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From: Ingo Molnar <mingo@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
	x86@kernel.org, Linus Torvalds <torvalds@linuxfoundation.org>,
	Andy Lutomirski <luto@kernel.org>,
	Stephen Hemminger <stephen@networkplumber.org>,
	Willy Tarreau <w@1wt.eu>, Juergen Gross <jgross@suse.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>
Subject: [PATCH] x86/iopl: Harmonize 'struct io_bitmap' and 'struct x86_io_bitmap' nomenclature
Date: Tue, 12 Nov 2019 08:59:42 +0100
Message-ID: <20191112075942.GF100264@gmail.com> (raw)
In-Reply-To: <20191112074052.GD100264@gmail.com>


* Ingo Molnar <mingo@kernel.org> wrote:

> How about the patch below?
> 
> It reorganizes all those fields into a new container structure, 'struct 
> x86_io_bitmap', adds it as tss.io_bitmap, and uses the prefix to shorten 
> and organize the names of the fields:
> 
>    tss.last_bitmap         =>  tss.io_bitmap.last_bitmap
>    tss.last_sequence       =>  tss.io_bitmap.last_sequence
>    tss.io_bitmap_prev_max  =>  tss.io_bitmap.prev_max
>    tss.io_bitmap_bytes     =>  tss.io_bitmap.map_bytes
>    tss.io_bitmap_all       =>  tss.io_bitmap.map_all
> 
> This makes it far more readable, and the local variable references as 
> short and tidy:
> 
>    iobm->last_bitmap
>    iobm->last_sequence
>    iobm->prev_max
>    iobm->map_bytes
>    iobm->map_all
> 
> Only build tested.

On top of this we can now do the slight reorganization of field names 
below.

    io_bitmap.io_bitmap_max => bytes_max
    x86_io_bitmap.prev_max => bytes_max


The point is to harmonize the fields in 'struct io_bitmap' with 'struct 
x86_io_bitmap':

    io_bitmap.map_bytes      io_bitmap.bytes_max
         iobm.map_bytes           iobm.bytes_max


which makes following segments of code really tidy:

  memcpy(tss->io_bitmap.map_bytes, iobm->map_bytes,
               max(tss->io_bitmap.bytes_max, iobm->bytes_max));

The other point is to remove the 'prev' notion from the TSS data field - 
there's very little "previous" about this - we have this bitmap loaded 
right now.

Also note the cleanup of the bits/bytes union:

   iobm->bits           =>   iobm->map_bits
   iobm->bitmap_bytes   =>   iobm->map_bytes

Only build tested, but 100% perfect, guaranteed.

Thanks,

	Ingo

---
 arch/x86/include/asm/iobitmap.h  |  6 +++---
 arch/x86/include/asm/processor.h |  2 +-
 arch/x86/kernel/cpu/common.c     |  2 +-
 arch/x86/kernel/ioport.c         | 10 +++++-----
 arch/x86/kernel/process.c        |  6 +++---
 arch/x86/kernel/ptrace.c         |  4 ++--
 6 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/arch/x86/include/asm/iobitmap.h b/arch/x86/include/asm/iobitmap.h
index a075f0c55fb3..faba42c7d3de 100644
--- a/arch/x86/include/asm/iobitmap.h
+++ b/arch/x86/include/asm/iobitmap.h
@@ -8,10 +8,10 @@
 struct io_bitmap {
 	u64			sequence;
 	refcount_t		refcnt;
-	unsigned int		io_bitmap_max;
+	unsigned int		bytes_max;
 	union {
-		unsigned long	bits[IO_BITMAP_LONGS];
-		unsigned char	bitmap_bytes[IO_BITMAP_BYTES];
+		unsigned long	map_bits[IO_BITMAP_LONGS];
+		unsigned char	map_bytes[IO_BITMAP_BYTES];
 	};
 };
 
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 4358ae63c252..d1f2c1eb14e9 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -381,7 +381,7 @@ struct x86_io_bitmap
 	 * outside of the TSS limit. So for sane tasks there is no need to
 	 * actually touch the io_bitmap at all.
 	 */
-	unsigned int		prev_max;
+	unsigned int		bytes_max;
 
