mirror of
https://github.com/torvalds/linux.git
synced 2024-12-04 18:13:04 +00:00
cadfad8701
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
53 lines
1.3 KiB
C
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
|