x86/ioperm: Save an indentation level in tss_update_io_bitmap() (7b0b8cfd) · Commits · 戴 / test

arch/x86/kernel/process.c

+26 −26

Original line number	Diff line number	Diff line
		@@ -377,19 +377,22 @@ static void tss_copy_io_bitmap(struct tss_struct tss, struct io_bitmap iobm)
		void tss_update_io_bitmap(void)
		{
		struct tss_struct *tss = this_cpu_ptr(&cpu_tss_rw);
		struct thread_struct *t = &current->thread;
		u16 *base = &tss->x86_tss.io_bitmap_base;

		if (test_thread_flag(TIF_IO_BITMAP)) {
		struct thread_struct *t = &current->thread;
		if (!test_thread_flag(TIF_IO_BITMAP)) {
		tss_invalidate_io_bitmap(tss);
		return;
		}

		if (IS_ENABLED(CONFIG_X86_IOPL_IOPERM) && t->iopl_emul == 3) {
		*base = IO_BITMAP_OFFSET_VALID_ALL;
		} else {
		struct io_bitmap *iobm = t->io_bitmap;

		/*
		* Only copy bitmap data when the sequence number
		* differs. The update time is accounted to the
		* incoming task.
		* Only copy bitmap data when the sequence number differs. The
		* update time is accounted to the incoming task.
		*/
		if (tss->io_bitmap.prev_sequence != iobm->sequence)
		tss_copy_io_bitmap(tss, iobm);
		@@ -397,17 +400,14 @@ void tss_update_io_bitmap(void)
		/* Enable the bitmap */
		*base = IO_BITMAP_OFFSET_VALID_MAP;
		}

		/*
		* Make sure that the TSS limit is covering the io bitmap.
		* It might have been cut down by a VMEXIT to 0x67 which
		* would cause a subsequent I/O access from user space to
		* trigger a #GP because tbe bitmap is outside the TSS
		* limit.
		* Make sure that the TSS limit is covering the IO bitmap. It might have
		* been cut down by a VMEXIT to 0x67 which would cause a subsequent I/O
		* access from user space to trigger a #GP because tbe bitmap is outside
		* the TSS limit.
		*/
		refresh_tss_limit();
		} else {
		tss_invalidate_io_bitmap(tss);
		}
		}
		#else /* CONFIG_X86_IOPL_IOPERM */
		static inline void switch_to_bitmap(unsigned long tifp) { }

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