linux/arch/x86/include/asm/io_bitmap.h
Andy Lutomirski cadfad8701 x86/ioperm: Fix io bitmap invalidation on Xen PV
tss_invalidate_io_bitmap() wasn't wired up properly through the pvop
machinery, so the TSS and Xen's io bitmap would get out of sync
whenever disabling a valid io bitmap.

Add a new pvop for tss_invalidate_io_bitmap() to fix it.

This is XSA-329.

Fixes: 22fe5b0439 ("x86/ioperm: Move TSS bitmap update to exit to user work")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/d53075590e1f91c19f8af705059d3ff99424c020.1595030016.git.luto@kernel.org
2020-07-18 12:31:49 +02:00

53 lines
1.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_IOBITMAP_H
#define _ASM_X86_IOBITMAP_H
#include <linux/refcount.h>
#include <asm/processor.h>
struct io_bitmap {
u64 sequence;
refcount_t refcnt;
/* The maximum number of bytes to copy so all zero bits are covered */
unsigned int max;
unsigned long bitmap[IO_BITMAP_LONGS];
};
struct task_struct;
#ifdef CONFIG_X86_IOPL_IOPERM
void io_bitmap_share(struct task_struct *tsk);
void io_bitmap_exit(struct task_struct *tsk);
static inline void native_tss_invalidate_io_bitmap(void)
{
/*
* Invalidate the I/O bitmap by moving io_bitmap_base outside the
* TSS limit so any subsequent I/O access from user space will
* trigger a #GP.
*
* This is correct even when VMEXIT rewrites the TSS limit
* to 0x67 as the only requirement is that the base points
* outside the limit.
*/
this_cpu_write(cpu_tss_rw.x86_tss.io_bitmap_base,
IO_BITMAP_OFFSET_INVALID);
}
void native_tss_update_io_bitmap(void);
#ifdef CONFIG_PARAVIRT_XXL
#include <asm/paravirt.h>
#else
#define tss_update_io_bitmap native_tss_update_io_bitmap
#define tss_invalidate_io_bitmap native_tss_invalidate_io_bitmap
#endif
#else
static inline void io_bitmap_share(struct task_struct *tsk) { }
static inline void io_bitmap_exit(struct task_struct *tsk) { }
static inline void tss_update_io_bitmap(void) { }
#endif
#endif