Messages in this thread | | | Subject | Re: [PATCH 4/4] x86,module: Detect CRn and DRn manipulation | From | Jan Kiszka <> | Date | Wed, 8 Apr 2020 10:58:53 +0200 |
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On 08.04.20 10:03, Paolo Bonzini wrote: > On 08/04/20 07:58, Jan Kiszka wrote: >>>> >>>> + if (insn_is_mov_CRn(&insn) || insn_is_mov_DRn(&insn)) { >>>> + pr_err("Module writes to CRn or DRn, please use the >>>> proper accessors: %s\n", mod->name); >>>> + return -ENOEXEC; >>>> + } >>> >>> Hmm, wont this break jailhouse? >> >> Yes, possibly. We load the hypervisor binary via request_firmware into >> executable memory and then jump into it. So most of the "suspicious" >> code is there - except two cr4_init_shadow() calls to propagate the >> non-transparent update of VMXE into that shadow. We could hide that CR4 >> flag, but that could mislead root Linux to try to use VMX while in jail. > > Why not contribute the Jailhouse loader into Linux? >
Definitely planned. But right now it would add the burden of managing the interface between loader and hypervisor carefully. Currently it is internal to Jailhouse and maintained in lock-step, without any backward compatibility.
Jan
-- Siemens AG, Corporate Technology, CT RDA IOT SES-DE Corporate Competence Center Embedded Linux
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