From d5118d0fc4599f69116ec8de59052606e36e6306 Mon Sep 17 00:00:00 2001
From: John Baldwin <jhb@FreeBSD.org>
Date: Fri, 18 Nov 2022 10:04:23 -0800
Subject: [PATCH] vmm stat: Add a special nelems constant for arrays sized by
 vCPU count.

Reviewed by:	corvink, markj
Differential Revision:	https://reviews.freebsd.org/D37170
---
 sys/amd64/vmm/io/vlapic.c | 2 +-
 sys/amd64/vmm/vmm_stat.c  | 3 +++
 sys/amd64/vmm/vmm_stat.h  | 2 ++
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/sys/amd64/vmm/io/vlapic.c b/sys/amd64/vmm/io/vlapic.c
index bcfe6b498721..9c61726e77d7 100644
--- a/sys/amd64/vmm/io/vlapic.c
+++ b/sys/amd64/vmm/io/vlapic.c
@@ -905,7 +905,7 @@ vlapic_calcdest(struct vm *vm, cpuset_t *dmask, uint32_t dest, bool phys,
 	}
 }
 
-static VMM_STAT_ARRAY(IPIS_SENT, VM_MAXCPU, "ipis sent to vcpu");
+static VMM_STAT_ARRAY(IPIS_SENT, VMM_STAT_NELEMS_VCPU, "ipis sent to vcpu");
 
 static void
 vlapic_set_tpr(struct vlapic *vlapic, uint8_t val)
diff --git a/sys/amd64/vmm/vmm_stat.c b/sys/amd64/vmm/vmm_stat.c
index 2df4423bc60f..168a380b221b 100644
--- a/sys/amd64/vmm/vmm_stat.c
+++ b/sys/amd64/vmm/vmm_stat.c
@@ -70,6 +70,9 @@ vmm_stat_register(void *arg)
 	if (vst->scope == VMM_STAT_SCOPE_AMD && !vmm_is_svm())
 		return;
 
+	if (vst->nelems == VMM_STAT_NELEMS_VCPU)
+		vst->nelems = VM_MAXCPU;
+
 	if (vst_num_elems + vst->nelems >= MAX_VMM_STAT_ELEMS) {
 		printf("Cannot accommodate vmm stat type \"%s\"!\n", vst->desc);
 		return;
diff --git a/sys/amd64/vmm/vmm_stat.h b/sys/amd64/vmm/vmm_stat.h
index e40a960ec82a..050d3c13dda1 100644
--- a/sys/amd64/vmm/vmm_stat.h
+++ b/sys/amd64/vmm/vmm_stat.h
@@ -58,6 +58,8 @@ struct vmm_stat_type {
 
 void	vmm_stat_register(void *arg);
 
+#define	VMM_STAT_NELEMS_VCPU	(-1)
+
 #define	VMM_STAT_FDEFINE(type, nelems, desc, func, scope)		\
 	struct vmm_stat_type type[1] = {				\
 		{ -1, nelems, desc, func, scope }			\