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Date: Tue, 05 May 2020 15:41:27 +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 15/18] x86/kvm/svm: Handle hardirqs proper on 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/svm/svm.c | 30 +++++++++++++++++++++++++-----
1 file changed, 25 insertions(+), 5 deletions(-)
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3331,12 +3331,23 @@ static void svm_vcpu_run(struct kvm_vcpu
x86_spec_ctrl_set_guest(svm->spec_ctrl, svm->virt_spec_ctrl);
/*
- * Tell context tracking that this CPU is about to enter guest
- * mode. This has to be after x86_spec_ctrl_set_guest() because
- * that can take locks (lockdep needs RCU) and calls into world and
- * some more.
+ * 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
+ *
+ * This has to be after x86_spec_ctrl_set_guest() because that can
+ * take locks (lockdep needs RCU) and calls into world and some
+ * more.
*/
+ trace_hardirqs_on_prepare();
+ lockdep_hardirqs_on_prepare(CALLER_ADDR0);
guest_enter_irqoff();
+ lockdep_hardirqs_on(CALLER_ADDR0);
__svm_vcpu_run(svm->vmcb_pa, (unsigned long *)&svm->vcpu.arch.regs);
@@ -3348,14 +3359,23 @@ static void svm_vcpu_run(struct kvm_vcpu
loadsegment(gs, svm->host.gs);
#endif
#endif
+
/*
- * Tell context tracking that this CPU is back.
+ * VMEXIT disables interrupts (host state, see the CLI in the ASM
+ * above), 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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