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From: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
To: Joerg Roedel <joro@8bytes.org>
Cc: Nadav Amit <nadav.amit@gmail.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>, "H . Peter Anvin" <hpa@zytor.com>,
	the arch/x86 maintainers <x86@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"open list:MEMORY MANAGEMENT" <linux-mm@kvack.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andy Lutomirski <luto@kernel.org>,
	Dave Hansen <dave.hansen@intel.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Juergen Gross <jgross@suse.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Borislav Petkov <bp@alien8.de>, Jiri Kosina <jkosina@suse.cz>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Brian Gerst <brgerst@gmail.com>,
	David Laight <David.Laight@aculab.com>,
	Denys Vlasenko <dvlasenk@redhat.com>,
	Eduardo Valentin <eduval@amazon.com>,
	Greg KH <gregkh@linuxfoundation.org>,
	Will Deacon <will.deacon@arm.com>,
	aliguori@amazon.com, daniel.gruss@iaik.tugraz.at,
	hughd@google.com, keescook@google.com,
	Andrea Arcangeli <aarcange@redhat.com>,
	Waiman Long <llong@redhat.com>,
	jroedel@suse.de
Subject: Re: [RFC PATCH 00/16] PTI support for x86-32
Date: Thu, 25 Jan 2018 17:09:25 +0000	[thread overview]
Message-ID: <20180125170925.1d72d587@alans-desktop> (raw)
In-Reply-To: <20180122085625.GE28161@8bytes.org>

On Mon, 22 Jan 2018 09:56:25 +0100
Joerg Roedel <joro@8bytes.org> wrote:

> Hey Nadav,
> 
> On Sun, Jan 21, 2018 at 03:46:24PM -0800, Nadav Amit wrote:
> > It does seem that segmentation provides sufficient protection from Meltdown.  
> 
> Thanks for testing this, if this turns out to be true for all affected
> uarchs it would be a great and better way of protection than enabling
> PTI.
> 
> But I'd like an official statement from Intel on that one, as their
> recommended fix is still to use PTI.

It is: we don't think segmentation works on all processors as a defence.

Alan

WARNING: multiple messages have this Message-ID (diff)
From: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
To: Joerg Roedel <joro@8bytes.org>
Cc: Nadav Amit <nadav.amit@gmail.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>, "H . Peter Anvin" <hpa@zytor.com>,
	the arch/x86 maintainers <x86@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"open list:MEMORY MANAGEMENT" <linux-mm@kvack.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andy Lutomirski <luto@kernel.org>,
	Dave Hansen <dave.hansen@intel.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Juergen Gross <jgross@suse.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Borislav Petkov <bp@alien8.de>, Jiri Kosina <jkosina@suse.cz>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Brian Gerst <brgerst@gmail.com>,
	David Laight <David.Laight@aculab.com>,
	Denys Vlasenko <dvlasenk@redhat.com>,
	Eduardo Valentin <eduval@amazon.com>,
	Greg KH <gregkh@linuxfoundation.org>,
	Will Deacon <will.deacon@arm.com>,
	aliguori@amazon.com, daniel.gruss@iaik.tugraz.at,
	hughd@google.com, keescook@google.com,
	Andrea Arcangeli <aarcange@redhat.com>,
	Waiman Long <llong@redhat.com>,
	jroedel@suse.de
Subject: Re: [RFC PATCH 00/16] PTI support for x86-32
Date: Thu, 25 Jan 2018 17:09:25 +0000	[thread overview]
Message-ID: <20180125170925.1d72d587@alans-desktop> (raw)
In-Reply-To: <20180122085625.GE28161@8bytes.org>

On Mon, 22 Jan 2018 09:56:25 +0100
Joerg Roedel <joro@8bytes.org> wrote:

> Hey Nadav,
> 
> On Sun, Jan 21, 2018 at 03:46:24PM -0800, Nadav Amit wrote:
> > It does seem that segmentation provides sufficient protection from Meltdown.  
> 
> Thanks for testing this, if this turns out to be true for all affected
> uarchs it would be a great and better way of protection than enabling
> PTI.
> 
> But I'd like an official statement from Intel on that one, as their
> recommended fix is still to use PTI.

