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| author | Andy Lutomirski <luto@kernel.org> | 2020-07-17 16:53:55 -0700 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-07-18 12:31:49 +0200 |
| commit | cadfad870154e14f745ec845708bc17d166065f2 (patch) | |
| tree | 879e0402ec50885291708e574e56830130f424fb /arch/x86/kernel/process.c | |
| parent | 81e96851ea32deb2c921c870eecabf335f598aeb (diff) | |
| download | linux-cadfad870154e14f745ec845708bc17d166065f2.tar.gz linux-cadfad870154e14f745ec845708bc17d166065f2.tar.bz2 linux-cadfad870154e14f745ec845708bc17d166065f2.zip | |
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: 22fe5b0439dd ("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
Diffstat (limited to 'arch/x86/kernel/process.c')
| -rw-r--r-- | arch/x86/kernel/process.c | 18 |
1 files changed, 2 insertions, 16 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index f362ce0d5ac0..fe67dbd76e51 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -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; } |