Messages in this thread | | | Subject | Re: [PATCH 23/62] x86/idt: Move IDT to data segment | From | Jürgen Groß <> | Date | Wed, 12 Feb 2020 17:28:21 +0100 |
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On 12.02.20 17:23, Andy Lutomirski wrote: > > >> On Feb 12, 2020, at 3:55 AM, Joerg Roedel <joro@8bytes.org> wrote: >> >> On Tue, Feb 11, 2020 at 02:41:25PM -0800, Andy Lutomirski wrote: >>>> On Tue, Feb 11, 2020 at 5:53 AM Joerg Roedel <joro@8bytes.org> wrote: >>>> >>>> From: Joerg Roedel <jroedel@suse.de> >>>> >>>> With SEV-ES, exception handling is needed very early, even before the >>>> kernel has cleared the bss segment. In order to prevent clearing the >>>> currently used IDT, move the IDT to the data segment. >>> >>> Ugh. At the very least this needs a comment in the code. >> >> Yes, right, added a comment for that. >> >>> I had a patch to fix the kernel ELF loader to clear BSS, which would >>> fix this problem once and for all, but it didn't work due to the messy >>> way that the decompressor handles memory. I never got around to >>> fixing this, sadly. >> >> Aren't there other ways of booting (Xen-PV?) which don't use the kernel >> ELF loader? > > Dunno. I would hope the any sane loader would clear BSS before executing anything. This isn’t currently the case, though. Oh well.
Xen-PV is clearing BSS as the very first action.
Juergen
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