From 9c6ff8bbb69a4e7b47ac40bfa44509296e89c5c0 Mon Sep 17 00:00:00 2001 From: Suresh Siddha <suresh.b.siddha@intel.com> Date: Fri, 24 Aug 2012 14:13:01 -0700 Subject: [PATCH] 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: Suresh 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: H. Peter Anvin <hpa@linux.intel.com> --- drivers/lguest/x86/core.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/lguest/x86/core.c b/drivers/lguest/x86/core.c index 39809035320a8..4af12e1844d5d 100644 --- a/drivers/lguest/x86/core.c +++ b/drivers/lguest/x86/core.c @@ -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(); } -- GitLab