From: Ingo Molnar <mingo@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
x86@kernel.org, Stephen Hemminger <stephen@networkplumber.org>,
Willy Tarreau <w@1wt.eu>, Juergen Gross <jgross@suse.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [patch 5/9] x86/ioport: Reduce ioperm impact for sane usage further
Date: Thu, 7 Nov 2019 08:37:20 +0100 [thread overview]
Message-ID: <20191107073719.GD30739@gmail.com> (raw)
In-Reply-To: <20191106202806.241007755@linutronix.de>
* Thomas Gleixner <tglx@linutronix.de> wrote:
> @@ -365,19 +365,19 @@ struct tss_struct {
> struct x86_hw_tss x86_tss;
>
> /*
> - * Store the dirty size of the last io bitmap offender. The next
> - * one will have to do the cleanup as the switch out to a non
> - * io bitmap user will just set x86_tss.io_bitmap_base to a value
> - * outside of the TSS limit. So for sane tasks there is no need
> - * to actually touch the io_bitmap at all.
> + * Store the dirty byte range of the last io bitmap offender. The
> + * next one will have to do the cleanup because the switch out to a
> + * non I/O bitmap user will just set x86_tss.io_bitmap_base to a
> + * value outside of the TSS limit to not penalize tasks which do
> + * not use the I/O bitmap at all.
> */
> - unsigned int io_bitmap_prev_max;
> + unsigned int io_zerobits_start;
> + unsigned int io_zerobits_end;
>
> /*
> - * The extra 1 is there because the CPU will access an
> - * additional byte beyond the end of the IO permission
> - * bitmap. The extra byte must be all 1 bits, and must
> - * be within the limit.
> + * The extra 1 is there because the CPU will access an additional
> + * byte beyond the end of the I/O permission bitmap. The extra byte
> + * must have all bits set and must be within the TSS limit.
> */
> unsigned long io_bitmap[IO_BITMAP_LONGS + 1];
> } __aligned(PAGE_SIZE);
Note that on 32-bit kernels this blows up our CPU area calculations:
./include/linux/compiler.h:350:38: error: call to ‘__compiletime_assert_181’ declared with attribute error: BUILD_BUG_ON failed: CPU_ENTRY_AREA_PAGES * PAGE_SIZE < CPU_ENTRY_AREA_MAP_SIZE
./include/linux/compiler.h:331:4: note: in definition of macro ‘__compiletime_assert’
./include/linux/compiler.h:350:2: note: in expansion of macro ‘_compiletime_assert’
./include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
./include/linux/build_bug.h:50:2: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
arch/x86/mm/cpu_entry_area.c:181:2: note: in expansion of macro ‘BUILD_BUG_ON’
make[2]: *** [scripts/Makefile.build:265: arch/x86/mm/cpu_entry_area.o] Error 1
Thanks,
Ingo
next prev parent reply other threads:[~2019-11-07 7:37 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-06 19:34 [patch 0/9] x86/iopl: Prevent user space from using CLI/STI with iopl(3) Thomas Gleixner
2019-11-06 19:35 ` [patch 1/9] x86/ptrace: Prevent truncation of bitmap size Thomas Gleixner
2019-11-07 7:31 ` Ingo Molnar
2019-11-06 19:35 ` [patch 2/9] x86/process: Unify copy_thread_tls() Thomas Gleixner
2019-11-08 22:31 ` Andy Lutomirski
2019-11-08 23:43 ` Thomas Gleixner
2019-11-10 12:36 ` Thomas Gleixner
2019-11-10 16:56 ` Andy Lutomirski
2019-11-11 8:52 ` Peter Zijlstra
2019-11-06 19:35 ` [patch 3/9] x86/cpu: Unify cpu_init() Thomas Gleixner
2019-11-08 22:34 ` Andy Lutomirski
2019-11-06 19:35 ` [patch 4/9] x86/io: Speedup schedule out of I/O bitmap user Thomas Gleixner
2019-11-07 9:12 ` Peter Zijlstra
2019-11-07 14:04 ` Thomas Gleixner
2019-11-07 14:08 ` Thomas Gleixner
2019-11-08 22:41 ` Andy Lutomirski
2019-11-08 23:45 ` Thomas Gleixner
2019-11-09 3:32 ` Andy Lutomirski
2019-11-10 12:43 ` Thomas Gleixner
2019-11-09 0:24 ` Andy Lutomirski
2019-11-06 19:35 ` [patch 5/9] x86/ioport: Reduce ioperm impact for sane usage further Thomas Gleixner
2019-11-07 1:11 ` Linus Torvalds
2019-11-07 7:44 ` Thomas Gleixner
2019-11-07 8:25 ` Ingo Molnar
2019-11-07 9:17 ` Willy Tarreau
2019-11-07 10:00 ` Thomas Gleixner
2019-11-07 10:13 ` Willy Tarreau
2019-11-07 10:19 ` hpa
2019-11-07 10:27 ` Willy Tarreau
2019-11-07 10:50 ` hpa
2019-11-07 12:56 ` Willy Tarreau
2019-11-07 16:45 ` Eric W. Biederman
2019-11-07 16:53 ` Linus Torvalds
2019-11-07 16:57 ` Willy Tarreau
2019-11-10 17:17 ` Andy Lutomirski
2019-11-07 7:37 ` Ingo Molnar [this message]
2019-11-07 7:45 ` Thomas Gleixner
2019-11-07 8:16 ` Ingo Molnar
2019-11-07 18:02 ` Thomas Gleixner
2019-11-07 19:24 ` Brian Gerst
2019-11-07 19:54 ` Linus Torvalds
2019-11-07 21:00 ` Brian Gerst
2019-11-07 21:32 ` Thomas Gleixner
2019-11-07 23:20 ` hpa
2019-11-07 21:44 ` Linus Torvalds
2019-11-08 1:12 ` H. Peter Anvin
2019-11-08 2:12 ` Brian Gerst
2019-11-10 17:21 ` Andy Lutomirski
2019-11-06 19:35 ` [patch 6/9] x86/iopl: Fixup misleading comment Thomas Gleixner
2019-11-06 19:35 ` [patch 7/9] x86/iopl: Restrict iopl() permission scope Thomas Gleixner
2019-11-07 9:09 ` Peter Zijlstra
2019-11-10 17:26 ` Andy Lutomirski
2019-11-10 20:31 ` Thomas Gleixner
2019-11-10 21:05 ` Andy Lutomirski
2019-11-10 21:21 ` Thomas Gleixner
2019-11-06 19:35 ` [patch 8/9] x86/iopl: Remove legacy IOPL option Thomas Gleixner
2019-11-07 6:11 ` Jürgen Groß
2019-11-07 6:26 ` hpa
2019-11-07 16:44 ` Stephen Hemminger
2019-11-07 9:13 ` Peter Zijlstra
2019-11-06 19:35 ` [patch 9/9] selftests/x86/iopl: Verify that CLI/STI result in #GP Thomas Gleixner
2019-11-07 7:28 ` [patch] x86/iopl: Remove unused local variable, update comments in ksys_ioperm() Ingo Molnar
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