From: Dave Hansen <dave.hansen@linux.intel.com> To: Linus Torvalds <torvalds@linux-foundation.org> Cc: "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>, linux-mm <linux-mm@kvack.org>, "Andrew Lutomirski" <luto@kernel.org>, "Kees Cook" <keescook@google.com>, "Hugh Dickins" <hughd@google.com>, "Jürgen Groß" <jgross@suse.com>, "the arch/x86 maintainers" <x86@kernel.org> Subject: Re: [PATCH 0/3] Use global pages with PTI Date: Thu, 15 Feb 2018 10:13:05 -0800 [thread overview] Message-ID: <648e1bf1-c03e-2f1a-8a08-3763e6211ad3@linux.intel.com> (raw) In-Reply-To: <CA+55aFy8k_zSJ_ASyzkA9C-jLV4mZsHpv1sOxJ9qpvfS_P6eMg@mail.gmail.com> On 02/15/2018 09:47 AM, Linus Torvalds wrote: > On Thu, Feb 15, 2018 at 5:20 AM, Dave Hansen > <dave.hansen@linux.intel.com> wrote: >> >> During the switch over to PTI, we seem to have lost our ability to have >> GLOBAL mappings. > > Oops. Odd, I have this distinct memory of somebody even _testing_ the > global bit performance when I pointed out that we shouldn't just make > the bit go away entirely. > > [ goes back and looks at archives ] > > Oh, that was in fact you who did that performance test. ... > Did you perhaps re-run any benchmark numbers just to verify? Because > it's always good to back up patches that should improve performance > with actual numbers.. Nope, haven't done it yet, but I will. I wanted to double-check that there was not a reason for doing the global disabling other than the K8 TLB mismatch issues that Thomas fixed a few weeks ago: > commit 52994c256df36fda9a715697431cba9daecb6b11 > Author: Thomas Gleixner <tglx@linutronix.de> > Date: Wed Jan 3 15:57:59 2018 +0100 > > x86/pti: Make sure the user/kernel PTEs match > > Meelis reported that his K8 Athlon64 emits MCE warnings when PTI is > enabled: > > [Hardware Error]: Error Addr: 0x0000ffff81e000e0 > [Hardware Error]: MC1 Error: L1 TLB multimatch. > [Hardware Error]: cache level: L1, tx: INSN
WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave.hansen@linux.intel.com> To: Linus Torvalds <torvalds@linux-foundation.org> Cc: "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>, linux-mm <linux-mm@kvack.org>, "Andrew Lutomirski" <luto@kernel.org>, "Kees Cook" <keescook@google.com>, "Hugh Dickins" <hughd@google.com>, "Jürgen Groß" <jgross@suse.com>, "the arch/x86 maintainers" <x86@kernel.org> Subject: Re: [PATCH 0/3] Use global pages with PTI Date: Thu, 15 Feb 2018 10:13:05 -0800 [thread overview] Message-ID: <648e1bf1-c03e-2f1a-8a08-3763e6211ad3@linux.intel.com> (raw) In-Reply-To: <CA+55aFy8k_zSJ_ASyzkA9C-jLV4mZsHpv1sOxJ9qpvfS_P6eMg@mail.gmail.com> On 02/15/2018 09:47 AM, Linus Torvalds wrote: > On Thu, Feb 15, 2018 at 5:20 AM, Dave Hansen > <dave.hansen@linux.intel.com> wrote: >> >> During the switch over to PTI, we seem to have lost our ability to have >> GLOBAL mappings. > > Oops. Odd, I have this distinct memory of somebody even _testing_ the > global bit performance when I pointed out that we shouldn't just make > the bit go away entirely. > > [ goes back and looks at archives ] > > Oh, that was in fact you who did that performance test. ... > Did you perhaps re-run any benchmark numbers just to verify? Because > it's always good to back up patches that should improve performance > with actual numbers.. Nope, haven't done it yet, but I will. I wanted to double-check that there was not a reason for doing the global disabling other than the K8 TLB mismatch issues that Thomas fixed a few weeks ago: > commit 52994c256df36fda9a715697431cba9daecb6b11 > Author: Thomas Gleixner <tglx@linutronix.de> > Date: Wed Jan 3 15:57:59 2018 +0100 > > x86/pti: Make sure the user/kernel PTEs match > > Meelis reported that his K8 Athlon64 emits MCE warnings when PTI is > enabled: > > [Hardware Error]: Error Addr: 0x0000ffff81e000e0 > [Hardware Error]: MC1 Error: L1 TLB multimatch. > [Hardware Error]: cache level: L1, tx: INSN -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2018-02-15 18:13 UTC|newest] Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-02-15 13:20 [PATCH 0/3] Use global pages with PTI Dave Hansen 2018-02-15 13:20 ` Dave Hansen 2018-02-15 13:20 ` [PATCH 1/3] x86/mm: factor out conditional pageattr PTE bit setting code Dave Hansen 2018-02-15 13:20 ` Dave Hansen 2018-02-15 13:20 ` [PATCH 2/3] x86/mm: introduce __PAGE_KERNEL_GLOBAL Dave Hansen 2018-02-15 13:20 ` Dave Hansen 2018-02-16 17:47 ` Nadav Amit 2018-02-16 17:47 ` Nadav Amit 2018-02-16 18:03 ` Dave Hansen 2018-02-16 18:03 ` Dave Hansen 2018-02-16 18:25 ` Nadav Amit 2018-02-16 18:25 ` Nadav Amit 2018-02-16 19:06 ` Dave Hansen 2018-02-16 19:06 ` Dave Hansen 2018-02-16 19:54 ` Nadav Amit 2018-02-16 19:54 ` Nadav Amit 2018-02-16 20:00 ` Dave Hansen 2018-02-16 20:00 ` Dave Hansen 2018-02-16 23:19 ` Dave Hansen 2018-02-16 23:19 ` Dave Hansen 2018-02-15 13:20 ` [PATCH 3/3] x86/pti: enable global pages for shared areas Dave Hansen 2018-02-15 13:20 ` Dave Hansen 2018-02-15 17:47 ` [PATCH 0/3] Use global pages with PTI Linus Torvalds 2018-02-15 17:47 ` Linus Torvalds 2018-02-15 18:13 ` Dave Hansen [this message] 2018-02-15 18:13 ` Dave Hansen 2018-02-15 23:55 ` Dave Hansen 2018-02-15 23:55 ` Dave Hansen -- strict thread matches above, loose matches on Subject: below -- 2018-02-13 23:19 Dave Hansen
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