Author: jhb Date: Fri Mar 23 22:36:24 2018 New Revision: 331466 URL: https://svnweb.freebsd.org/changeset/base/331466
Log: Add a workaround to the hypervisor detection for older versions of KVM. Originally KVM set %eax to 0 in the cpuid leaf 0x4000000 rather than to the highest supported leaf in the hypervisor "branch". Detect this case and fixup the %eax value so that the hypervisor is still detected. Reported by: jpaetzel Reviewed by: kib MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D14810 Modified: head/sys/x86/x86/identcpu.c Modified: head/sys/x86/x86/identcpu.c ============================================================================== --- head/sys/x86/x86/identcpu.c Fri Mar 23 21:06:06 2018 (r331465) +++ head/sys/x86/x86/identcpu.c Fri Mar 23 22:36:24 2018 (r331466) @@ -1304,6 +1304,18 @@ identify_hypervisor(void) if (cpu_feature2 & CPUID2_HV) { vm_guest = VM_GUEST_VM; do_cpuid(0x40000000, regs); + + /* + * KVM from Linux kernels prior to commit + * 57c22e5f35aa4b9b2fe11f73f3e62bbf9ef36190 set %eax + * to 0 rather than a valid hv_high value. Check for + * the KVM signature bytes and fixup %eax to the + * highest supported leaf in that case. + */ + if (regs[0] == 0 && regs[1] == 0x4b4d564b && + regs[2] == 0x564b4d56 && regs[3] == 0x0000004d) + regs[0] = 0x40000001; + if (regs[0] >= 0x40000000) { hv_high = regs[0]; ((u_int *)&hv_vendor)[0] = regs[1]; _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
