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