[PATCH 15/17] KVM: retpolines: x86: eliminate retpoline from vmx.c exit handlers

Andrea Arcangeli
2019-09-20T21:25:29Z

It's enough to check the exit value and issue a direct call to avoid
the retpoline for all the common vmexit reasons.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
---
arch/x86/kvm/vmx/vmx.c | 24 ++++++++++++++++++++++--
1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index a6e597025011..9aa73e216df2 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5866,9 +5866,29 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu)
}

if (exit_reason < kvm_vmx_max_exit_handlers
- && kvm_vmx_exit_handlers[exit_reason])
+ && kvm_vmx_exit_handlers[exit_reason]) {
+#ifdef CONFIG_RETPOLINE
+ if (exit_reason == EXIT_REASON_MSR_WRITE)
+ return handle_wrmsr(vcpu);
+ else if (exit_reason == EXIT_REASON_PREEMPTION_TIMER)
+ return handle_preemption_timer(vcpu);
+ else if (exit_reason == EXIT_REASON_PENDING_INTERRUPT)
+ return handle_interrupt_window(vcpu);
+ else if (exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT)
+ return handle_external_interrupt(vcpu);
+ else if (exit_reason == EXIT_REASON_HLT)
+ return handle_halt(vcpu);
+ else if (exit_reason == EXIT_REASON_PAUSE_INSTRUCTION)
+ return handle_pause(vcpu);
+ else if (exit_reason == EXIT_REASON_MSR_READ)
+ return handle_rdmsr(vcpu);
+ else if (exit_reason == EXIT_REASON_CPUID)
+ return handle_cpuid(vcpu);
+ else if (exit_reason == EXIT_REASON_EPT_MISCONFIG)
+ return handle_ept_misconfig(vcpu);
+#endif
return kvm_vmx_exit_handlers[exit_reason](vcpu);
- else {
+ } else {
vcpu_unimpl(vcpu, "vmx: unexpected exit reason 0x%x\n",
exit_reason);
dump_vmcs();