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From: Yu Zhao <yuzhao@google.com>
To: pbonzini@redhat.com
Cc: chenhuacai@kernel.org, chenhuacai@loongson.cn,
	jiaxun.yang@flygoat.com, kvm@vger.kernel.org,
	linux-mips@vger.kernel.org, stable@vger.kernel.org,
	tsbogend@alpha.franken.de
Subject: Re: [PATCH] MIPS: KVM: Fix NULL pointer dereference
Date: Wed, 28 Jun 2023 18:07:29 -0600	[thread overview]
Message-ID: <20230629000729.1223067-1-yuzhao@google.com> (raw)
In-Reply-To: <CABgObfYLnhW0qrPvFnMW_B9xZzLF6Ysn2uL4w9B815fUNVKK5A@mail.gmail.com>

On Mon, Jun 26, 2023 at 6:33 AM Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> On Mon, Jun 26, 2023 at 9:59 AM Huacai Chen <chenhuacai@loongson.cn> wrote:
> >
> > After commit 45c7e8af4a5e3f0bea4ac209 ("MIPS: Remove KVM_TE support") we
> > get a NULL pointer dereference when creating a KVM guest:
>
> To be honest, a bug that needed 2 years to be reproduced is probably a
> sign that KVM/MIPS has no users. Any objections to removing it
> altogether?

ACK:
1. It's still broken after this patch [1]. The most well-tested MIPS
   distros, i.e., Debian/OpenWrt, have CONFIG_KVM=n. (The latter doesn't
   even provide the QEMU package on MIPS.)
2. Burden on QEMU dev. There is no guarantee that QEMU would work with
   KVM even if we could fix the kernel -- it actually does not until
   v8.0 [1], which is by luck:

   commit a844873512400fae6bed9e87694dc96ff2f15f39
   Author: Paolo Bonzini <pbonzini@redhat.com>
   Date:   Sun Dec 18 01:06:45 2022 +0100
   
       mips: Remove support for trap and emulate KVM
       
       This support was limited to the Malta board, drop it.
       I do not have a machine that can run VZ KVM, so I am assuming
       that it works for -M malta as well.

   (The latest Debian stable only ships v7.2.)

[1] https://lore.kernel.org/r/ZI0R76Fx25Q2EThZ@google.com/

  parent reply	other threads:[~2023-06-29  0:07 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-26  7:49 [PATCH] MIPS: KVM: Fix NULL pointer dereference Huacai Chen
2023-06-26 10:28 ` Philippe Mathieu-Daudé
2023-06-28  7:34   ` Huacai Chen
2023-06-26 10:33 ` Paolo Bonzini
2023-06-26 12:44   ` Huacai Chen
2023-06-29  0:07   ` Yu Zhao [this message]
2023-06-29  6:24     ` Huacai Chen
2023-06-29  8:54       ` Yu Zhao
2023-06-29 14:58   ` Jiaxun Yang

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