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From: Christoph Hellwig <hch@infradead.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
	x86@kernel.org, "Kenneth R. Crudup" <kenny@panix.com>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Paolo Bonzini <pbonzini@redhat.com>, Jessica Yu <jeyu@kernel.org>,
	Fenghua Yu <fenghua.yu@intel.com>,
	Xiaoyao Li <xiaoyao.li@intel.com>, Nadav Amit <namit@vmware.com>,
	Thomas Hellstrom <thellstrom@vmware.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Tony Luck <tony.luck@intel.com>,
	Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [patch 1/2] x86,module: Detect VMX modules and disable Split-Lock-Detect
Date: Mon, 6 Apr 2020 05:23:43 -0700	[thread overview]
Message-ID: <20200406122343.GA10683@infradead.org> (raw)
In-Reply-To: <20200402124205.242674296@linutronix.de>

On Thu, Apr 02, 2020 at 02:32:59PM +0200, Thomas Gleixner wrote:
> From: Peter Zijlstra <peterz@infradead.org>
> 
> It turns out that with Split-Lock-Detect enabled (default) any VMX
> hypervisor needs at least a little modification in order to not blindly
> inject the #AC into the guest without the guest being ready for it.
> 
> Since there is no telling which module implements a hypervisor, scan the
> module text and look for the VMLAUNCH instruction. If found, the module is
> assumed to be a hypervisor of some sort and SLD is disabled.
> 
> Hypervisors, which have been modified and are known to work correctly,
> can add:
> 
>   MODULE_INFO(sld_safe, "Y");
> 
> to explicitly tell the module loader they're good.
> 
> NOTE: it is unfortunate that struct load_info is not available to the
>       arch module code, this means CONFIG_CPU_SUP_INTEL gunk is needed
>       in generic code.
> 
> NOTE: while we can 'trivially' fix KVM, we're still stuck with stuff
>       like VMware and VirtualBox doing their own thing.

This is just crazy.  We have never cared about any out tree module, why
would we care here where it creates a real complexity.  Just fix KVM
and ignore anything else.

  parent reply	other threads:[~2020-04-06 12:23 UTC|newest]

Thread overview: 79+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-02 12:32 [patch 0/2] x86: Prevent Split-Lock-Detection wreckage on VMX hypervisors Thomas Gleixner
2020-04-02 12:32 ` [patch 1/2] x86,module: Detect VMX modules and disable Split-Lock-Detect Thomas Gleixner
2020-04-02 15:23   ` [patch v2 " Peter Zijlstra
2020-04-02 16:20     ` Xiaoyao Li
2020-04-02 16:25       ` Peter Zijlstra
2020-04-02 16:39         ` Nadav Amit
2020-04-02 16:41         ` Xiaoyao Li
2020-04-02 17:34           ` Thomas Gleixner
2020-04-02 17:51             ` Sean Christopherson
2020-04-02 18:51               ` Peter Zijlstra
2020-04-02 20:23                 ` Sean Christopherson
2020-04-02 21:04                   ` Thomas Gleixner
2020-04-02 21:16                     ` Sean Christopherson
2020-04-03  8:09     ` David Laight
2020-04-03 14:33       ` Peter Zijlstra
2020-04-02 23:42   ` [patch " Rasmus Villemoes
2020-04-03 14:35     ` Jessica Yu
2020-04-03 15:21       ` Peter Zijlstra
2020-04-03 16:01         ` Sean Christopherson
2020-04-03 16:12           ` Peter Zijlstra
2020-04-03 16:16             ` David Laight
2020-04-03 16:39               ` Peter Zijlstra
2020-04-03 16:25             ` Sean Christopherson
2020-04-03 16:40               ` Peter Zijlstra
2020-04-03 16:48                 ` Nadav Amit
2020-04-03 17:21                   ` Sean Christopherson
2020-04-03 18:53         ` Thomas Gleixner
2020-04-03 20:58           ` Andy Lutomirski
2020-04-03 21:49             ` Thomas Gleixner
2020-04-03 11:29   ` kbuild test robot
2020-04-03 14:43   ` kbuild test robot
2020-04-03 16:36   ` Sean Christopherson
2020-04-03 16:41     ` Peter Zijlstra
2020-04-03 18:35       ` Jessica Yu
2020-04-06 12:23   ` Christoph Hellwig [this message]
2020-04-06 14:40     ` Peter Zijlstra
2020-04-06 15:18       ` Christoph Hellwig
2020-04-06 15:22         ` Peter Zijlstra
2020-04-06 18:27           ` Steven Rostedt
2020-04-02 12:33 ` [patch 2/2] x86/kvm/vmx: Prevent split lock detection induced #AC wreckage Thomas Gleixner
2020-04-02 15:30   ` Sean Christopherson
2020-04-02 15:44     ` Nadav Amit
2020-04-02 16:04       ` Sean Christopherson
2020-04-02 16:56     ` Thomas Gleixner
2020-04-02 15:55   ` [PATCH 0/3] x86: KVM: VMX: Add basic split-lock #AC handling Sean Christopherson
2020-04-02 15:55     ` [PATCH 1/3] KVM: x86: Emulate split-lock access as a write in emulator Sean Christopherson
2020-04-02 15:55     ` [PATCH 2/3] x86/split_lock: Refactor and export handle_user_split_lock() for KVM Sean Christopherson
2020-04-02 17:01       ` Thomas Gleixner
2020-04-02 17:19         ` Sean Christopherson
2020-04-02 19:06           ` Thomas Gleixner
2020-04-10  4:39             ` Xiaoyao Li
2020-04-10 10:21               ` Paolo Bonzini
2020-04-02 15:55     ` [PATCH 3/3] KVM: VMX: Extend VMX's #AC interceptor to handle split lock #AC in guest Sean Christopherson
2020-04-02 17:19       ` Thomas Gleixner
2020-04-02 17:40         ` Sean Christopherson
2020-04-02 20:07           ` Thomas Gleixner
2020-04-02 20:36             ` Andy Lutomirski
2020-04-02 20:48             ` Peter Zijlstra
2020-04-02 20:51             ` Sean Christopherson
2020-04-02 22:27               ` Thomas Gleixner
2020-04-02 22:40                 ` Nadav Amit
2020-04-02 23:03                   ` Thomas Gleixner
2020-04-02 23:08                   ` Steven Rostedt
2020-04-02 23:16                     ` Kenneth R. Crudup
2020-04-02 23:18                       ` Jim Mattson
2020-04-03 12:16                         ` Thomas Gleixner
2020-04-10 10:23     ` [PATCH 0/3] x86: KVM: VMX: Add basic split-lock #AC handling Paolo Bonzini
2020-04-10 11:14       ` Thomas Gleixner
2020-04-02 13:43 ` [patch 0/2] x86: Prevent Split-Lock-Detection wreckage on VMX hypervisors Kenneth R. Crudup
2020-04-02 14:32   ` Peter Zijlstra
2020-04-02 14:41     ` Kenneth R. Crudup
2020-04-02 14:46       ` Peter Zijlstra
2020-04-02 14:53         ` Kenneth R. Crudup
2020-04-02 14:37   ` Thomas Gleixner
2020-04-02 14:47     ` Nadav Amit
2020-04-02 15:11       ` Peter Zijlstra
2020-04-02 14:53 [patch 1/2] x86,module: Detect VMX modules and disable Split-Lock-Detect Andy Lutomirski
2020-04-02 15:02 ` Kenneth R. Crudup
2020-04-02 16:46   ` Thomas Gleixner

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