On 05/05/20 15:41, Thomas Gleixner wrote: > 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 <[email protected]> > Cc: Paolo Bonzini <[email protected]> > Cc: Sean Christopherson <[email protected]> > --- > 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 >
Acked-by: Paolo Bonzini <[email protected]>