It is: we don't think segmentation works on all processors as a defence.

Alan

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  parent reply	other threads:[~2018-01-25 17:09 UTC|newest]

Thread overview: 183+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-16 16:36 [RFC PATCH 00/16] PTI support for x86-32 Joerg Roedel
2018-01-16 16:36 ` Joerg Roedel
2018-01-16 16:36 ` [PATCH 01/16] x86/entry/32: Rename TSS_sysenter_sp0 to TSS_sysenter_stack Joerg Roedel
2018-01-16 16:36   ` Joerg Roedel
2018-01-16 18:35   ` Thomas Gleixner
2018-01-16 18:35     ` Thomas Gleixner
2018-01-16 16:36 ` [PATCH 02/16] x86/entry/32: Enter the kernel via trampoline stack Joerg Roedel
2018-01-16 16:36   ` Joerg Roedel
2018-01-16 20:30   ` Thomas Gleixner
2018-01-16 20:30     ` Thomas Gleixner
2018-01-16 22:37     ` Andy Lutomirski
2018-01-16 22:37       ` Andy Lutomirski
2018-01-16 22:45   ` Andy Lutomirski
2018-01-16 22:45     ` Andy Lutomirski
2018-01-17  9:18     ` Joerg Roedel
2018-01-17  9:18       ` Joerg Roedel
2018-01-17 18:10       ` Andy Lutomirski
2018-01-17 18:10         ` Andy Lutomirski
2018-01-19  9:55         ` Joerg Roedel
2018-01-19  9:55           ` Joerg Roedel
2018-01-19 16:30           ` Andy Lutomirski
2018-01-19 16:30             ` Andy Lutomirski
2018-01-22 10:11             ` Joerg Roedel
2018-01-22 10:11               ` Joerg Roedel
2018-01-22 17:46               ` Andy Lutomirski
2018-01-22 17:46                 ` Andy Lutomirski
2018-01-17  2:47   ` Boris Ostrovsky
2018-01-17  2:47     ` Boris Ostrovsky
2018-01-17  9:02     ` Joerg Roedel
2018-01-17  9:02       ` Joerg Roedel
2018-01-17 14:04       ` Andrew Cooper
2018-01-17 14:04         ` Andrew Cooper
2018-01-17 15:22         ` Boris Ostrovsky
2018-01-17 15:22           ` Boris Ostrovsky
2018-01-16 16:36 ` [PATCH 03/16] x86/entry/32: Leave the kernel via the " Joerg Roedel
2018-01-16 16:36   ` Joerg Roedel
2018-01-16 22:48   ` Andy Lutomirski
2018-01-16 22:48     ` Andy Lutomirski
2018-01-17  9:24     ` Joerg Roedel
2018-01-17  9:24       ` Joerg Roedel
2018-01-17 13:57       ` Brian Gerst
2018-01-17 13:57         ` Brian Gerst
2018-01-17 14:00         ` Brian Gerst
2018-01-17 14:00           ` Brian Gerst
2018-01-17 14:14           ` Joerg Roedel
2018-01-17 14:14             ` Joerg Roedel
2018-01-17 14:45             ` Josh Poimboeuf
2018-01-17 14:45               ` Josh Poimboeuf
2018-01-17 14:10         ` Joerg Roedel
2018-01-17 14:10           ` Joerg Roedel
2018-01-17 18:12           ` Andy Lutomirski
2018-01-17 18:12             ` Andy Lutomirski
2018-01-19  9:57             ` Joerg Roedel
2018-01-19  9:57               ` Joerg Roedel
2018-01-16 16:36 ` [PATCH 04/16] x86/pti: Define X86_CR3_PTI_PCID_USER_BIT on x86_32 Joerg Roedel
2018-01-16 16:36   ` Joerg Roedel
