Date: Sat, 12 May 2018 11:21:12 +0200 From: Frank Ebert <frank.ebert@freenet.de> To: freebsd-virtualization@freebsd.org Subject: Re: wrmsr to register 0x49(0x1) on vcpu x Message-ID: <20180512112112.567c698a@mimo> In-Reply-To: <d329dda8-dd74-1aaa-ccf3-b2b3f86fe146@edenist.net> References: <20180508071846.18435a99@mimo> <d329dda8-dd74-1aaa-ccf3-b2b3f86fe146@edenist.net>
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--Sig_/6thf5eBHeeKbdbxUgz+kI0Y Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hi Josh, thank you very much for your reply. I also assume that it has something to do with spectre, because the changelog says "Update AGESA 1.0.0.5=E2=80= =9C. AGESA seems to be microcode for AMD CPUs. But 1.0.0.5 appears to be too old (?) to include code for spectre, isn=E2=80=99t it? I have checked the CPU features. Attached you find my dmesg before and after the BIOS-Update: Full output before BIOS upgrade: CPU: AMD Ryzen Threadripper 1950X 16-Core Processor (3393.70-MHz K8-class CPU) Origin=3D"AuthenticAMD" Id=3D0x800f11 Family=3D0x17 Model=3D0x1 Stepping=3D1 Features=3D0x178bfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,= MCA,CMOV,PAT,PSE36,CLFLUSH,MMX,FXSR,SSE,SSE2,HTT> Features2=3D0x7ed8320b<SSE3,PCLMULQDQ,MON,SSSE3,FMA,CX16,SSE4.1,SSE4.2,MOVB= E,POPCNT,AESNI,XSAVE,OSXSAVE,AVX,F16C,RDRAND> AMD Features=3D0x2e500800<SYSCALL,NX,MMX+,FFXSR,Page1GB,RDTSCP,LM> AMD Features2=3D0x35c233ff<LAHF,CMP,SVM,ExtAPIC,CR8,ABM,SSE4A,MAS,Prefetch,OSVW= ,SKINIT,WDT,TCE,Topology,PCXC,PNXC,DBE,PL2I,MWAITX> Structured Extended Features=3D0x209c01a9<FSGSBASE,BMI1,AVX2,SMEP,BMI2,RDSEED,ADX,SMAP,CLFLUSHO= PT,SHA> XSAVE Features=3D0xf<XSAVEOPT,XSAVEC,XINUSE,XSAVES> SVM: NP,NRIP,VClean,AFlush,DAssist,NAsids=3D32768 TSC: P-state invariant, performance statistics Full output after BIOS upgrade: CPU: AMD Ryzen Threadripper 1950X 16-Core Processor (3393.72-MHz K8-class CPU) Origin=3D"AuthenticAMD" Id=3D0x800f11 Family=3D0x17 Model=3D0x1 Stepping=3D1 Features=3D0x178bfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,= MCA,CMOV,PAT,PSE36,CLFLUSH,MMX,FXSR,SSE,SSE2,HTT> Features2=3D0x7ed8320b<SSE3,PCLMULQDQ,MON,SSSE3,FMA,CX16,SSE4.1,SSE4.2,MOVB= E,POPCNT,AESNI,XSAVE,OSXSAVE,AVX,F16C,RDRAND> AMD Features=3D0x2e500800<SYSCALL,NX,MMX+,FFXSR,Page1GB,RDTSCP,LM> AMD Features2=3D0x35c233ff<LAHF,CMP,SVM,ExtAPIC,CR8,ABM,SSE4A,MAS,Prefetch,OSVW= ,SKINIT,WDT,TCE,Topology,PCXC,PNXC,DBE,PL2I,MWAITX> Structured Extended Features=3D0x209c01a9<FSGSBASE,BMI1,AVX2,SMEP,BMI2,RDSEED,ADX,SMAP,CLFLUSHO= PT,SHA> XSAVE Features=3D0xf<XSAVEOPT,XSAVEC,XINUSE,XSAVES> SVM: NP,NRIP,VClean,AFlush,DAssist,NAsids=3D32768 TSC: P-state invariant, performance statistics As you can see, I don't have "IBPB" or "STIBP". I have checked hw.ibrs_active: hw.ibrs_active: 0 If I can provide or you need further information, please let me know. Thanx Frank Am Tue, 8 May 2018 21:39:48 +1000 schrieb edenist <edenist@edenist.net>: > Hi Frank, >=20 > While the changelog from Asus is rather lean, I would wager it has to > do with spectre mitigations introduced by AMD. > Last month they announced that they had prepared a microcode update to > address variant 2, and had handed the microcode to motherboard vendors > to supply as a BIOS update. >=20 > Most of my systems are AMD, though I've yet to see this microcode > update personally yet due to lazy vendors. That said, it appears they > have followed intel and introduced an IBRS feature. >=20 > https://developer.amd.com/wp-content/resources/Architecture_Guidelines_Up= date_Indirect_Branch_Control.pdf >=20 > According to that document, sure enough msr 49 is for IBPB. >=20 > If you check your CPU features in your kernel logs, if the CPU has the > IBRS feature, both IBPB and STIBP will appear under Structured > Extended Features. > On an intel system I have with updated microcode, it shows the > following: Structured Extended Features3=3D0xc000000<IBPB,STIBP> >=20 > I'd then check the hw.ibrs_active sysctl to see if it is in use. If > so, it can be disabled with hw.ibrs_disable. >=20 > Someone more knowledgeable on the inner workings of bhyve can likely > give more info on the error itself, but I'm unsure if these features > have even been exposed to guests yet. >=20 > Josh --Sig_/6thf5eBHeeKbdbxUgz+kI0Y Content-Type: application/pgp-signature Content-Description: Digitale Signatur von OpenPGP -----BEGIN PGP SIGNATURE----- iF0EARECAB0WIQSnmuRRu7yN/9fhJZSngGwyW6douQUCWvayCAAKCRCngGwyW6do ubEgAJsH9nltcMkjo6UEiMlvkaOjBngqogCdGCXfIkqbe3eniDbI2zmHWLDGz6E= =wjHB -----END PGP SIGNATURE----- --Sig_/6thf5eBHeeKbdbxUgz+kI0Y--
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