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Message-Id: <20200505134341.471542318@linutronix.de>
Date: Tue, 05 May 2020 15:41:26 +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 14/18] x86/kvm/vmx: Add hardirq tracing to guest enter/exit
Add hardirq tracing to guest enter/exit functions in the same way as it
is done in the user mode enter/exit code.
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Sean Christopherson <sean.j.christopherson@...el.com>
---
arch/x86/kvm/vmx/vmx.c | 25 +++++++++++++++++++++++--
1 file changed, 23 insertions(+), 2 deletions(-)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6604,9 +6604,19 @@ static void vmx_vcpu_run(struct kvm_vcpu
x86_spec_ctrl_set_guest(vmx->spec_ctrl, 0);
/*
- * Tell context tracking that this CPU is about to enter guest mode.
+ * VMENTER enables interrupts (host state), but the kernel state is
+ * interrupts disabled when this is invoked. Also tell RCU about
+ * it. This is the same logic as for exit_to_user_mode().
+ *
+ * 1) Trace interrupts on state
+ * 2) Prepare lockdep with RCU on
+ * 3) Invoke context tracking if enabled to adjust RCU state
+ * 4) Tell lockdep that interrupts are enabled
*/
+ trace_hardirqs_on_prepare();
+ lockdep_hardirqs_on_prepare(CALLER_ADDR0);
guest_enter_irqoff();
+ lockdep_hardirqs_on(CALLER_ADDR0);
/* L1D Flush includes CPU buffer clear to mitigate MDS */
if (static_branch_unlikely(&vmx_l1d_should_flush))
@@ -6623,9 +6633,20 @@ static void vmx_vcpu_run(struct kvm_vcpu
vcpu->arch.cr2 = read_cr2();
/*
- * Tell context tracking that this CPU is back.
+ * VMEXIT disables interrupts (host state), but tracing and lockdep
+ * have them in state 'on'. Same as enter_from_user_mode().
+ *
+ * 1) Tell lockdep that interrupts are disabled
+ * 2) Invoke context tracking if enabled to reactivate RCU
+ * 3) Trace interrupts off state
+ *
+ * This needs to be done before the below as native_read_msr()
+ * contains a tracepoint and x86_spec_ctrl_restore_host() calls
+ * into world and some more.
*/
+ lockdep_hardirqs_off(CALLER_ADDR0);
guest_exit_irqoff();
+ trace_hardirqs_off_prepare();
/*
* We do not use IBRS in the kernel. If this vCPU has used the
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