From: Bin Yang <bin.yang@intel.com>
To: tglx@linutronix.de, mingo@kernel.org, hpa@zytor.com,
x86@kernel.org, linux-kernel@vger.kernel.org,
peterz@infradead.org, dave.hansen@intel.com,
mark.gross@intel.com, bin.yang@intel.com
Subject: [PATCH v3 3/5] x86/mm: add help function to check specific protection flags in range
Date: Tue, 21 Aug 2018 01:16:24 +0000 [thread overview]
Message-ID: <1534814186-37067-4-git-send-email-bin.yang@intel.com> (raw)
In-Reply-To: <1534814186-37067-1-git-send-email-bin.yang@intel.com>
Introduce the needs_static_protections() helper to check specific
protection flags in range. It calls static_protection() to check
whether any part of the address/len range is forced to change from 'prot'.
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Bin Yang <bin.yang@intel.com>
---
arch/x86/mm/pageattr.c | 36 +++++++++++++++++++++++++++---------
1 file changed, 27 insertions(+), 9 deletions(-)
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 091f1d3..f630eb4 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -367,6 +367,30 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
}
/*
+ * static_protections() "forces" page protections for some address
+ * ranges. Return true if any part of the address/len range is forced
+ * to change from 'prot'.
+ */
+static inline bool
+needs_static_protections(pgprot_t prot, unsigned long address,
+ unsigned long len, unsigned long pfn)
+{
+ int i;
+
+ address &= PAGE_MASK;
+ len = PFN_ALIGN(len);
+ for (i = 0; i < (len >> PAGE_SHIFT); i++, address += PAGE_SIZE, pfn++) {
+ pgprot_t chk_prot = static_protections(prot, address, pfn);
+
+ if (pgprot_val(chk_prot) != pgprot_val(prot))
+ return true;
+ }
+
+ /* Does static_protections() demand a change ? */
+ return false;
+}
+
+/*
* Lookup the page table entry for a virtual address in a specific pgd.
* Return a pointer to the entry and the level of the mapping.
*/
@@ -556,7 +580,7 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
unsigned long nextpage_addr, numpages, pmask, psize, addr, pfn, old_pfn;
pte_t new_pte, old_pte, *tmp;
pgprot_t old_prot, new_prot, req_prot;
- int i, do_split = 1;
+ int do_split = 1;
enum pg_level level;
if (cpa->force_split)
@@ -660,14 +684,8 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
* static_protection() requires a different pgprot for one of
* the pages in the range we try to preserve:
*/
- pfn = old_pfn;
- for (i = 0; i < (psize >> PAGE_SHIFT); i++, addr += PAGE_SIZE, pfn++) {
- pgprot_t chk_prot = static_protections(req_prot, addr, pfn);
-
- if (pgprot_val(chk_prot) != pgprot_val(new_prot))
- goto out_unlock;
- }
-
+ if (needs_static_protections(new_prot, addr, psize, old_pfn))
+ goto out_unlock;
/* All checks passed. Just change the large mapping entry */
new_pte = pfn_pte(old_pfn, new_prot);
--
2.7.4
next prev parent reply other threads:[~2018-08-21 1:16 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-21 1:16 [PATCH v3 0/5] x86/mm: fix cpu stuck issue in __change_page_attr_set_clr Bin Yang
2018-08-21 1:16 ` [PATCH v3 1/5] x86/mm: avoid redundant checking if pgprot has no change Bin Yang
2018-09-03 21:57 ` Thomas Gleixner
2018-09-04 7:01 ` Yang, Bin
2018-09-04 7:49 ` Thomas Gleixner
2018-09-04 9:12 ` Yang, Bin
2018-09-04 9:22 ` Yang, Bin
2018-08-21 1:16 ` [PATCH v3 2/5] x86/mm: avoid static_protection() checking if not whole large page attr change Bin Yang
2018-08-21 1:16 ` Bin Yang [this message]
2018-09-03 22:10 ` [PATCH v3 3/5] x86/mm: add help function to check specific protection flags in range Thomas Gleixner
2018-09-04 6:22 ` Yang, Bin
2018-08-21 1:16 ` [PATCH v3 4/5] x86/mm: optimize static_protection() by using overlap() Bin Yang
2018-09-04 12:22 ` Thomas Gleixner
2018-09-07 1:14 ` Yang, Bin
2018-09-07 7:49 ` Thomas Gleixner
2018-09-07 8:04 ` Yang, Bin
2018-09-07 8:21 ` Thomas Gleixner
2018-09-07 8:26 ` Yang, Bin
2018-08-21 1:16 ` [PATCH v3 5/5] x86/mm: add WARN_ON_ONCE() for wrong large page mapping Bin Yang
2018-09-03 22:27 ` Thomas Gleixner
2018-09-04 6:32 ` Yang, Bin
2018-09-04 7:41 ` Thomas Gleixner
2018-09-04 16:52 ` Thomas Gleixner
2018-09-07 2:12 ` Yang, Bin
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