From: Waiman Long <longman@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>, Joerg Roedel <joro@8bytes.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, "H . Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, linux-kernel@vger.kernel.org, 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>, 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: [PATCH 06/16] x86/mm/ldt: Reserve high address-space range for the LDT
Date: Tue, 16 Jan 2018 12:34:36 -0500 [thread overview]
Message-ID: <13a45e59-5969-2fdb-25cd-adcd5298784b@redhat.com> (raw)
In-Reply-To: <20180116173115.GG2228@hirez.programming.kicks-ass.net>
On 01/16/2018 12:31 PM, Peter Zijlstra wrote:
> On Tue, Jan 16, 2018 at 06:13:43PM +0100, Joerg Roedel wrote:
>> Hi Peter,
>>
>> On Tue, Jan 16, 2018 at 05:52:13PM +0100, Peter Zijlstra wrote:
>>> On Tue, Jan 16, 2018 at 05:36:49PM +0100, Joerg Roedel wrote:
>>>> From: Joerg Roedel <jroedel@suse.de>
>>>>
>>>> Reserve 2MB/4MB of address space for mapping the LDT to
>>>> user-space.
>>> LDT is 64k, we need 2 per CPU, and NR_CPUS <= 64 on 32bit, that gives
>>> 64K*2*64=8M > 2M.
>> Thanks, I'll fix that in the next version.
> Just lower the max SMP setting until it fits or something. 32bit is too
> address space starved for lots of CPU in any case, 64 CPUs on 32bit is
> absolutely insane.
Maybe we can just scale the amount of reserved space according to the
current NR_CPUS setting. In this way, we won't waste more memory than is
necessary.
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next prev parent reply other threads:[~2018-01-16 17:35 UTC|newest]
Thread overview: 93+ 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 ` [PATCH 01/16] x86/entry/32: Rename TSS_sysenter_sp0 to TSS_sysenter_stack Joerg Roedel
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 20:30 ` Thomas Gleixner
2018-01-16 22:37 ` Andy Lutomirski
2018-01-16 22:45 ` Andy Lutomirski
2018-01-17 9:18 ` Joerg Roedel
2018-01-17 18:10 ` Andy Lutomirski
2018-01-19 9:55 ` Joerg Roedel
2018-01-19 16:30 ` Andy Lutomirski
2018-01-22 10:11 ` Joerg Roedel
2018-01-22 17:46 ` Andy Lutomirski
2018-01-17 2:47 ` Boris Ostrovsky
2018-01-17 9:02 ` Joerg Roedel
2018-01-17 14:04 ` Andrew Cooper
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 22:48 ` Andy Lutomirski
2018-01-17 9:24 ` Joerg Roedel
2018-01-17 13:57 ` Brian Gerst
2018-01-17 14:00 ` Brian Gerst
2018-01-17 14:14 ` Joerg Roedel
2018-01-17 14:45 ` Josh Poimboeuf
2018-01-17 14:10 ` Joerg Roedel
2018-01-17 18:12 ` Andy Lutomirski
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 22:46 ` Andy Lutomirski
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 ` [PATCH 06/16] x86/mm/ldt: Reserve high address-space range for the LDT Joerg Roedel
2018-01-16 16:52 ` Peter Zijlstra
2018-01-16 17:13 ` Joerg Roedel
2018-01-16 17:31 ` Peter Zijlstra
2018-01-16 17:34 ` Waiman Long [this message]
2018-01-16 22:51 ` Andy Lutomirski
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 18:03 ` Dave Hansen
2018-01-16 19:11 ` Joerg Roedel
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
2018-01-17 23:43 ` Andy Lutomirski
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 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 18:06 ` Dave Hansen
2018-01-16 19:41 ` Joerg Roedel
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 ` [PATCH 12/16] x86/mm/pae: Populate the user page-table with user pgd's Joerg Roedel
2018-01-16 18:11 ` Dave Hansen
2018-01-16 19:44 ` Joerg Roedel
2018-01-16 21:10 ` Thomas Gleixner
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 ` [PATCH 14/16] x86/mm/legacy: Populate the user page-table with user pgd's Joerg Roedel
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 ` [PATCH 16/16] x86/pti: Allow CONFIG_PAGE_TABLE_ISOLATION for x86_32 Joerg Roedel
2018-01-16 18:14 ` [RFC PATCH 00/16] PTI support for x86-32 Dave Hansen
2018-01-16 19:46 ` Joerg Roedel
2018-01-16 18:59 ` Linus Torvalds
2018-01-16 19:02 ` Dave Hansen
2018-01-16 19:21 ` Andrew Cooper
2018-01-16 19:55 ` Joerg Roedel
2018-01-16 21:20 ` Thomas Gleixner
2018-01-17 9:55 ` Joerg Roedel
2018-01-16 22:26 ` Andy Lutomirski
2018-01-17 9:33 ` Joerg Roedel
2018-01-19 10:55 ` Pavel Machek
2018-01-19 11:07 ` Joerg Roedel
2018-01-19 12:58 ` Pavel Machek
2018-01-21 20:13 ` Nadav Amit
2018-01-21 20:44 ` Nadav Amit
2018-01-21 23:46 ` Nadav Amit
2018-01-22 2:11 ` Linus Torvalds
2018-01-22 2:20 ` hpa
2018-01-22 20:14 ` Linus Torvalds
2018-01-22 21:10 ` H. Peter Anvin
2018-01-23 14:38 ` Alan Cox
2018-01-22 2:27 ` Nadav Amit
2018-01-22 8:56 ` Joerg Roedel
2018-01-23 14:57 ` Alan Cox
2018-01-25 17:09 ` Alan Cox
2018-01-26 12:36 ` Joerg Roedel
2018-01-22 9:55 ` David Laight
2018-01-22 10:04 ` Joerg Roedel
2018-01-24 18:58 ` Krzysztof Mazur
2018-01-25 22:09 ` Nadav Amit
2018-01-26 9:28 ` Krzysztof Mazur
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