On native hardware, IRET and POPF will correctly restore the IOPL bits. This was left over from when the SYSEXIT path did not restore the user flags with POPF.
Signed-off-by: Brian Gerst <[email protected]> --- arch/x86/include/asm/processor.h | 21 +-------------------- arch/x86/kernel/paravirt.c | 2 +- 2 files changed, 2 insertions(+), 21 deletions(-) diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 3cada99..06c4795 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -482,25 +482,6 @@ struct thread_struct { */ #define TS_COMPAT 0x0002 /* 32bit syscall active (64BIT)*/ -/* - * Set IOPL bits in EFLAGS from given mask - */ -static inline void native_set_iopl_mask(unsigned mask) -{ -#ifdef CONFIG_X86_32 - unsigned int reg; - - asm volatile ("pushfl;" - "popl %0;" - "andl %1, %0;" - "orl %2, %0;" - "pushl %0;" - "popfl" - : "=&r" (reg) - : "i" (~X86_EFLAGS_IOPL), "r" (mask)); -#endif -} - static inline void native_load_sp0(struct tss_struct *tss, struct thread_struct *thread) { @@ -542,7 +523,7 @@ static inline void load_sp0(struct tss_struct *tss, native_load_sp0(tss, thread); } -#define set_iopl_mask native_set_iopl_mask +static inline void set_iopl_mask(unsigned mask) { } #endif /* CONFIG_PARAVIRT */ /* Free all resources held by a thread. */ diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c index 3586996..1d50eb5 100644 --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -367,7 +367,7 @@ __visible struct pv_cpu_ops pv_cpu_ops = { .iret = native_iret, .swapgs = native_swapgs, - .set_iopl_mask = native_set_iopl_mask, + .set_iopl_mask = paravirt_nop, .io_delay = native_io_delay, .start_context_switch = paravirt_nop, -- 2.9.4
