boka re iVatsvagiri kubva kuGraz University of Technology (Austria), yaimbozivikanwa nekugadzira MDS, NetSpectre, Throwhammer uye ZombieLoad kurwisa, yakaratidza kurwiswa kwechiteshi chitsva (CVE-2021-46778) mune AMD processor's scheduler queue inoshandiswa kuronga kuitwa kwemirairo muzvikamu zvakasiyana zvekuuraya zveCPU.
Kurwiswa, kunonzi SQUIP, inobvumira kuona iyo data inoshandiswa mukuverenga mune imwe maitiro kana muchina chaiwo kana kuronga yakavanzika yekutaurirana chiteshi pakati pemaitiro kana chaiwo michina inobvumira data kuchinjana pasina kuenda kuburikidza nehurongwa hwekutonga nzira.
ari AMD CPUs yakavakirwa pa1st, 2nd uye 3rd Zen microarchitectures chizvarwa (AMD Ryzen 2000-5000, AMD Ryzen Threadripper, AMD Athlon 3000, AMD EPYC) Vari kubatwa apo teknolojia yeSimultaneous Multithreading (SMT) inoshandiswa.
MaCPU emazuva ano anoshandisa superscalar dhizaini, apo mirairo yakawanda inoitwa panguva imwe chete kuti iwedzere kuita. Aya maCPU anoita mirairo mupombi kuburikidza nematanho akati wandei: (1) kutora, (2) decode, (3) chirongwa/ita, uye (4) kutora.
Kurwiswa kwakavakirwa pakuongorora nhanho yekuitika kwekukakavadzana (nhanho yekukakavadzana) mumitsetse yakasiyana yekuronga uye inoitwa kuburikidza nechiyero chekunonoka kana uchitanga cheki mashandiro anoitwa mune imwe SMT tambo pane imwecheteyo yemuviri CPU. Kuongorora zvirimo, iyo Prime + Probe nzira yakashandiswa, iyo inosanganisira kuzadza mutsara neseti yemareferenzi uye kuona shanduko nekuyera nguva yekuwana kwavari panguva yekurodha zvakare.
Iyo purogiramu/yekuita nhanho inogona kugadzirisa mirairo kunze kwekurongeka kuti iwedzere nhanho yekuraira kufanana. Isu tinotsanangura muchidimbu chimwe nechimwe chezvikamu izvi:
-Tsvaga. Iyo CPU inotsvaga rairo rinotevera rekuita kubva kuL1i cache.
-Decode. Kuti ubvumire kuuraya kwakanaka, iwo mirairo yakawanikwa (macro mashandiro) inogadziriswa mune imwechete kana anopfuura akareruka mamicrooperations (µops) uye anoiswa mu µop mutsara. Aya ma µops anodyiswa kumashure, kwaanorongwa uye kuurayiwa.
-Kuronga/Kumhanya. Iyo scheduler (s) inochengeta iyo µops yakagadzirira kuurayiwa (iine zviripo zvekushandisa) uye zvine simba kuronga iwo (kunze kwehurongwa) kune anowanikwa ekuuraya zvikamu. CPU musimboti ine akawanda execution units uye inogona kuva neakawanda arithmetic uye logic units (ALUs), bazi execution units (BRUs), kero chizvarwa zvikamu (AGUs).
Munguva yekuyedza, vatsvakurudzi vakakwanisa kunyatsogadzira zvakare 4096-bit yakavanzika RSA kiyi inoshandiswa kugadzira masiginecha edhijitari uchishandisa mbedTLS 3.0 cryptographic library, inoshandisa iyo Montgomery algorithm kusimudza nhamba kune simba modulus. 50.500 marata aidiwa kuti aone kiyi.
Nguva yekurwisa yese yakatora maminetsi makumi matatu nemasere. Misiyano yekurwisa iyo inopa kuvuza pakati pemaitiro akasiyana uye chaiwo michina inodzorwa neKVM hypervisor inoratidzwa. Zvinoratidzwa zvakare kuti nzira yacho inogona kushandiswa kurongedzera yakavanzika data kuchinjirwa pakati pemashini chaiwo pachiyero che 0,89 Mbit / s uye pakati pemaitiro pachiyero che 2,70 Mbit / s nekukanganisa mwero isingasviki 0,8, XNUMX%.
Iyo CPU musimboti yakakamurwa kuita akawanda anonzwisisika cores, kana shinda, ichiita yakazvimiririra yekuraira hova asi kugovera zviwanikwa zvakaita seL1i cache. µops eshinda idzi zvakare anogovera mayuniti ekuuraya zvine simba kubvumira kushandiswa kwepamusoro kwese. Kupatsanurwa kwezvikamu zvakasiyana zve kernel.
Inoitwa kuburikidza nemakwikwi ekutsinhanisa. AMD Zen zvivakwa zvinobvumira tambo mbiri
per core. Idzi tambo dzinogona kubva kuchirongwa chimwe chete kana kubva kune dzakasiyana zvirongwa, sekutungamirwa neiyo inoshanda sisitimu.
Intel processors haibatike kurwisa nekuti vanoshandisa imwe yekuronga mutsara, nepo AMD inotambura processors vachishandisa yakaparadzana mitsetse kune yega yega yekuuraya unit.
Semhinduro yekuvharisa kuburitswa kweruzivo, AMD yakakurudzirwa ivo vagadziri shandisa maalgorithms ayo anogara achiita masvomhu masvomhu munguva isingaperi, zvisinei nemhando yedata iri kugadziriswa, uye zvakare kudzivirira kufongora kwakavakirwa pane zvakavanzika data.
Chekupedzisira, kana iwe uchida kukwanisa kuziva zvakawanda nezvazvo, unogona kubvunza iwo ruzivo mu next link.