Messages in this thread | | | Subject | Re: [PATCH 02/16] x86/entry/32: Enter the kernel via trampoline stack | From | Andrew Cooper <> | Date | Wed, 17 Jan 2018 14:04:22 +0000 |
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On 17/01/18 09:02, Joerg Roedel wrote: > Hi Boris, > > thanks for testing this :) > > On Tue, Jan 16, 2018 at 09:47:06PM -0500, Boris Ostrovsky wrote: >> On 01/16/2018 11:36 AM, Joerg Roedel wrote: >>> +.macro SWITCH_TO_KERNEL_STACK nr_regs=0 check_user=0 >> >> This (and next patch's SWITCH_TO_ENTRY_STACK) need X86_FEATURE_PTI check. >> >> With those macros fixed I was able to boot 32-bit Xen PV guest. > Hmm, on bare metal the stack switch happens regardless of the > X86_FEATURE_PTI feature being set, because we always program tss.sp0 > with the systenter stack. How is the kernel entry stack setup on xen-pv? > I think something is missing there instead.
There is one single stack registered with Xen, on which you get a normal exception frame in all cases, even via the registered (virtual) syscall/sysenter/failsafe handlers.
~Andrew
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