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From: Dave Hansen <dave.hansen@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@kernel.org>,
	Borislav Petkov <bp@alien8.de>, Brian Gerst <brgerst@gmail.com>,
	Denys Vlasenko <dvlasenk@redhat.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Rik van Riel <riel@redhat.com>,
	daniel.gruss@iaik.tugraz.at, hughd@google.com,
	keescook@google.com, linux-mm@kvack.org,
	michael.schwarz@iaik.tugraz.at, moritz.lipp@iaik.tugraz.at,
	richard.fellner@student.tugraz.at
Subject: Re: [patch V2 5/5] x86/kaiser: Add boottime disable switch
Date: Mon, 27 Nov 2017 10:22:52 -0800	[thread overview]
Message-ID: <24359653-5b93-7146-8f65-ac38c3af0069@linux.intel.com> (raw)
In-Reply-To: <20171126232414.645128754@linutronix.de>

On 11/26/2017 03:14 PM, Thomas Gleixner wrote:
> --- a/security/Kconfig
> +++ b/security/Kconfig
> @@ -56,7 +56,7 @@ config SECURITY_NETWORK
>  
>  config KAISER
>  	bool "Remove the kernel mapping in user mode"
> -	depends on X86_64 && SMP && !PARAVIRT
> +	depends on X86_64 && SMP && !PARAVIRT && JUMP_LABEL
>  	help
>  	  This feature reduces the number of hardware side channels by
>  	  ensuring that the majority of kernel addresses are not mapped

One of the reasons for doing the runtime-disable was to get rid of the
!PARAVIRT dependency.  I can add a follow-on here that will act as if we
did "nokaiser" whenever Xen is in play so we can remove this dependency.

I just hope Xen is detectable early enough to do the static patching.

WARNING: multiple messages have this Message-ID
From: Dave Hansen <dave.hansen@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@kernel.org>,
	Borislav Petkov <bp@alien8.de>, Brian Gerst <brgerst@gmail.com>,
	Denys Vlasenko <dvlasenk@redhat.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Rik van Riel <riel@redhat.com>,
	daniel.gruss@iaik.tugraz.at, hughd@google.com,
	keescook@google.com, linux-mm@kvack.org,
	michael.schwarz@iaik.tugraz.at, moritz.lipp@iaik.tugraz.at,
	richard.fellner@student.tugraz.at
Subject: Re: [patch V2 5/5] x86/kaiser: Add boottime disable switch
Date: Mon, 27 Nov 2017 10:22:52 -0800	[thread overview]
Message-ID: <24359653-5b93-7146-8f65-ac38c3af0069@linux.intel.com> (raw)
In-Reply-To: <20171126232414.645128754@linutronix.de>

On 11/26/2017 03:14 PM, Thomas Gleixner wrote:
> --- a/security/Kconfig
> +++ b/security/Kconfig
> @@ -56,7 +56,7 @@ config SECURITY_NETWORK
>  
>  config KAISER
>  	bool "Remove the kernel mapping in user mode"
> -	depends on X86_64 && SMP && !PARAVIRT
> +	depends on X86_64 && SMP && !PARAVIRT && JUMP_LABEL
>  	help
>  	  This feature reduces the number of hardware side channels by
>  	  ensuring that the majority of kernel addresses are not mapped

One of the reasons for doing the runtime-disable was to get rid of the
!PARAVIRT dependency.  I can add a follow-on here that will act as if we
did "nokaiser" whenever Xen is in play so we can remove this dependency.

I just hope Xen is detectable early enough to do the static patching.

