From bfdf1ebc2056f733f1fc31600892287fae8e4d54 Mon Sep 17 00:00:00 2001 From: grehan Date: Sat, 25 Mar 2017 05:05:12 +0000 Subject: MFC r315361 and r315364: Hide MONITORX/MWAITX from guests. r315361 Add the AMD MONITORX/MWAITX feature definition introduced in Bulldozer/Ryzen CPUs. r315364 Hide the AMD MONITORX/MWAITX capability. Otherwise, recent Linux guests will use these instructions, resulting in #UD exceptions since bhyve doesn't implement MONITOR/MWAIT exits. This fixes boot-time hangs in recent Linux guests on Ryzen CPUs (and probably Bulldozer aka AMD FX as well). --- sys/amd64/vmm/x86.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'sys/amd64/vmm') diff --git a/sys/amd64/vmm/x86.c b/sys/amd64/vmm/x86.c index 525e1d9..61d99d5 100644 --- a/sys/amd64/vmm/x86.c +++ b/sys/amd64/vmm/x86.c @@ -176,6 +176,9 @@ x86_emulate_cpuid(struct vm *vm, int vcpu_id, /* Don't advertise the OS visible workaround feature */ regs[2] &= ~AMDID2_OSVW; + /* Hide mwaitx/monitorx capability from the guest */ + regs[2] &= ~AMDID2_MWAITX; + /* * Hide rdtscp/ia32_tsc_aux until we know how * to deal with them. -- cgit v1.1