 	/*
 	 * The extra 1 is there because the CPU will access an
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index eea0e3170de4..a35a557429e7 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1862,7 +1862,7 @@ void cpu_init(void)
 	tss_setup_ist(tss);
 	tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET_INVALID;
 	tss->io_bitmap.last_bitmap = NULL;
-	tss->io_bitmap.prev_max = 0;
+	tss->io_bitmap.bytes_max = 0;
 	memset(tss->io_bitmap.map_bytes, 0xff, sizeof(tss->io_bitmap.map_bytes));
 	set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss);
 
diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c
index ee37a1c25ecc..203f82383bf6 100644
--- a/arch/x86/kernel/ioport.c
+++ b/arch/x86/kernel/ioport.c
@@ -86,7 +86,7 @@ long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
 		if (!iobm)
 			return -ENOMEM;
 
-		memset(iobm->bits, 0xff, sizeof(iobm->bits));
+		memset(iobm->map_bits, 0xff, sizeof(iobm->map_bits));
 		refcount_set(&iobm->refcnt, 1);
 	}
 
@@ -112,9 +112,9 @@ long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
 	 * exit to user mode. So this needs no protection.
 	 */
 	if (turn_on)
-		bitmap_clear(iobm->bits, from, num);
+		bitmap_clear(iobm->map_bits, from, num);
 	else
-		bitmap_set(iobm->bits, from, num);
+		bitmap_set(iobm->map_bits, from, num);
 
 	/*
 	 * Search for a (possibly new) maximum. This is simple and stupid,
@@ -122,7 +122,7 @@ long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
 	 */
 	max_long = UINT_MAX;
 	for (i = 0; i < IO_BITMAP_LONGS; i++) {
-		if (iobm->bits[i] != ~0UL)
+		if (iobm->map_bits[i] != ~0UL)
 			max_long = i;
 	}
 
@@ -132,7 +132,7 @@ long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
 		return 0;
 	}
 
-	iobm->io_bitmap_max = (max_long + 1) * sizeof(unsigned long);
+	iobm->bytes_max = (max_long + 1) * sizeof(unsigned long);
 
 	/* Increment the sequence number to force a TSS update */
 	iobm->sequence = atomic64_add_return(1, &io_bitmap_sequence);
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 8179f3ee6a55..c4e76a540b51 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -350,14 +350,14 @@ static void tss_copy_io_bitmap(struct tss_struct *tss, struct io_bitmap *iobm)
 	 * permitted, then the copy needs to cover those as well so they
 	 * get turned off.
 	 */
-	memcpy(tss->io_bitmap.map_bytes, iobm->bitmap_bytes,
-	       max(tss->io_bitmap.prev_max, iobm->io_bitmap_max));
+	memcpy(tss->io_bitmap.map_bytes, iobm->map_bytes,
+	       max(tss->io_bitmap.bytes_max, iobm->bytes_max));
 
 	/*
 	 * Store the new max and the sequence number of this bitmap
 	 * and a pointer to the bitmap itself.
 	 */
-	tss->io_bitmap.prev_max = iobm->io_bitmap_max;
+	tss->io_bitmap.bytes_max = iobm->bytes_max;
 	tss->io_bitmap.last_sequence = iobm->sequence;
 	tss->io_bitmap.last_bitmap = iobm;
 }
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 6baa5a1a9f1c..f27c322f1c93 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -700,7 +700,7 @@ static int ioperm_active(struct task_struct *target,
 {
 	struct io_bitmap *iobm = target->thread.io_bitmap;
 
-	return iobm ? DIV_ROUND_UP(iobm->io_bitmap_max, regset->size) : 0;
+	return iobm ? DIV_ROUND_UP(iobm->bytes_max, regset->size) : 0;
 }
 
 static int ioperm_get(struct task_struct *target,
@@ -714,7 +714,7 @@ static int ioperm_get(struct task_struct *target,
 		return -ENXIO;
 
 	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-				   iobm->bitmap_bytes, 0, IO_BITMAP_BYTES);
+				   iobm->map_bytes, 0, IO_BITMAP_BYTES);
 }
 