2018-01-16 22:46   ` Andy Lutomirski
2018-01-16 22:46     ` Andy Lutomirski
2018-01-17  9:26     ` Joerg Roedel
2018-01-17  9:26       ` Joerg Roedel
2018-01-16 16:36 ` [PATCH 05/16] x86/pgtable: Move pgdp kernel/user conversion functions to pgtable.h Joerg Roedel
2018-01-16 16:36   ` Joerg Roedel
2018-01-16 16:36 ` [PATCH 06/16] x86/mm/ldt: Reserve high address-space range for the LDT Joerg Roedel
2018-01-16 16:36   ` Joerg Roedel
2018-01-16 16:52   ` Peter Zijlstra
2018-01-16 16:52     ` Peter Zijlstra
2018-01-16 17:13     ` Joerg Roedel
2018-01-16 17:13       ` Joerg Roedel
2018-01-16 17:31       ` Peter Zijlstra
2018-01-16 17:31         ` Peter Zijlstra
2018-01-16 17:34         ` Waiman Long
2018-01-16 17:34           ` Waiman Long
2018-01-16 22:51     ` Andy Lutomirski
2018-01-16 22:51       ` Andy Lutomirski
2018-01-17  7:59       ` Peter Zijlstra
2018-01-17  7:59         ` Peter Zijlstra
2018-01-16 16:36 ` [PATCH 07/16] x86/mm: Move two more functions from pgtable_64.h to pgtable.h Joerg Roedel
2018-01-16 16:36   ` Joerg Roedel
2018-01-16 18:03   ` Dave Hansen
2018-01-16 18:03     ` Dave Hansen
2018-01-16 19:11     ` Joerg Roedel
2018-01-16 19:11       ` Joerg Roedel
2018-01-16 19:34       ` Thomas Gleixner
2018-01-16 19:34         ` Thomas Gleixner
2018-01-16 16:36 ` [PATCH 08/16] x86/pgtable/32: Allocate 8k page-tables when PTI is enabled Joerg Roedel
2018-01-16 16:36   ` Joerg Roedel
2018-01-17 23:43   ` Andy Lutomirski
2018-01-17 23:43     ` Andy Lutomirski
2018-01-19  9:57     ` Joerg Roedel
2018-01-19  9:57       ` Joerg Roedel
2018-01-16 16:36 ` [PATCH 09/16] x86/mm/pti: Clone CPU_ENTRY_AREA on PMD level on x86_32 Joerg Roedel
2018-01-16 16:36   ` Joerg Roedel
2018-01-16 21:03   ` Thomas Gleixner
2018-01-16 21:03     ` Thomas Gleixner
2018-01-16 16:36 ` [PATCH 10/16] x86/mm/pti: Populate valid user pud entries Joerg Roedel
2018-01-16 16:36   ` Joerg Roedel
2018-01-16 18:06   ` Dave Hansen
2018-01-16 18:06     ` Dave Hansen
2018-01-16 19:41     ` Joerg Roedel
2018-01-16 19:41       ` Joerg Roedel
2018-01-16 21:06   ` Thomas Gleixner
2018-01-16 21:06     ` Thomas Gleixner
2018-01-16 16:36 ` [PATCH 11/16] x86/mm/pgtable: Move pti_set_user_pgd() to pgtable.h Joerg Roedel
2018-01-16 16:36   ` Joerg Roedel
2018-01-16 16:36 ` [PATCH 12/16] x86/mm/pae: Populate the user page-table with user pgd's Joerg Roedel
2018-01-16 16:36   ` Joerg Roedel
2018-01-16 18:11   ` Dave Hansen
2018-01-16 18:11     ` Dave Hansen
2018-01-16 19:44     ` Joerg Roedel
2018-01-16 19:44       ` Joerg Roedel
2018-01-16 21:10   ` Thomas Gleixner
2018-01-16 21:10     ` Thomas Gleixner
2018-01-16 21:15     ` Dave Hansen
2018-01-16 21:15       ` Dave Hansen
2018-01-16 16:36 ` [PATCH 13/16] x86/mm/pti: Add an overflow check to pti_clone_pmds() Joerg Roedel
2018-01-16 16:36   ` Joerg Roedel
