Iqembu labacwaningi abavela emanyuvesi aseShayina naseMelika lihlonze ubungozi obusha ku-Intel processors okuholela ekuvuzeni okuvela eceleni kolwazi mayelana nomphumela wemisebenzi eqagelayo, engasetshenziswa, isibonelo, ukuhlela isiteshi sokuxhumana esifihliwe phakathi kwezinqubo noma thola ukuvuza ngesikhathi sokuhlaselwa kwe-Meltdown.
Ingqikithi yokuba sengozini iwukuthi uguquko kurejista yephrosesa ye-EFLAGS eyenzeka ngenxa yokwenziwa kokuqagela kwemiyalo kuthinta isikhathi sokwenziwa esilandelayo semiyalelo ye-JCC (yeqa lapho izimo ezishiwo zifinyelelwa). Imisebenzi eqagelayo ayiqedi futhi umphumela uyalahlwa, kodwa ushintsho olulahliwe lwe-EFLAGS lunganqunywa ngokuhlaziya isikhathi sokwenziwa semiyalelo ye-JCC. Imisebenzi yokuqhathanisa eyenziwa ngemodi yokuqagela ngaphambi koshintsho, uma iphumelele, ibangela ukubambezeleka okuncane okungalinganiswa futhi kusetshenziswe njengophawu lokukhetha okuqukethwe.
Ngokungafani nokunye ukuhlasela okufanayo kwesiteshi esiseceleni, indlela entsha ayihlaziyi izinguquko esikhathini sokufinyelela kudatha egcinwe kunqolobane nengagciniwe futhi ayidingi isigaba sokusetha kabusha irejista ye-EFLAGS esimweni sayo sokuqala, okwenza kube nzima ukuthola nokuvimbela ukuhlasela. Njengomboniso, abacwaningi basebenzise okuhlukile kokuhlasela kwe-Meltdown, besebenzisa indlela entsha yokuthola ulwazi mayelana nomphumela womsebenzi wokuqagela. Ukusebenza kwendlela yokuhlela ukuvuza kolwazi ngesikhathi sokuhlasela kwe-Meltdown kuboniswe ngempumelelo kumasistimu ane-Intel Core i7-6700 ne-i7-7700 CPU endaweni eno-Ubuntu 22.04 kanye ne-Linux kernel 5.15. Kuhlelo olune-Intel i9-10980XE CPU, ukuhlasela kwenziwa kancane.
Ukuba sengozini kwe-Meltdown kusekelwe eqinisweni lokuthi phakathi nokuqagelwa kwemiyalelo, iphrosesa ingafinyelela indawo yedatha eyimfihlo bese ilahla umphumela ngenxa yokuthi amalungelo amisiwe avimbela ukufinyelela okunjalo kusukela kunqubo yomsebenzisi. Kulolu hlelo, ibhulokhi eyenziwe ngokuqagela ihlukaniswa nekhodi eyinhloko yigatsha elinemibandela, elihlala livutha ezimweni zangempela, kodwa ngenxa yokuthi isitatimende esinemibandela sisebenzisa inani elibaliwe umprosesa angalazi ngesikhathi sokukhishwa kwangaphambili. ikhodi, zonke izinketho zegatsha zenziwa ngokuqagela.
Kunguqulo yakudala ye-Meltdown, njengoba inqolobane efanayo isetshenziselwa imisebenzi eyenziwe ngokucatshangelwa njengemiyalo evame ukwenziwa, kungenzeka ngesikhathi sokuqagela ukusetha omaka kunqolobane ebonisa okuqukethwe kwezingcezu ngazinye endaweni yenkumbulo evaliwe, bese emva kwalokho. thola ngekhodi evame ukusetshenziswa incazelo yazo ngokuhlaziya isikhathi sokufinyelela kudatha egcinwe kunqolobane nengagciniwe. Okuhlukile okusha kusebenzisa ushintsho kurejista ye-EFLAGS njengomaka ovuzayo. Ekubonisweni kwesiteshi esiyimfihlo, inqubo eyodwa ilungise idatha edluliselwe ukudala izimo zokushintsha okuqukethwe kwerejista ye-EFLAGS, futhi enye inqubo yahlaziya ushintsho ngesikhathi sokwenziwa komyalelo we-JCC ukuze kudalwe kabusha idatha edluliswe inqubo yokuqala.
Source: opennet.ru