Fold the per-MSR WRMSR fastpath helpers into the main handler now that the
IPI path in particular is relatively tiny. In addition to eliminating a
decent amount of boilerplate, this removes the ugly -errno/1/0 => bool
conversion (which is "necessitated" by kvm_x2apic_icr_write_fast()).
Opportunistically drop the comment about IPIs, as the purpose of the
fastpath is hopefully self-evident, and _if_ it needs more documentation,
the documentation (and rules!) should be placed in a more central location.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/x86.c | 34 +++++-----------------------------
1 file changed, 5 insertions(+), 29 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e6c221f9b92e..a4441f036929 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2133,48 +2133,24 @@ static inline bool kvm_vcpu_exit_request(struct kvm_vcpu *vcpu)
kvm_request_pending(vcpu) || xfer_to_guest_mode_work_pending();
}
-/*
- * The fast path for frequent and performance sensitive wrmsr emulation,
- * i.e. the sending of IPI, sending IPI early in the VM-Exit flow reduces
- * the latency of virtual IPI by avoiding the expensive bits of transitioning
- * from guest to host, e.g. reacquiring KVM's SRCU lock. In contrast to the
- * other cases which must be called after interrupts are enabled on the host.
- */
-static int handle_fastpath_set_x2apic_icr_irqoff(struct kvm_vcpu *vcpu, u64 data)
-{
- if (!lapic_in_kernel(vcpu) || !apic_x2apic_mode(vcpu->arch.apic))
- return 1;
-
- return kvm_x2apic_icr_write_fast(vcpu->arch.apic, data);
-}
-
-static int handle_fastpath_set_tscdeadline(struct kvm_vcpu *vcpu, u64 data)
-{
- kvm_set_lapic_tscdeadline_msr(vcpu, data);
- return 0;
-}
-
fastpath_t handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vcpu)
{
u64 data = kvm_read_edx_eax(vcpu);
u32 msr = kvm_rcx_read(vcpu);
- bool handled;
int r;
switch (msr) {
case APIC_BASE_MSR + (APIC_ICR >> 4):
- handled = !handle_fastpath_set_x2apic_icr_irqoff(vcpu, data);
+ if (!lapic_in_kernel(vcpu) || !apic_x2apic_mode(vcpu->arch.apic) ||
+ kvm_x2apic_icr_write_fast(vcpu->arch.apic, data))
+ return EXIT_FASTPATH_NONE;
break;
case MSR_IA32_TSC_DEADLINE:
- handled = !handle_fastpath_set_tscdeadline(vcpu, data);
+ kvm_set_lapic_tscdeadline_msr(vcpu, data);
break;
default:
- handled = false;
- break;
- }
-
- if (!handled)
return EXIT_FASTPATH_NONE;
+ }
kvm_vcpu_srcu_read_lock(vcpu);
r = kvm_skip_emulated_instruction(vcpu);
--
2.50.1.565.gc32cd1483b-goog
