lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Thu, 11 Jun 2015 16:07:12 +0200
From:	Ingo Molnar <mingo@...nel.org>
To:	linux-kernel@...r.kernel.org
Cc:	linux-mml@...r.kernel.org, Andy Lutomirski <luto@...capital.net>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Denys Vlasenko <dvlasenk@...hat.com>,
	Brian Gerst <brgerst@...il.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Borislav Petkov <bp@...en8.de>,
	"H. Peter Anvin" <hpa@...or.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Oleg Nesterov <oleg@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Waiman Long <Waiman.Long@...com>
Subject: [PATCH 07/12] x86/virt/guest/xen: Remove use of pgd_list from the Xen guest code

xen_mm_pin_all()/unpin_all() are used to implement full guest instance
suspend/restore. It's a stop-all method that needs to iterate through
all allocated pgds in the system to fix them up for Xen's use.

This code uses pgd_list, probably because it was an easy interface.

But we want to remove the pgd_list, so convert the code over to walk
all tasks in the system. This is an equivalent method.

(As I don't use Xen this is was only build tested.)

Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Waiman Long <Waiman.Long@...com>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/xen/mmu.c | 34 ++++++++++++++++++++++++++++------
 1 file changed, 28 insertions(+), 6 deletions(-)

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index dd151b2045b0..87a8354435f8 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -853,18 +853,29 @@ static void xen_pgd_pin(struct mm_struct *mm)
  */
 void xen_mm_pin_all(void)
 {
-	struct page *page;
+	struct task_struct *g, *p;
 
+	rcu_read_lock();
 	spin_lock(&pgd_lock);
 
-	list_for_each_entry(page, &pgd_list, lru) {
+	for_each_process_thread(g, p) {
+		struct page *page;
+		pgd_t *pgd;
+
+		if (!p->mm)
+			continue;
+
+		pgd = p->mm->pgd;
+		page = virt_to_page(pgd);
+
 		if (!PagePinned(page)) {
-			__xen_pgd_pin(&init_mm, (pgd_t *)page_address(page));
+			__xen_pgd_pin(&init_mm, pgd);
 			SetPageSavePinned(page);
 		}
 	}
 
 	spin_unlock(&pgd_lock);
+	rcu_read_unlock();
 }
 
 /*
@@ -967,19 +978,30 @@ static void xen_pgd_unpin(struct mm_struct *mm)
  */
 void xen_mm_unpin_all(void)
 {
-	struct page *page;
+	struct task_struct *g, *p;
 
+	rcu_read_lock();
 	spin_lock(&pgd_lock);
 
-	list_for_each_entry(page, &pgd_list, lru) {
+	for_each_process_thread(g, p) {
+		struct page *page;
+		pgd_t *pgd;
+
+		if (!p->mm)
+			continue;
+
+		pgd = p->mm->pgd;
+		page = virt_to_page(pgd);
+
 		if (PageSavePinned(page)) {
 			BUG_ON(!PagePinned(page));
-			__xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page));
+			__xen_pgd_unpin(&init_mm, pgd);
 			ClearPageSavePinned(page);
 		}
 	}
 
 	spin_unlock(&pgd_lock);
+	rcu_read_unlock();
 }
 
 static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
-- 
2.1.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists