Let the fastpath code decide which exits can/can't be handled in the
fastpath when L2 is active, e.g. when KVM generates a VMX preemption
timer exit to forcefully regain control, there is no "work" to be done and
so such exits can be handled in the fastpath regardless of whether L1 or
L2 is active.
Moving the is_guest_mode() check into the fastpath code also makes it
easier to see that L2 isn't allowed to use the fastpath in most cases,
e.g. it's not immediately obvious why handle_fastpath_preemption_timer()
is called from the fastpath and the normal path.
Link: https://lore.kernel.org/r/20240110012705.506918-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
static fastpath_t svm_exit_handlers_fastpath(struct kvm_vcpu *vcpu)
{
static fastpath_t svm_exit_handlers_fastpath(struct kvm_vcpu *vcpu)
{
+ if (is_guest_mode(vcpu))
+ return EXIT_FASTPATH_NONE;
+
if (to_svm(vcpu)->vmcb->control.exit_code == SVM_EXIT_MSR &&
to_svm(vcpu)->vmcb->control.exit_info_1)
return handle_fastpath_set_msr_irqoff(vcpu);
if (to_svm(vcpu)->vmcb->control.exit_code == SVM_EXIT_MSR &&
to_svm(vcpu)->vmcb->control.exit_info_1)
return handle_fastpath_set_msr_irqoff(vcpu);
svm_complete_interrupts(vcpu);
svm_complete_interrupts(vcpu);
- if (is_guest_mode(vcpu))
- return EXIT_FASTPATH_NONE;
-
return svm_exit_handlers_fastpath(vcpu);
}
return svm_exit_handlers_fastpath(vcpu);
}
static fastpath_t vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu)
{
static fastpath_t vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu)
{
+ if (is_guest_mode(vcpu))
+ return EXIT_FASTPATH_NONE;
+
switch (to_vmx(vcpu)->exit_reason.basic) {
case EXIT_REASON_MSR_WRITE:
return handle_fastpath_set_msr_irqoff(vcpu);
switch (to_vmx(vcpu)->exit_reason.basic) {
case EXIT_REASON_MSR_WRITE:
return handle_fastpath_set_msr_irqoff(vcpu);
vmx_recover_nmi_blocking(vmx);
vmx_complete_interrupts(vmx);
vmx_recover_nmi_blocking(vmx);
vmx_complete_interrupts(vmx);
- if (is_guest_mode(vcpu))
- return EXIT_FASTPATH_NONE;
-
return vmx_exit_handlers_fastpath(vcpu);
}
return vmx_exit_handlers_fastpath(vcpu);
}