further speed up delivery of interrupts to a running vcpu.

this records which physical cpu a vcpu is running on. this is used
by the code that marks a vcpu as having a pending interrupt to check
if the vcpu is currently running. if it thinks the vcpu is running,
it sends a nop IPI to the physical cpu it is running on to trigger
a vmexit, which in turn runs interrupt handling in the guest.

ok mlarkin@

diff --git a/sys/arch/amd64/amd64/vmm.c b/sys/arch/amd64/amd64/vmm.c
index 2defbd0..5ef771b 100644 (file)
--- a/sys/arch/amd64/amd64/vmm.c
+++ b/sys/arch/amd64/amd64/vmm.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: vmm.c,v 1.327 2022/11/08 18:08:43 mlarkin Exp $       */
+/*     $OpenBSD: vmm.c,v 1.328 2022/11/08 19:18:47 dlg Exp $   */
 /*
  * Copyright (c) 2014 Mike Larkin <mlarkin@openbsd.org>
  *
@@ -878,6 +878,7 @@ vm_intr_pending(struct vm_intr_params *vip)
 {
        struct vm *vm;
        struct vcpu *vcpu;
+       struct cpu_info *ci;
        int error, ret = 0;
 
        /* Find the desired VM */
@@ -895,6 +896,9 @@ vm_intr_pending(struct vm_intr_params *vip)
        }
 
        vcpu->vc_intr = vip->vip_intr;
+       ci = READ_ONCE(vcpu->vc_curcpu);
+       if (ci != NULL)
+               x86_send_ipi(ci, X86_IPI_NOP);
 
        refcnt_rele_wake(&vcpu->vc_refcnt);
 out:
@@ -4559,6 +4563,7 @@ vm_run(struct vm_run_params *vrp)
                }
        }
 
+       WRITE_ONCE(vcpu->vc_curcpu, curcpu());
        /* Run the VCPU specified in vrp */
        if (vcpu->vc_virt_mode == VMM_MODE_VMX ||
            vcpu->vc_virt_mode == VMM_MODE_EPT) {
@@ -4567,6 +4572,7 @@ vm_run(struct vm_run_params *vrp)
                   vcpu->vc_virt_mode == VMM_MODE_RVI) {
                ret = vcpu_run_svm(vcpu, vrp);
        }
+       WRITE_ONCE(vcpu->vc_curcpu, NULL);
 
        atomic_dec_int(&vm->vm_vcpus_running);
        if (ret == 0 || ret == EAGAIN) {

diff --git a/sys/arch/amd64/include/vmmvar.h b/sys/arch/amd64/include/vmmvar.h
index 6a5296d..cbe9015 100644 (file)
--- a/sys/arch/amd64/include/vmmvar.h
+++ b/sys/arch/amd64/include/vmmvar.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: vmmvar.h,v 1.81 2022/09/01 22:01:40 dv Exp $  */
+/*     $OpenBSD: vmmvar.h,v 1.82 2022/11/08 19:18:47 dlg Exp $ */
 /*
  * Copyright (c) 2014 Mike Larkin <mlarkin@openbsd.org>
  *
@@ -934,6 +934,7 @@ struct vcpu {
        struct rwlock vc_lock;
        struct refcnt vc_refcnt;                /* [a] */
 
+       struct cpu_info *vc_curcpu;             /* [a] */
        struct cpu_info *vc_last_pcpu;          /* [v] */
        struct vm_exit vc_exit;                 /* [v] */