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authorSuresh Siddha <suresh.b.siddha@intel.com>2012-08-24 14:13:01 -0700
committerH. Peter Anvin <hpa@linux.intel.com>2012-09-18 15:52:09 -0700
commit9c6ff8bbb69a4e7b47ac40bfa44509296e89c5c0 (patch)
treeae4e563e6afd275f4528877ac3ff884ccb62b243 /drivers/lguest
parent841e3604d35aa70d399146abdc526d8c89a2c2f5 (diff)
downloadkernel-9c6ff8bbb69a4e7b47ac40bfa44509296e89c5c0.tar.gz
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>
Diffstat (limited to 'drivers/lguest')
-rw-r--r--drivers/lguest/x86/core.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/lguest/x86/core.c b/drivers/lguest/x86/core.c
index 39809035320a..4af12e1844d5 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();
}