linux-kernel - [patch V4 part 2 16/18] context_tracking: Make guest

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Date:   Tue, 05 May 2020 15:41:28 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, "Paul E. McKenney" <paulmck@...nel.org>,
        Andy Lutomirski <luto@...nel.org>,
        Alexandre Chartre <alexandre.chartre@...cle.com>,
        Frederic Weisbecker <frederic@...nel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Petr Mladek <pmladek@...e.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Joel Fernandes <joel@...lfernandes.org>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Juergen Gross <jgross@...e.com>,
        Brian Gerst <brgerst@...il.com>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Will Deacon <will@...nel.org>
Subject: [patch V4 part 2 16/18] context_tracking: Make guest_enter/exit()
 .noinstr ready

Force inlining of the helpers and mark the instrumentable parts
accordingly.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Paolo Bonzini <pbonzini@...hat.com>
---
 include/linux/context_tracking.h |   21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

--- a/include/linux/context_tracking.h
+++ b/include/linux/context_tracking.h
@@ -101,12 +101,14 @@ static inline void context_tracking_init
 
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
 /* must be called with irqs disabled */
-static inline void guest_enter_irqoff(void)
+static __always_inline void guest_enter_irqoff(void)
 {
+	instr_begin();
 	if (vtime_accounting_enabled_this_cpu())
 		vtime_guest_enter(current);
 	else
 		current->flags |= PF_VCPU;
+	instr_end();
 
 	if (context_tracking_enabled())
 		__context_tracking_enter(CONTEXT_GUEST);
@@ -118,39 +120,48 @@ static inline void guest_enter_irqoff(vo
 	 * one time slice). Lets treat guest mode as quiescent state, just like
 	 * we do with user-mode execution.
 	 */
-	if (!context_tracking_enabled_this_cpu())
+	if (!context_tracking_enabled_this_cpu()) {
+		instr_begin();
 		rcu_virt_note_context_switch(smp_processor_id());
+		instr_end();
+	}
 }
 
-static inline void guest_exit_irqoff(void)
+static __always_inline void guest_exit_irqoff(void)
 {
 	if (context_tracking_enabled())
 		__context_tracking_exit(CONTEXT_GUEST);
 
+	instr_begin();
 	if (vtime_accounting_enabled_this_cpu())
 		vtime_guest_exit(current);
 	else
 		current->flags &= ~PF_VCPU;
+	instr_end();
 }
 
 #else
-static inline void guest_enter_irqoff(void)
+static __always_inline void guest_enter_irqoff(void)
 {
 	/*
 	 * This is running in ioctl context so its safe
 	 * to assume that it's the stime pending cputime
 	 * to flush.
 	 */
+	instr_begin();
 	vtime_account_kernel(current);
 	current->flags |= PF_VCPU;
 	rcu_virt_note_context_switch(smp_processor_id());
+	instr_end();
 }
 
-static inline void guest_exit_irqoff(void)
+static __always_inline void guest_exit_irqoff(void)
 {
+	instr_begin();
 	/* Flush the guest cputime we spent on the guest */
 	vtime_account_kernel(current);
 	current->flags &= ~PF_VCPU;
+	instr_end();
 }
 #endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */