Iqela le-iAbaphandi kwiYunivesithi yaseGraz yeTekhnoloji (I-Austria), eyayisaziwa ngaphambili ngokuphuhlisa i-MDS, i-NetSpecter, i-Throwhammer kunye ne-ZombieLoad ukuhlaselwa, iveze uhlaselo lwetshaneli esecaleni (CVE-2021-46778) kumgca wenkqubo ye-AMD esetyenziselwa ukucwangcisa ukuphunyezwa kwemiyalelo kwiiyunithi ezahlukeneyo zokwenziwa ze-CPU.
Uhlaselo, lwabizwa I-SQUIP, ikuvumela ukuba unqume idatha esetyenziswe kwizibalo kwenye inkqubo okanye umatshini wenyani okanye uququzelele umjelo wonxibelelwano ofihliweyo phakathi kweenkqubo okanye oomatshini benyani abavumela ukuba idatha itshintshiswe ngaphandle kokuhamba ngeendlela zokulawula ukufikelela kwenkqubo.
Las Ii-CPU ze-AMD ezisekwe kwi-1st, 2nd kunye ne-3rd Zen microarchitectures isizukulwana (AMD Ryzen 2000-5000, AMD Ryzen Threadripper, AMD Athlon 3000, AMD EPYC) Ngaba bayachaphazeleka xa kusetyenziswa iteknoloji yeSimiltaneous Multithreading (SMT).
IiCPU zanamhlanje zisebenzisa uyilo oluphezulu, apho imiyalelo emininzi isenziwa ngaxeshanye ukwandisa ukusebenza. Ezi CPUs ziqhuba imiyalelo kumbhobho ngokusebenzisa izigaba ezininzi: (1) ukulanda, (2) ukucacisa, (3) ishedyuli / yenza, kwaye (4) umhlalaphantsi.
Uhlaselo lusekwe ekuvavanyeni umgangatho wokwenzeka kwengxabano (inqanaba losukuzwano) kwimigca eyahlukeneyo yomcwangcisi kwaye yenziwa ngokulinganisa ukulibaziseka xa kuqaliswa imisebenzi yokukhangela eyenziwa kwenye intambo ye-SMT kwi-CPU efanayo yomzimba. Ukuhlalutya umxholo, kusetyenziswe indlela ye-Prime + Probe, ebandakanya ukuzalisa umgca ngeseti yamaxabiso ereferensi kunye nokumisela utshintsho ngokulinganisa ixesha lokufikelela kubo ngexesha lokulayisha kwakhona.
Ishedyuli/inqanaba lokwenziwa lingenza imiyalelo engaphandle kwe-odolo ukwandisa ukuhambelana kwenqanaba lomyalelo. Sichaza ngokufutshane inqanaba ngalinye kula:
-Njonga i. I-CPU ijonge umyalelo olandelayo oza kuwusebenzisa kwi-cache ye-L1i.
-Decode. Ukwenza uphumezo olusebenzayo, imiyalelo ethathiweyo (imisebenzi enkulu) inqunyulwa ibe yi-microoperations ezininzi ezilula (µops) kwaye zibekwe kumgca µop. Ezi µops zondliwa ngasemva, apho zicwangciswe kwaye ziphunyezwe.
-Shedyuli/Phumeza. Um(aba) umkhondo apho µops zilungele ukuphunyezwa (zinamagalelo akhoyo) kwaye zicwangciswe ngokuguquguqukayo (ngaphandle kocwangco) kwiiyunithi zophumezo ezikhoyo. I-CPU engundoqo ineeyunithi ezininzi zokubulawa kwaye ingaba neeyunithi ezininzi ze-arithmetic kunye neengqiqo (ALU), amasebe eeyunithi zokubulawa (BRU), iiyunithi zokuvelisa idilesi (AGU).
Ngexesha lokulinga, abaphandi bakwazile ukwenza kwakhona ngokupheleleyo iqhosha le-RSA labucala le-4096-bit isetyenziselwa ukwenza imisayino yedijithali kusetyenziswa i-mbedTLS 3.0 yelayibrari efihlakeleyo, esebenzisa i-algorithm ye-Montgomery ukunyusa inani kwimodyuli yamandla. Kwafuneka imikhondo engama-50.500 ukuze kuqondwe isitshixo.
Ixesha lokuhlaselwa lilonke lithathe imizuzu engama-38. Izahluko zohlaselo zibonisiwe ezibonelela ngokuvuza phakathi kweenkqubo ezahlukeneyo kunye noomatshini ababonakalayo abalawulwa yi-KVM hypervisor. Kwakhona kuboniswa ukuba indlela ingasetyenziselwa ukuququzelela ukuhanjiswa kwedatha efihliweyo phakathi koomatshini benyani ngesantya se-0,89 Mbit / s naphakathi kweenkqubo ngesantya se-2,70 Mbit / s ngesantya sempazamo esingaphantsi kwe-0,8. XNUMX%.
Undoqo we-CPU wahlulwe ngokwee-cores ezininzi ezibhadlileyo okanye imisonto, uqhuba imijelo yomyalelo ozimeleyo kodwa ukwabelwana ngezixhobo ezifana ne-L1i cache. µ ii-ops ezisuka kule misonto zikwabelana ngeeyunithi zokwenziwa ngamandla ukuvumela usetyenziso olukhulu. Ukwahlula kweendawo ezahlukeneyo zekernel.
Yenziwa ngokutshintshiselana ngokhuphiswano. Uyilo lwe-AMD Zen luvumela imisonto emibini
ngondoqo ngamnye. Le misonto inokuvela kwiprogram enye okanye kwiiprogram ezahlukeneyo, njengoko zilawulwa yinkqubo yokusebenza.
Iiprosesa ze-Intel azichaphazeleki uhlaselo ngenxa yokuba basebenzisa umgca wokucwangcisa omnye, ngelixa abaqhubekeki be-AMD abasesichengeni basebenzisa imigca eyahlukeneyo kwiyunithi nganye yophumezo.
Njengesisombululo sokuthintela ukuvuza kolwazi, I-AMD iyacetyiswa abo baphuhlisi sebenzisa ii-algorithms ezisoloko zisenza izibalo zemathematika ngexesha elingatshintshiyo, kungakhathaliseki ukuba luhlobo luni lwedatha ecutshungulwayo, kwaye loo nto iphinda iphephe ukufowuna ngokusekelwe kwidatha eyimfihlo.
Okokugqibela, ukuba unomdla wokwazi ngakumbi ngayo, ungajongana neenkcukacha kwi ikhonkco elandelayo.