2018-01-16 16:36 ` [PATCH 14/16] x86/mm/legacy: Populate the user page-table with user pgd's Joerg Roedel
2018-01-16 16:36   ` Joerg Roedel
2018-01-17 23:41   ` Andy Lutomirski
2018-01-17 23:41     ` Andy Lutomirski
2018-01-16 16:36 ` [PATCH 15/16] x86/entry/32: Switch between kernel and user cr3 on entry/exit Joerg Roedel
2018-01-16 16:36   ` Joerg Roedel
2018-01-16 16:36 ` [PATCH 16/16] x86/pti: Allow CONFIG_PAGE_TABLE_ISOLATION for x86_32 Joerg Roedel
2018-01-16 16:36   ` Joerg Roedel
2018-01-16 18:14 ` [RFC PATCH 00/16] PTI support for x86-32 Dave Hansen
2018-01-16 18:14   ` Dave Hansen
2018-01-16 19:46   ` Joerg Roedel
2018-01-16 19:46     ` Joerg Roedel
2018-01-16 18:59 ` Linus Torvalds
2018-01-16 18:59   ` Linus Torvalds
2018-01-16 19:02   ` Dave Hansen
2018-01-16 19:02     ` Dave Hansen
2018-01-16 19:21   ` Andrew Cooper
2018-01-16 19:21     ` Andrew Cooper
2018-01-16 19:55   ` Joerg Roedel
2018-01-16 19:55     ` Joerg Roedel
2018-01-16 21:20 ` Thomas Gleixner
2018-01-16 21:20   ` Thomas Gleixner
2018-01-17  9:55   ` Joerg Roedel
2018-01-17  9:55     ` Joerg Roedel
2018-01-16 22:26 ` Andy Lutomirski
2018-01-16 22:26   ` Andy Lutomirski
2018-01-17  9:33   ` Joerg Roedel
2018-01-17  9:33     ` Joerg Roedel
2018-01-19 10:55 ` Pavel Machek
2018-01-19 11:07   ` Joerg Roedel
2018-01-19 11:07     ` Joerg Roedel
2018-01-19 12:58     ` Pavel Machek
2018-01-21 20:13 ` Nadav Amit
2018-01-21 20:13   ` Nadav Amit
2018-01-21 20:44   ` Nadav Amit
2018-01-21 20:44     ` Nadav Amit
2018-01-21 23:46     ` Nadav Amit
2018-01-21 23:46       ` Nadav Amit
2018-01-22  2:11       ` Linus Torvalds
2018-01-22  2:11         ` Linus Torvalds
2018-01-22  2:20         ` hpa
2018-01-22  2:20           ` hpa
2018-01-22 20:14           ` Linus Torvalds
2018-01-22 20:14             ` Linus Torvalds
2018-01-22 21:10             ` H. Peter Anvin
2018-01-22 21:10               ` H. Peter Anvin
2018-01-23 14:38               ` Alan Cox
2018-01-23 14:38                 ` Alan Cox
2018-01-22  2:27         ` Nadav Amit
2018-01-22  2:27           ` Nadav Amit
2018-01-22  8:56       ` Joerg Roedel
2018-01-22  8:56         ` Joerg Roedel
2018-01-23 14:57         ` Alan Cox
2018-01-23 14:57           ` Alan Cox
2018-01-25 17:09         ` Alan Cox [this message]
2018-01-25 17:09           ` Alan Cox
2018-01-26 12:36           ` Joerg Roedel
2018-01-26 12:36             ` Joerg Roedel
2018-01-22  9:55       ` David Laight
2018-01-22 10:04         ` Joerg Roedel
2018-01-22 10:04           ` Joerg Roedel
2018-01-24 18:58 ` Krzysztof Mazur
2018-01-24 18:58   ` Krzysztof Mazur
2018-01-25 22:09   ` Nadav Amit
2018-01-25 22:09     ` Nadav Amit
2018-01-26  9:28     ` Krzysztof Mazur
2018-01-26  9:28       ` Krzysztof Mazur

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