From e6b28ec65b6d433624a2c290073bc356c4fce914 Mon Sep 17 00:00:00 2001
From: Dmitry Safonov <dima@arista.com>
Date: Tue, 12 Nov 2019 01:27:14 +0000
Subject: [PATCH 25/34] x86/vdso: On timens page fault prefault also VVAR page
Git-commit: e6b28ec65b6d433624a2c290073bc356c4fce914
Patch-mainline: v5.6-rc1
References: bsc#1164648,jsc#SLE-11493
As timens page has offsets to data on VVAR page VVAR is going
to be accessed shortly. Set it up with timens in one page fault
as optimization.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Co-developed-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20191112012724.250792-26-dima@arista.com
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
---
arch/x86/entry/vdso/vma.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index e5f336112cb1..d2fd8a57af7d 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -170,8 +170,23 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
* offset.
* See also the comment near timens_setup_vdso_data().
*/
- if (timens_page)
+ if (timens_page) {
+ unsigned long addr;
+ vm_fault_t err;
+
+ /*
+ * Optimization: inside time namespace pre-fault
+ * VVAR page too. As on timens page there are only
+ * offsets for clocks on VVAR, it'll be faulted
+ * shortly by VDSO code.
+ */
+ addr = vmf->address + (image->sym_timens_page - sym_offset);
+ err = vmf_insert_pfn(vma, addr, pfn);
+ if (unlikely(err & VM_FAULT_ERROR))
+ return err;
+
pfn = page_to_pfn(timens_page);
+ }
return vmf_insert_pfn(vma, vmf->address, pfn);
} else if (sym_offset == image->sym_pvclock_page) {
--
2.16.4