On 12.02.20 17:23, Andy Lutomirski wrote:
On Feb 12, 2020, at 3:55 AM, Joerg Roedel <joro@xxxxxxxxxx> 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@xxxxxxxxxx> wrote:
From: Joerg Roedel <jroedel@xxxxxxx>
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
