On Thursday, February 06, 2014 6:00:01 am Simon Matter wrote: > The following reply was made to PR amd64/186061; it has been noted by GNATS. > > From: "Simon Matter" <simon.mat...@invoca.ch> > To: bug-follo...@freebsd.org > Cc: simon.mat...@invoca.ch > Subject: Re: amd64/186061: FreeBSD 10 crashes as KVM guest on GNU/Linux on > AMD family 10h CPUs > Date: Thu, 6 Feb 2014 11:46:41 +0100 > > ------=_20140206114641_95473 > Content-Type: text/plain; charset="iso-8859-1" > Content-Transfer-Encoding: 8bit > > Hi, > > After thinking about it again it seems the proposed solution may not be > enough. At least KVM allows to migrate guests from an Intel to an AMD > processor. That means in case of running as a vm guest, it's required to > always enable "AMD Erratum 383" workaround. Otherwise, after migration to > an affected AMD Family 10h processor, the guest could triggered AMD > Erratum 383. > > I've tried to implement this and attached patch fixes the problem for me. > Would me nice if someone with more experience than me could have a look at > it.
I suspect you do not need the mca.c change as I doubt any hypervisors are going to pass machine check handling on to guests. Presumably they will handle that in the host OS instead. > Thanks, > Simon > ------=_20140206114641_95473 > Content-Type: text/x-diff; name="vm-erratum383.patch" > Content-Transfer-Encoding: 8bit > Content-Disposition: attachment; filename="vm-erratum383.patch" > > --- /usr/src/sys/x86/x86/mca.c.orig 2014-01-16 21:35:03.000000000 +0100 > +++ /usr/src/sys/x86/x86/mca.c 2014-02-05 22:15:53.109619475 +0100 > @@ -720,8 +720,8 @@ > * parity (L1TP) errors is disabled, enable the recommended workaround > * for Erratum 383. > */ > - if (cpu_vendor_id == CPU_VENDOR_AMD && > - CPUID_TO_FAMILY(cpu_id) == 0x10 && amd10h_L1TP) > + if (vm_guest != VM_GUEST_NO || (cpu_vendor_id == CPU_VENDOR_AMD && > + CPUID_TO_FAMILY(cpu_id) == 0x10 && amd10h_L1TP)) > workaround_erratum383 = 1; > > mca_banks = mcg_cap & MCG_CAP_COUNT; > --- /usr/src/sys/i386/i386/pmap.c.orig 2014-01-16 21:33:36.000000000 +0100 > +++ /usr/src/sys/i386/i386/pmap.c 2014-02-05 22:25:28.395821316 +0100 > @@ -752,12 +752,12 @@ > pv_entry_high_water = 9 * (pv_entry_max / 10); > > /* > - * If the kernel is running in a virtual machine on an AMD Family 10h > - * processor, then it must assume that MCA is enabled by the virtual > - * machine monitor. > + * If the kernel is running in a virtual machine on any processor > + * family, then it must assume that MCA is enabled by the virtual > + * machine monitor and the vm may migrate to an AMD Family 10h > + * processor. > */ > - if (vm_guest == VM_GUEST_VM && cpu_vendor_id == CPU_VENDOR_AMD && > - CPUID_TO_FAMILY(cpu_id) == 0x10) > + if (vm_guest != VM_GUEST_NO) > workaround_erratum383 = 1; > > /* > --- /usr/src/sys/amd64/amd64/pmap.c.orig 2014-01-16 21:33:04.000000000 +0100 > +++ /usr/src/sys/amd64/amd64/pmap.c 2014-02-05 22:28:25.814349113 +0100 > @@ -1005,12 +1005,12 @@ > } > > /* > - * If the kernel is running in a virtual machine on an AMD Family 10h > - * processor, then it must assume that MCA is enabled by the virtual > - * machine monitor. > + * If the kernel is running in a virtual machine on any processor > + * family, then it must assume that MCA is enabled by the virtual > + * machine monitor and the vm may migrate to an AMD Family 10h > + * processor. > */ > - if (vm_guest == VM_GUEST_VM && cpu_vendor_id == CPU_VENDOR_AMD && > - CPUID_TO_FAMILY(cpu_id) == 0x10) > + if (vm_guest != VM_GUEST_NO) > workaround_erratum383 = 1; > > /* > ------=_20140206114641_95473-- > > > _______________________________________________ > freebsd-amd64@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-amd64 > To unsubscribe, send any mail to "freebsd-amd64-unsubscr...@freebsd.org" > -- John Baldwin _______________________________________________ freebsd-amd64@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-amd64 To unsubscribe, send any mail to "freebsd-amd64-unsubscr...@freebsd.org"
