
Hi Kirill,
Unfortunately, some of these can't be changed. The use of p4d_offset(), pud_offset(), etc., use non-identity mapped virtual addresses which cause failures at this point of the boot process. Also, calls such as __p4d(), __pud(), etc., are part of the paravirt support and can't be used yet, either. I can take a closer look at some of the others (p*d_none() and p*d_large()) which make use of the native_ macros, but my worry would be that these get changed in the future to the non-native calls and then boot failures occur.
Thanks, Tom
> > 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; > } >
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