Date: Sat, 17 Mar 2012 13:10:23 -0400 From: Richard Yao <ryao@cs.stonybrook.edu> To: <freebsd-stable@FreeBSD.org> Subject: Re: AMD Erratum 383 crashes FreeBSD 9-Stable Message-ID: <4F64C57F.6040403@cs.stonybrook.edu> In-Reply-To: <4F64C50F.70409@cs.stonybrook.edu> References: <4F64C50F.70409@cs.stonybrook.edu>
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--------------enig011F0C707B4C007B5BD89A2C Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 03/17/12 13:08, Richard Yao wrote: > Dear FreeBSD Developers: >=20 > I used the ZFS Guru LiveCD to install FreeBSD 9 in KVM on a host system= > with an AMD Thuban processor (K10h). I then proceeded to compile perl > and the VM crashed. Linux's dmesg gave me the following hint as to the > cause: >=20 > [ 3568.234654] KVM: Guest triggered AMD Erratum 383 >=20 > I also tried installing Gentoo Prefix, a userland package manager like > NetBSD pkgsrc, and the VM also crashed with the same message when > compiling the first component. AMD has documented this issue, with a > workaround for hypervisors and a statement saying that they won't fix i= t: >=20 > "If system software performs uncommon methods to change the page size o= f > an active page table that is valid, the CPU core may, under a highly > specific and detailed set of conditions, form duplicate TLB entries for= > a single linear address. The CPU core will machine check if this page i= s > then accessed prior to it being invalidated from the TLB." >=20 > http://support.amd.com/us/Embedded_TechDocs/41322.pdf >=20 > Has anyone done anything to workaround this issue? I have a Gentoo > Hardened VM running on this machine which has no problem compiling > software, so I am sure that some sort of page table workaround is possi= ble. >=20 > Yours truly, > Richard Yao >=20 I was tired when I wrote that, so my eyes seem to have skipped some advice from AMD on how to workaround this in the kernel: "Affected software must ensure that page sizes are only increased or decreased after the entry is invalidated and flushed out of all TLBs. When flushing multiple entries from the TLB, software may wish to use a single MOV CR3 value to invalidate the TLB instead of repetitive INVLPG instructions" Also, I am not on the mailing list, so please CC replies to me. --------------enig011F0C707B4C007B5BD89A2C Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQIcBAEBAgAGBQJPZMV/AAoJELFAT5FmjZuEl8UP+wVYJ2jiXS7IBsVoCdtYyeHf vxeL5QOvEWHsrE9aVGLPttFxUeXm9t/HSrcr3/Vv2c+VfviFMSl1n3Qc6CMsh/XB uRvtLjGLFVkVFtppmo8EY8989dhEbrI3YG3Zc7348HvshUyH+77QohFdCWZob8Hp Kc+sk36oTAqShO+5tYw3alykGPjDJ4Se3IRm4dAVPAbMXbfYpvO5gjNCwiJ4ltxT L6tdk5HVXmeSPSIZt0lcIMrskNxpIUkqZKOIuNogUZsIpgYuXFSBrHAVKSUo946b 4BixFCRvnssWTtKKnv4+XwBe5DnJdlO33FIaHnXH1X2fXKvjRfQSYBZupONJ8yao aDzoD3RMfICWlHEirLBpMeVtLkRe2D9o0T9V7+/g98M3LuKr9cbzWcuQlrapYlcl Be3Pqs3WvFxmG179H8Y9sGx1riM2SrVVEBgyUgEz+bMJKoar04A1jMY85FlP7kBb +zMlX7XGhtOIHaiaNI+vJE0dIK6KL/oWCgfB10CzMjxJe0Hsxpi5ybHBzYLNi8l/ vHxj+E+VNe9+LFp091mlDLTFKctaghS466n84Vp68/lwYn3Ts09BZBSc8ol9Khov ZQ+Zfl1PXMfmMsuyxonTeXnN+gC31AqoHwZ2/LSI0LQxWboHMwUzk/tYt6nnNSYr hWF3Vo2T7U9CiVvM5h4m =3V2i -----END PGP SIGNATURE----- --------------enig011F0C707B4C007B5BD89A2C--
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