vmm(4): remove locking in vmm_intr_pending

Removes a lock around an atomic write; this lock was causing slowdowns
since the lock being requested is nearly always unavailable because it
is held while the VM is running.

Noticed by claudio@, help from mpi@, dlg@ and claudio@.

ok dv

diff --git a/sys/arch/amd64/amd64/vmm.c b/sys/arch/amd64/amd64/vmm.c
index f6ad02e..2defbd0 100644 (file)
--- a/sys/arch/amd64/amd64/vmm.c
+++ b/sys/arch/amd64/amd64/vmm.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: vmm.c,v 1.326 2022/11/07 12:29:12 dv Exp $    */
+/*     $OpenBSD: vmm.c,v 1.327 2022/11/08 18:08:43 mlarkin Exp $       */
 /*
  * Copyright (c) 2014 Mike Larkin <mlarkin@openbsd.org>
  *
@@ -894,9 +894,7 @@ vm_intr_pending(struct vm_intr_params *vip)
                goto out;
        }
 
-       rw_enter_write(&vcpu->vc_lock);
        vcpu->vc_intr = vip->vip_intr;
-       rw_exit_write(&vcpu->vc_lock);
 
        refcnt_rele_wake(&vcpu->vc_refcnt);
 out:
@@ -3526,7 +3524,7 @@ vcpu_reset_regs_vmx(struct vcpu *vcpu, struct vcpu_reg_state *vrs)
        vmx_setmsrbrw(vcpu, MSR_FSBASE);
        vmx_setmsrbrw(vcpu, MSR_GSBASE);
        vmx_setmsrbrw(vcpu, MSR_KERNELGSBASE);
-       
+
        vmx_setmsrbr(vcpu, MSR_MISC_ENABLE);
        vmx_setmsrbr(vcpu, MSR_TSC);