--
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  parent reply	other threads:[~2017-11-27 18:22 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-26 23:14 [patch V2 0/5] x86/kaiser: Boot time disabling and debug support Thomas Gleixner
2017-11-26 23:14 ` Thomas Gleixner
2017-11-26 23:14 ` [patch V2 1/5] x86/kaiser: Respect disabled CPU features Thomas Gleixner
2017-11-26 23:14   ` Thomas Gleixner
2017-11-27  9:57   ` Peter Zijlstra
2017-11-27  9:57     ` Peter Zijlstra
2017-11-27 11:47     ` Thomas Gleixner
2017-11-27 11:47       ` Thomas Gleixner
2017-11-27 12:31       ` Brian Gerst
2017-11-27 12:31         ` Brian Gerst
2017-11-27 13:18         ` Thomas Gleixner
2017-11-27 13:18           ` Thomas Gleixner
2017-11-27 18:11   ` Dave Hansen
2017-11-27 18:11     ` Dave Hansen
2017-11-27 18:37     ` Kees Cook
2017-11-27 18:37       ` Kees Cook
2017-11-26 23:14 ` [patch V2 2/5] x86/kaiser: Simplify disabling of global pages Thomas Gleixner
2017-11-26 23:14   ` Thomas Gleixner
2017-11-27 11:49   ` Thomas Gleixner
2017-11-27 11:49     ` Thomas Gleixner
2017-11-27 18:15   ` Dave Hansen
2017-11-27 18:15     ` Dave Hansen
2017-11-27 20:28     ` Thomas Gleixner
2017-11-27 20:28       ` Thomas Gleixner
2017-11-26 23:14 ` [patch V2 3/5] x86/dump_pagetables: Check KAISER shadow page table for WX pages Thomas Gleixner
2017-11-26 23:14   ` Thomas Gleixner
2017-11-27 18:17   ` Dave Hansen
2017-11-27 18:17     ` Dave Hansen
2017-11-26 23:14 ` [patch V2 4/5] x86/mm/debug_pagetables: Allow dumping current pagetables Thomas Gleixner
2017-11-26 23:14   ` Thomas Gleixner
2017-11-27  9:41   ` Peter Zijlstra
2017-11-27  9:41     ` Peter Zijlstra
2017-11-27 10:06     ` [PATCH] vfs: Add PERM_* symbolic helpers for common file mode/permissions Ingo Molnar
2017-11-27 10:06       ` Ingo Molnar
2017-11-27 19:21       ` Linus Torvalds
2017-11-27 19:21         ` Linus Torvalds
2017-11-28 10:54         ` Ingo Molnar
2017-11-28 10:54           ` Ingo Molnar
2017-11-28 11:12         ` Ingo Molnar
2017-11-28 11:12           ` Ingo Molnar
2017-11-29  8:52           ` Michael Ellerman
2017-11-29  8:52             ` Michael Ellerman
2017-11-27 18:18   ` [patch V2 4/5] x86/mm/debug_pagetables: Allow dumping current pagetables Dave Hansen
2017-11-27 18:18     ` Dave Hansen
2017-11-26 23:14 ` [patch V2 5/5] x86/kaiser: Add boottime disable switch Thomas Gleixner
2017-11-26 23:14   ` Thomas Gleixner
2017-11-27  9:48   ` Peter Zijlstra
2017-11-27  9:48     ` Peter Zijlstra
2017-11-27 10:22     ` Peter Zijlstra
2017-11-27 10:22       ` Peter Zijlstra
2017-11-27 11:50       ` Thomas Gleixner
2017-11-27 11:50         ` Thomas Gleixner
2017-11-27 12:49         ` Peter Zijlstra
2017-11-27 12:49           ` Peter Zijlstra
2017-11-27 21:43       ` Peter Zijlstra
2017-11-27 21:43         ` Peter Zijlstra
2017-11-27 18:22   ` Dave Hansen [this message]
2017-11-27 18:22     ` Dave Hansen
2017-11-27 19:00     ` Thomas Gleixner
2017-11-27 19:00       ` Thomas Gleixner
2017-11-27 19:18       ` Josh Poimboeuf
2017-11-27 19:18         ` Josh Poimboeuf
2017-11-27 20:47         ` Thomas Gleixner
2017-11-27 20:47           ` Thomas Gleixner

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