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Commit 9c6ff8bb authored by Suresh Siddha's avatar Suresh Siddha Committed by H. Peter Anvin
Browse files

lguest, x86: handle guest TS bit for lazy/non-lazy fpu host models 



Instead of using unlazy_fpu() check if user_has_fpu() and set/clear
the host TS bits so that the lguest works fine with both the
lazy/non-lazy FPU host models with minimal changes.

Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1345842782-24175-6-git-send-email-suresh.b.siddha@intel.com


Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent 841e3604

drivers/lguest/x86/core.c

+7 −3
Original line number Diff line number Diff line
@@ -203,8 +203,8 @@ void lguest_arch_run_guest(struct lg_cpu *cpu) 
	 * we set it now, so we can trap and pass that trap to the Guest if it

	 * uses the FPU.

	 */

	if (cpu->ts)

		unlazy_fpu(current);

	if (cpu->ts && user_has_fpu())

		stts();



	/*

	 * SYSENTER is an optimized way of doing system calls.  We can't allow
@@ -234,6 +234,10 @@ void lguest_arch_run_guest(struct lg_cpu *cpu) 
	 if (boot_cpu_has(X86_FEATURE_SEP))

		wrmsr(MSR_IA32_SYSENTER_CS, __KERNEL_CS, 0);



	/* Clear the host TS bit if it was set above. */

	if (cpu->ts && user_has_fpu())

		clts();



	/*

	 * If the Guest page faulted, then the cr2 register will tell us the

	 * bad virtual address.  We have to grab this now, because once we
@@ -249,7 +253,7 @@ void lguest_arch_run_guest(struct lg_cpu *cpu) 
	 * a different CPU. So all the critical stuff should be done

	 * before this.

	 */

	else if (cpu->regs->trapnum == 7)

	else if (cpu->regs->trapnum == 7 && !user_has_fpu())

		math_state_restore();

}