 /*

  reply index

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-11 22:03 [patch V2 00/16] x86/iopl: Prevent user space from using CLI/STI with iopl(3) Thomas Gleixner
2019-11-11 22:03 ` [patch V2 01/16] x86/ptrace: Prevent truncation of bitmap size Thomas Gleixner
2019-11-12 15:34   ` Andy Lutomirski
2019-11-11 22:03 ` [patch V2 02/16] x86/process: Unify copy_thread_tls() Thomas Gleixner
2019-11-11 22:03 ` [patch V2 03/16] x86/cpu: Unify cpu_init() Thomas Gleixner
2019-11-11 22:03 ` [patch V2 04/16] x86/tss: Fix and move VMX BUILD_BUG_ON() Thomas Gleixner
2019-11-11 22:44   ` Paolo Bonzini
2019-11-12 15:37   ` Andy Lutomirski
2019-11-11 22:03 ` [patch V2 05/16] x86/iopl: Cleanup include maze Thomas Gleixner
2019-11-12 15:37   ` Andy Lutomirski
2019-11-11 22:03 ` [patch V2 06/16] x86/io: Speedup schedule out of I/O bitmap user Thomas Gleixner
2019-11-12 16:00   ` Andy Lutomirski
2019-11-12 17:08     ` Thomas Gleixner
2019-11-11 22:03 ` [patch V2 07/16] x86/ioperm: Move iobitmap data into a struct Thomas Gleixner
2019-11-12 16:02   ` Andy Lutomirski
2019-11-12 17:08     ` Thomas Gleixner
2019-11-11 22:03 ` [patch V2 08/16] x86/ioperm: Add bitmap sequence number Thomas Gleixner
2019-11-12  9:22   ` Peter Zijlstra
2019-11-12  9:55     ` [patch V2 08/16] x86/ioperm: Add bitmap sequence numberc Thomas Gleixner
2019-11-12 16:08   ` [patch V2 08/16] x86/ioperm: Add bitmap sequence number Andy Lutomirski
2019-11-12 17:10     ` Thomas Gleixner
2019-11-11 22:03 ` [patch V2 09/16] x86/ioperm: Move TSS bitmap update to exit to user work Thomas Gleixner
2019-11-12 16:16   ` Andy Lutomirski
2019-11-12 17:20     ` Thomas Gleixner
2019-11-12 17:41       ` Andy Lutomirski
2019-11-12 17:46         ` Linus Torvalds
2019-11-13  8:30           ` Peter Zijlstra
2019-11-11 22:03 ` [patch V2 10/16] x86/ioperm: Remove bitmap if all permissions dropped Thomas Gleixner
2019-11-12 17:43   ` Andy Lutomirski
2019-11-11 22:03 ` [patch V2 11/16] x86/ioperm: Share I/O bitmap if identical Thomas Gleixner
2019-11-12  7:14   ` Ingo Molnar
2019-11-12  7:17     ` Thomas Gleixner
2019-11-12  7:52       ` Ingo Molnar
2019-11-12  9:15   ` Peter Zijlstra
2019-11-12  9:51     ` Thomas Gleixner
2019-11-14 11:02     ` David Laight
2019-11-14 12:39       ` Thomas Gleixner
2019-11-14 13:09       ` Peter Zijlstra
2019-11-14 13:22         ` David Laight
2019-11-12 18:12   ` Andy Lutomirski
2019-11-11 22:03 ` [patch V2 12/16] selftests/x86/ioperm: Extend testing so the shared bitmap is exercised Thomas Gleixner
2019-11-11 22:03 ` [patch V2 13/16] x86/iopl: Fixup misleading comment Thomas Gleixner
2019-11-12 18:14   ` Andy Lutomirski
2019-11-11 22:03 ` [patch V2 14/16] x86/iopl: Restrict iopl() permission scope Thomas Gleixner
2019-11-11 23:03   ` Thomas Gleixner
2019-11-12  6:32     ` Ingo Molnar
2019-11-12  8:42   ` Ingo Molnar
2019-11-12 10:07     ` Thomas Gleixner
2019-11-12 18:35   ` Andy Lutomirski
2019-11-11 22:03 ` [patch V2 15/16] x86/iopl: Remove legacy IOPL option Thomas Gleixner
2019-11-12 18:37   ` Andy Lutomirski
2019-11-12 19:40     ` Thomas Gleixner
2019-11-11 22:03 ` [patch V2 16/16] selftests/x86/iopl: Extend test to cover IOPL emulation Thomas Gleixner
2019-11-12  7:40 ` [PATCH] x86/iopl: Factor out IO-bitmap related TSS fields into 'struct x86_io_bitmap' Ingo Molnar
2019-11-12  7:59   ` Ingo Molnar [this message]
2019-11-12  8:11   ` [PATCH] x86/iopl: Clear up the role of the two bitmap copying fields Ingo Molnar
2019-11-12  8:15   ` [PATCH] x86/iopl: Rename <asm/iobitmap.h> to <asm/io_bitmap.h> Ingo Molnar

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