linux-kernel - Re: [PATCH v2 6/9] x86/kexec: set_[gi]dt() -> native_[gi]dt_invalidate() in machine_kexec

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Date:   Sat, 15 May 2021 08:30:21 -0700
From:   Andy Lutomirski <luto@...nel.org>
To:     "H. Peter Anvin" <hpa@...or.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 6/9] x86/kexec: set_[gi]dt() ->
 native_[gi]dt_invalidate() in machine_kexec_*.c

On 5/14/21 6:43 PM, H. Peter Anvin wrote:
> From: "H. Peter Anvin (Intel)" <hpa@...or.com>
> 
> These files contain private set_gdt() functions which are only used to
> invalid the gdt; machine_kexec_64.c also contains a set_idt()
> function to invalidate the idt.
> 
> phys_to_virt(0) *really* doesn't make any sense for creating an
> invalid GDT. A NULL pointer (virtual 0) makes a lot more sense;
> although neither will allow any actual memory reference, a NULL
> pointer stands out more.
> 
> Replace these calls with native_[gi]dt_invalidate().
> 
> Signed-off-by: H. Peter Anvin (Intel) <hpa@...or.com>

Acked-by: Andy Lutomirski <luto@...nel.org>