From 1187e5b624e0b9654c2c266a43ac9367aefe2577 Mon Sep 17 00:00:00 2001 From: kib Date: Tue, 7 Aug 2012 08:36:10 +0000 Subject: Do not apply errata 721 workaround when under hypervisor, since typical hypervisor does not implement access to the required MSR, causing #GP on boot. Reported and tested by: olgeni PR: amd64/170388 MFC after: 3 days --- sys/amd64/amd64/initcpu.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'sys/amd64') diff --git a/sys/amd64/amd64/initcpu.c b/sys/amd64/amd64/initcpu.c index 3890551..dbeaec6 100644 --- a/sys/amd64/amd64/initcpu.c +++ b/sys/amd64/amd64/initcpu.c @@ -91,11 +91,17 @@ init_amd(void) * * http://support.amd.com/us/Processor_TechDocs/41322_10h_Rev_Gd.pdf * http://support.amd.com/us/Processor_TechDocs/44739_12h_Rev_Gd.pdf + * + * Hypervisors do not provide access to the errata MSR, + * causing #GP exception on attempt to apply the errata. The + * MSR write shall be done on host and persist globally + * anyway, so do not try to do it when under virtualization. */ switch (CPUID_TO_FAMILY(cpu_id)) { case 0x10: case 0x12: - wrmsr(0xc0011029, rdmsr(0xc0011029) | 1); + if ((cpu_feature2 & CPUID2_HV) == 0) + wrmsr(0xc0011029, rdmsr(0xc0011029) | 1); break; } } -- cgit v1.1