Date: Wed, 22 Aug 2012 05:36:10 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-9@freebsd.org Subject: svn commit: r239560 - stable/9/sys/amd64/amd64 Message-ID: <201208220536.q7M5aAQM073963@svn.freebsd.org>
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Author: kib Date: Wed Aug 22 05:36:10 2012 New Revision: 239560 URL: http://svn.freebsd.org/changeset/base/239560 Log: MFC r239125: Do not apply errata 721 workaround when under hypervisor, since typical hypervisor does not implement access to the required MSR, causing #GP on boot. Modified: stable/9/sys/amd64/amd64/initcpu.c Directory Properties: stable/9/sys/ (props changed) Modified: stable/9/sys/amd64/amd64/initcpu.c ============================================================================== --- stable/9/sys/amd64/amd64/initcpu.c Wed Aug 22 05:30:51 2012 (r239559) +++ stable/9/sys/amd64/amd64/initcpu.c Wed Aug 22 05:36:10 2012 (r239560) @@ -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; } }
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