git: 55096ebddc15 - stable/15 - arm64/vmm: Move the vgic_max_cpu_count() check

The branch stable/15 has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=55096ebddc1557b7f0e4cb294878fcc8621de37b

commit 55096ebddc1557b7f0e4cb294878fcc8621de37b
Author:     Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2025-11-04 16:58:25 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2025-11-18 14:57:42 +0000

    arm64/vmm: Move the vgic_max_cpu_count() check
    
    vm_alloc_vcpu() is called quite frequently, and we don't need to apply
    the vgic limit unless we're actually allocating a vcpu structure for the
    first time.
    
    No functional change intended.
    
    Reviewed by:    andrew
    MFC after:      2 weeks
    Sponsored by:   The FreeBSD Foundation
    Sponsored by:   Klara, Inc.
    Differential Revision:  https://reviews.freebsd.org/D53580
    
    (cherry picked from commit f3a7ed2047dffaebbfbb3920e993e9df424be728)
---
 sys/arm64/vmm/vmm.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/sys/arm64/vmm/vmm.c b/sys/arm64/vmm/vmm.c
index dfaba058e205..5225b995a75d 100644
--- a/sys/arm64/vmm/vmm.c
+++ b/sys/arm64/vmm/vmm.c
@@ -394,10 +394,6 @@ vm_alloc_vcpu(struct vm *vm, int vcpuid)
 	if (vcpuid < 0 || vcpuid >= vm_get_maxcpus(vm))
 		return (NULL);
 
-	/* Some interrupt controllers may have a CPU limit */
-	if (vcpuid >= vgic_max_cpu_count(vm->cookie))
-		return (NULL);
-
 	vcpu = (struct vcpu *)
 	    atomic_load_acq_ptr((uintptr_t *)&vm->vcpu[vcpuid]);
 	if (__predict_true(vcpu != NULL))
@@ -406,6 +402,12 @@ vm_alloc_vcpu(struct vm *vm, int vcpuid)
 	sx_xlock(&vm->vcpus_init_lock);
 	vcpu = vm->vcpu[vcpuid];
 	if (vcpu == NULL && !vm->dying) {
+		/* Some interrupt controllers may have a CPU limit */
+		if (vcpuid >= vgic_max_cpu_count(vm->cookie)) {
+			sx_xunlock(&vm->vcpus_init_lock);
+			return (NULL);
+		}
+
 		vcpu = vcpu_alloc(vm, vcpuid);
 		vcpu_init(vcpu);