[PATCH v3 9/10] x86/mm: Fix __split_large_page() to handle large PAT bit
From: Toshi Kani <hidden>
Date: 2015-08-05 21:45:30
Also in:
lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit), x86 mm · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Andy Lutomirski, Peter Zijlstra
__split_large_page() is called from __change_page_attr() to change the map attribute by splitting the large page into smaller pages. This function uses pte_pfn() and pte_pgprot() for PUD/PMD, which do not handle the large PAT bit properly. Fix __split_large_page() to use corresponding p?d_pfn() and p?d_pgprot(). Signed-off-by: Toshi Kani <redacted> Cc: Juergen Gross <jgross@suse.com> Cc: Thomas Gleixner <redacted> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Andrew Morton <akpm@linux-foundation.org> --- arch/x86/mm/pageattr.c | 31 +++++++++++++++++++------------ 1 file changed, 19 insertions(+), 12 deletions(-)
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 2724755..d0e40ed 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c@@ -606,7 +606,7 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address, struct page *base) { pte_t *pbase = (pte_t *)page_address(base); - unsigned long pfn, pfninc = 1; + unsigned long ref_pfn, pfn, pfninc = 1; unsigned int i, level; pte_t *tmp; pgprot_t ref_prot;
@@ -623,26 +623,33 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address, } paravirt_alloc_pte(&init_mm, page_to_pfn(base)); - ref_prot = pte_pgprot(pte_clrhuge(*kpte)); - /* promote PAT bit to correct position */ - if (level == PG_LEVEL_2M) + switch (level) { + case PG_LEVEL_2M: + ref_prot = pmd_pgprot(*(pmd_t *)kpte); + /* clear PSE and promote PAT bit to correct position */ ref_prot = pgprot_large_2_4k(ref_prot); + ref_pfn = pmd_pfn(*(pmd_t *)kpte); + break; -#ifdef CONFIG_X86_64 - if (level == PG_LEVEL_1G) { + case PG_LEVEL_1G: + ref_prot = pud_pgprot(*(pud_t *)kpte); + ref_pfn = pud_pfn(*(pud_t *)kpte); pfninc = PMD_PAGE_SIZE >> PAGE_SHIFT; + /* - * Set the PSE flags only if the PRESENT flag is set + * Clear the PSE flags if the PRESENT flag is not set * otherwise pmd_present/pmd_huge will return true * even on a non present pmd. */ - if (pgprot_val(ref_prot) & _PAGE_PRESENT) - pgprot_val(ref_prot) |= _PAGE_PSE; - else + if (!(pgprot_val(ref_prot) & _PAGE_PRESENT)) pgprot_val(ref_prot) &= ~_PAGE_PSE; + break; + + default: + spin_unlock(&pgd_lock); + return 1; } -#endif /* * Set the GLOBAL flags only if the PRESENT flag is set
@@ -658,7 +665,7 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address, /* * Get the target pfn from the original entry: */ - pfn = pte_pfn(*kpte); + pfn = ref_pfn; for (i = 0; i < PTRS_PER_PTE; i++, pfn += pfninc) set_pte(&pbase[i], pfn_pte(pfn, canon_pgprot(ref_prot))); --
To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>