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([2600:1700:cb40:570f:4148:c992:66fd:90ee]) by smtp.gmail.com with ESMTPSA id s9-v6sm3877880pgc.16.2018.08.28.19.04.04 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 28 Aug 2018 19:04:05 -0700 (PDT) Subject: Re: [PATCH] x86/speculation/l1tf: fix off-by-one error when warning that system has too much RAM To: Andre Tomt , Andi Kleen , Vlastimil Babka Cc: Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , x86@kernel.org, linux-kernel@vger.kernel.org, Linus Torvalds , Dave Hansen , Michal Hocko , stable@vger.kernel.org, George Anchev References: <20180823134418.17008-1-vbabka@suse.cz> <20180823154437.GC12066@tassilo.jf.intel.com> <0fa72221-2272-4489-d9d3-0f68cb874087@tomt.net> From: Christopher Snowhill Message-ID: <73314d45-85bc-2a7d-a839-9c9ab4260592@gmail.com> Date: Tue, 28 Aug 2018 19:04:03 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <0fa72221-2272-4489-d9d3-0f68cb874087@tomt.net> Content-Type: multipart/mixed; boundary="------------CC8BAF4C829EACC00A65DCF6" Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------CC8BAF4C829EACC00A65DCF6 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 08/23/2018 07:22 PM, Andre Tomt wrote: > On 23. aug. 2018 17:44, Andi Kleen wrote: >> On Thu, Aug 23, 2018 at 03:44:18PM +0200, Vlastimil Babka wrote: >>> Two users have reported [1] that they have an "extremely unlikely" >>> system >>> with more than MAX_PA/2 memory and L1TF mitigation is not effective. >>> In fact >>> it's a CPU with 36bits phys limit (64GB) and 32GB memory, but due to >>> holes >>> in the e820 map, the main region is almost 500MB over the 32GB limit:= >> >> Ah I see it's a client part with very large DIMMs and someone being >> very brave and using that much memory without ECC. > > FYI; It is also happening on Xeon E3v2 (Ivy Bridge generation) w/ 32GB > of ECC RAM here, a low-end server part that officially supports up to > 32GB. > Indeed, I must be "very brave" to not have chucked this CPU and motherboard and RAM in the bin, and bought a new board, Xeon CPU, and ECC RAM. Maybe I'll consider that in the future, when I again have $1000+ to buy new kit. Which will probably be never, at this rate. >> [=C2=A0=C2=A0=C2=A0 0.000000] microcode: microcode updated early to re= vision 0x20, >> date =3D 2018-04-10 >> [=C2=A0=C2=A0=C2=A0 0.029728] L1TF: System has more than MAX_PA/2 memo= ry. L1TF >> mitigation not effective. >> [=C2=A0=C2=A0=C2=A0 1.063155] microcode: sig=3D0x306a9, pf=3D0x2, revi= sion=3D0x20 > > >> processor=C2=A0=C2=A0=C2=A0 : 7 >> vendor_id=C2=A0=C2=A0=C2=A0 : GenuineIntel >> cpu family=C2=A0=C2=A0=C2=A0 : 6 >> model=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 : 58 >> model name=C2=A0=C2=A0=C2=A0 : Intel(R) Xeon(R) CPU E3-1230 V2 @ 3.30G= Hz >> stepping=C2=A0=C2=A0=C2=A0 : 9 >> microcode=C2=A0=C2=A0=C2=A0 : 0x20 >> cpu MHz=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 : 3500.044 >> cache size=C2=A0=C2=A0=C2=A0 : 8192 KB >> physical id=C2=A0=C2=A0=C2=A0 : 0 >> siblings=C2=A0=C2=A0=C2=A0 : 8 >> core id=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 : 3 >> cpu cores=C2=A0=C2=A0=C2=A0 : 4 >> apicid=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 : 7 >> initial apicid=C2=A0=C2=A0=C2=A0 : 7 >> fpu=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 : yes >> fpu_exception=C2=A0=C2=A0=C2=A0 : yes >> cpuid level=C2=A0=C2=A0=C2=A0 : 13 >> wp=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 : yes >> flags=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 : fpu vme de pse tsc m= sr pae mce cx8 apic sep mtrr pge >> mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe >> syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl >> xtopology nonstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 monitor >> ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic >> popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm >> cpuid_fault epb pti ssbd ibrs ibpb stibp tpr_shadow vnmi flexpriority >> ept vpid fsgsbase smep erms xsaveopt dtherm ida arat pln pts flush_l1d= >> bugs=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 : cpu_meltdown spectre_= v1 spectre_v2 spec_store_bypass l1tf >> bogomips=C2=A0=C2=A0=C2=A0 : 6602.15 >> clflush size=C2=A0=C2=A0=C2=A0 : 64 >> cache_alignment=C2=A0=C2=A0=C2=A0 : 64 >> address sizes=C2=A0=C2=A0=C2=A0 : 36 bits physical, 48 bits virtual >> power management: > > --------------CC8BAF4C829EACC00A65DCF6 Content-Type: application/pgp-keys; name="pEpkey.asc" Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="pEpkey.asc" -----BEGIN PGP PUBLIC KEY BLOCK----- mQGNBFt8iZgBDADTkDHMQHF0QUsmTTT4t9OJEyLkNQlHg8ATzA4513rC6mxi88S2 QsSvj6/amIMAlqxopxqRMJPhTYn2OLH0OXHr6+pBtGd0r97XdDwj2u2CLiVCO/ii +pHutBJQBs1trupWTICSBABa08FEaSVeT4PadGzIl+lglMexD6CQ+aDDhComzB5G gtWyXpod32+iezYGIMaSvoMGJZlYqntaU9eiK0RzYSNrFGjeOAvelApXMyeFZvdL EVZqTNpYoz7wPIP3sqr6NUjG3EIhMKXMTDZIhJihov1Dv8BJ0HQx/dlCJGoc8gQI PMmIR/SHS6uw4nU5xZT+GODpRsu+EI58kHy350v6VeMiehoQvBPvv8VZaOQSSMWa XwCoU9RbEqXBVajsmtVYNRWQKzwL4Xl0djUI+cEqh6UnpoucwsZdK2i6KtJIs2Eh EN7JFDnhT5M7NUE4v4/Mu6oI5ZbMutNUmHVOniwBUiEFEjcl6XGFlK/1tOu+3cTC PSJH0j7tuiGV8/0AEQEAAbQnQ2hyaXN0b3BoZXIgU25vd2hpbGwgPGtvZGU1NEBn bWFpbC5jb20+iQHUBBMBCAA+FiEEuqGPVbnSUuU/5IZyKdu3XrDV77UFAlt8iZoC GwMFCQHhM4AFCwkIBwIGFQoJCAsCBBYCAwECHgECF4AACgkQKdu3XrDV77WDagwA p3xyd+KEzP8RgWkbz1axfSy8kOQbyPyhJz0aN1S94G4e4QSzEdjjvN3kWZcaSbj3 D14JL+Z1Tuf4lbtqG6CVHozHq3lMu9VCvP+fBrTpC++uzohG/I6X3NyimHfym1jt xknGTCyliVIBVjN+7Yvv/Lsz2fQ2gKoavJroaUdDWqD7XFnEdXiVzVM3UVp5FDyp 5HvjDG+c+chIldvPoXpRVKZ0igmQ4W8PQyeUc11YbAz32rblwRUXVpT+Uc2M0ZKe 6v870RC9aqJxi3SN+/ulVaefZ/J0UtL1uBBVr8aIBQt0jmKUEunZ2duVE4lODEbo wVacF9MtR99KDu5xVtPKXnldotM/lkusJ1QpIYQcGYBrR2YZckxrAsowN+5Ie4Ha PyH7iSywkcXmmX7QLEUUiBZ+KdkigrbDhJPkiJCbQo/oLd5N+J6UBdqpVKwnco9M SusIl3JpHEndb6pfcb5L3zDJ9VvQHfKTQ+pZFJJ5oIjwGd7PZfPKfHluI67waX7I uQGNBFt8iZkBDAC0B+cAkBS67uKTK0khrpiVu4ultlhoD+PwIWxPksddFGnw3y5M nZM9Y8WL3aKypxPhpbkDw98uDx4zhDTV4Xt5T1YT5Nn4lOF6jJeE9tS2u1g3vvWp S814EdyQYNPDzVmYLcSEsEnzaGDT/pUxGETwa+sIKpiQ0LNIjNnlgN1B4MqUVNye jDXADGg1SXt/sedR2U581Jf/M1VJOImORtyIMzVpgwLoTNFNv/yAhXiSaFmQ5HNl 6bRymRenA5faaG+cKAUtSLIrO6QFWDL+BuBKibEyTN75/BGr3SETAMINwAa5O6uh l1S2MCZhr4s/upe8Ng1tTs9Z9NIKU+Ox9EJK0UdbMSrp38PJHCDdyiIDVVzJ2CoP uoeS7a/o1q2ByxURCDEnIqI11MJi+AkjTWgiKtD5UseskzKJIJRq7Jnexr+cEvZh nvxN12uNzWdFoGuspTrFhwSj6tdZV2quQ7zmGVm9omcftm1RsGGqW5TfG+b3gehU fY67IgWOXlbsuH0AEQEAAYkBvAQYAQgAJhYhBLqhj1W50lLlP+SGcinbt16w1e+1 BQJbfImZAhsMBQkB4TOAAAoJECnbt16w1e+11LYL/ihSJ7Uor7TKvYO9Xc2HscIC 3PM+XMlna0v9rEY7xptMS60qAeXjLw4H0qCimHfaVmh5O6W9sIAe9e+78g+SaLj9 B1KRZ0motW8lku8ynKjKmovmfVnoGXQNgD3lUWLr7/qKtBDVqVoEHCAWG5wpLGPz xLkTQv8oE6Wd6q6SoqO+BhQoXDzA7bk/1K4m2ITFFwMiWSeHUnO4UEQwAq3vcgT8 LkEIWWVvDXHXOavpJqz+0s0BTr6fy/gEfdFic+FCTsX/qCsG/qHo8rlzadnWcR4Y 9QY/fppjZ4kM6cPmD81y4dkK08XI0p/xKfc4Gduyktk97qZWvqYOoG1qbFtmwlSA 5h+12KsgxeiYzkwRYjecTxz4v0+/C8R890EYNyj+ChY8qIUfG8f6x8bJknyjwC3q cPixFssI6GAJ4xYoSJ/fpNs91mX/O/OApr4vAn3NGOBbS0ZpWEGSUHdl7XtlGPN2 baT4mKdRKcknEBy5yy1AHFvk2/7/uHdYoslpOH4MBA=3D=3D =3DCUg/ -----END PGP PUBLIC KEY BLOCK----- --------------CC8BAF4C829EACC00A65DCF6--