From: dv <dv@openbsd.org>
Date: Wed, 4 Sep 2024 16:12:40 +0000 (+0000)
Subject: vmm: set highest cpuid feature leaf based on host cpu.
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=c8c95121f802c4f6a63edc7145ec493573589639;p=openbsd

vmm: set highest cpuid feature leaf based on host cpu.

Fixes Linux guests on older Intel hardware. vmm was reporting a
value that doesn't match the host. Cap it at the highest value vmm
currently emulates.

ok bluhm@, ratchov@
---

diff --git a/sys/arch/amd64/amd64/vmm_machdep.c b/sys/arch/amd64/amd64/vmm_machdep.c
index 0e8e2a52645..04944d513bf 100644
--- a/sys/arch/amd64/amd64/vmm_machdep.c
+++ b/sys/arch/amd64/amd64/vmm_machdep.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: vmm_machdep.c,v 1.35 2024/09/04 07:54:51 mglocker Exp $ */
+/* $OpenBSD: vmm_machdep.c,v 1.36 2024/09/04 16:12:40 dv Exp $ */
 /*
  * Copyright (c) 2014 Mike Larkin <mlarkin@openbsd.org>
  *
@@ -6282,7 +6282,8 @@ vmm_handle_cpuid(struct vcpu *vcpu)
 		*rdx = 0;
 		break;
 	case 0x80000000:	/* Extended function level */
-		*rax = 0x8000001f; /* curcpu()->ci_pnfeatset */
+		/* We don't emulate past 0x8000001f currently. */
+		*rax = min(curcpu()->ci_pnfeatset, 0x8000001f);
 		*rbx = 0;
 		*rcx = 0;
 		*rdx = 0;