xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

x86/ioperm: Fix io bitmap invalidation on Xen PV

Browse Source 
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
This commit is contained in:
Andy Lutomirski
2020-07-17 16:53:55 -07:00
committed by Thomas Gleixner
parent 81e96851ea
commit cadfad8701
6 changed files with 38 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
arch/x86/kernel/process.c
View File

@@ -322,20 +322,6 @@ void arch_setup_new_exec(void)
}
#ifdef CONFIG_X86_IOPL_IOPERM
static inline void tss_invalidate_io_bitmap(struct tss_struct *tss)
{
/*
* 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.
*/
tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET_INVALID;
}
static inline void switch_to_bitmap(unsigned long tifp)
{
/*
@@ -346,7 +332,7 @@ static inline void switch_to_bitmap(unsigned long tifp)
* user mode.
*/
if (tifp & _TIF_IO_BITMAP)
tss_invalidate_io_bitmap(this_cpu_ptr(&cpu_tss_rw));
tss_invalidate_io_bitmap();
}
static void tss_copy_io_bitmap(struct tss_struct *tss, struct io_bitmap *iobm)
@@ -380,7 +366,7 @@ void native_tss_update_io_bitmap(void)
u16 *base = &tss->x86_tss.io_bitmap_base;
if (!test_thread_flag(TIF_IO_BITMAP)) {
tss_invalidate_io_bitmap(tss);
native_tss_invalidate_io_bitmap();
return;
}