linux-kernel - Re: [PATCH v2] x86: disable PKU when running on Apple Virtualization

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Message-ID: <CAG8fp8Tjt2utmE79DfkETE96DnnwtvzHqEXmuYDi4O4azWQRLw@mail.gmail.com>
Date: Fri, 14 Mar 2025 08:59:49 +0900
From: Akihiro Suda <suda.kyoto@...il.com>
To: Ingo Molnar <mingo@...nel.org>
Cc: Akihiro Suda <suda.gitsendemail@...il.com>, linux-kernel@...r.kernel.org, 
	x86@...nel.org, regressions@...ts.linux.dev, aruna.ramakrishna@...cle.com, 
	tglx@...utronix.de, Akihiro Suda <akihiro.suda.cz@....ntt.co.jp>
Subject: Re: [PATCH v2] x86: disable PKU when running on Apple Virtualization

Thank you Ingo, and sorry for adding #ifdef CONFIG_ACPI

Regards,
Akihiro Suda

2025年3月14日(金) 2:02 Ingo Molnar <mingo@...nel.org>:
>
>
> * Akihiro Suda <suda.gitsendemail@...il.com> wrote:
>
> > OSPKE seems broken on Apple Virtualization.
> >
> >   WARNING: CPU: 0 PID: 1 at arch/x86/kernel/fpu/xstate.c:1003 get_xsave_addr_user+0x28/0x40
> >   (...)
> >   Call Trace:
> >    <TASK>
> >    ? get_xsave_addr_user+0x28/0x40
> >    ? __warn.cold+0x8e/0xea
> >    ? get_xsave_addr_user+0x28/0x40
> >    ? report_bug+0xff/0x140
> >    ? handle_bug+0x3b/0x70
> >    ? exc_invalid_op+0x17/0x70
> >    ? asm_exc_invalid_op+0x1a/0x20
> >    ? get_xsave_addr_user+0x28/0x40
> >    copy_fpstate_to_sigframe+0x1be/0x380
> >    ? __put_user_8+0x11/0x20
> >    get_sigframe+0xf1/0x280
> >    x64_setup_rt_frame+0x67/0x2c0
> >    arch_do_signal_or_restart+0x1b3/0x240
> >    syscall_exit_to_user_mode+0xb0/0x130
> >    do_syscall_64+0xab/0x1a0
> >    entry_SYSCALL_64_after_hwframe+0x77/0x7f
> >
> > Tested on macOS 13.5.1 running on MacBook Pro 2020 with
> > Intel(R) Core(TM) i7-1068NG7 CPU @ 2.30GHz.
> >
> > Fixes: 70044df250d0 ("x86/pkeys: Update PKRU to enable all pkeys before XSAVE")
> > Link: https://lore.kernel.org/regressions/CAG8fp8QvH71Wi_y7b7tgFp7knK38rfrF7rRHh-gFKqeS0gxY6Q@mail.gmail.com/T/#u
> > Link: https://github.com/lima-vm/lima/issues/3334
> > Signed-off-by: Akihiro Suda <akihiro.suda.cz@....ntt.co.jp>
> > ---
> > v2: check oem_table_id rather than oem_id for better robustness
>
> So this is rather weird, but I've applied the quirk as it upgrades
> broken guest side code into a boot time warning.
>
> > +     /*
> > +      * OSPKE seems broken on Apple Virtualization.
> > +      * https://lore.kernel.org/regressions/CAG8fp8QvH71Wi_y7b7tgFp7knK38rfrF7rRHh-gFKqeS0gxY6Q@mail.gmail.com/T/#u
> > +      *
> > +      * TODO: conditionally enable pku depending on the DMI BIOS version when Apple
> > +      * fixes the issue.
> > +      *
> > +      * However, this would be still not enough because DMI is missing when vmlinuz
> > +      * is directly loaded into VM.
> > +      */
> > +     if (!memcmp(acpi_gbl_FADT.header.oem_table_id, "Apple Vz", 8)) {
> > +             pr_info("pku: disabled on Apple Virtualization platform (Intel) due to a bug\n");
> > +             pku_disabled = true;
> > +     }
>
> Note that I updated the comments here (the git log gives enough
> information), plus enclosed this into #ifdef CONFIG_ACPI, as
> acpi_gbl_FADT is not available on !CONFIG_ACPI builds.
>
> Thanks,
>
>         Ingo