diff options
| author | Andy Lutomirski <luto@kernel.org> | 2020-07-18 02:53:55 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-07-18 13:31:49 +0300 |
| commit | cadfad870154e14f745ec845708bc17d166065f2 (patch) | |
| tree | 879e0402ec50885291708e574e56830130f424fb /arch/x86/include/asm/io_bitmap.h | |
| parent | 81e96851ea32deb2c921c870eecabf335f598aeb (diff) | |
| download | linux-cadfad870154e14f745ec845708bc17d166065f2.tar.xz | |
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/include/asm/io_bitmap.h')
| -rw-r--r-- | arch/x86/include/asm/io_bitmap.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/x86/include/asm/io_bitmap.h b/arch/x86/include/asm/io_bitmap.h index ac1a99ffbd8d..7f080f5c7def 100644 --- a/arch/x86/include/asm/io_bitmap.h +++ b/arch/x86/include/asm/io_bitmap.h @@ -19,12 +19,28 @@ struct task_struct; 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 |