linux-kernel - Re: [PATCH 1/2] KVM: arm64: Dump instruction on hyp panic

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Message-ID: <CAFgf54q3KVOZ0Tji+dpnvnPCbvpN4z1Yhm5jfpEmDPhndo6bXA@mail.gmail.com>
Date: Thu, 31 Jul 2025 14:05:36 +0100
From: Mostafa Saleh <smostafa@...gle.com>
To: Kunwu Chan <kunwu.chan@...ux.dev>
Cc: linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] KVM: arm64: Dump instruction on hyp panic

Hi Kunwu,

On Thu, Jul 31, 2025 at 1:59 PM Kunwu Chan <kunwu.chan@...ux.dev> wrote:
>
> Hi Mostafa,
> On 2025/7/18 07:47, Mostafa Saleh wrote:
>
> ... ....
>
> > +     /* Dump the faulting instruction */
> > +     if (!is_protected_kvm_enabled() ||
> > +         IS_ENABLED(CONFIG_NVHE_EL2_DEBUG))
> > +             dump_instr(panic_addr + kaslr_offset());
> > +
> This part seem like unnecessary, cause it'll be remove in patch 2(Only
> the comment left).
>

Yes, the idea is that the first patch adds that only for CONFIG_NVHE_EL2_DEBUG
while the second does that for all configs, I split it this way as
doing that with stage-2
requires intrusive changes, so at least this patch can be picked
separately if needed.

> >       /*
> >        * Hyp has panicked and we're going to handle that by panicking the
> >        * kernel. The kernel offset will be revealed in the panic so we're
> Another confusion is that no similar wording to what you mentioned in
> the cover—specifically "Cannot dump pKVM nVHE stacktrace:
> !CONFIG_PROTECTED_NVHE_STACKTRACE"—has been found in the code.
>
I am not sure I follow, this has nothing to do with
"CONFIG_PROTECTED_NVHE_STACKTRACE"
This series added the print for for instructions as:
[   12.016044] Code: a8c17bfd d50323bf d65f03c0 d503245f (d4210000)

All other prints are from already existing code.

Thanks,
Mostafa


>
> --
> Thanks,
>         Kunwu Chan.
>