From b7ceaec112aa35aa287325754d8c52b8304892cd Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Wed, 22 Feb 2017 07:36:16 -0800 Subject: x86/asm: Tidy up TSS limit code MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In an earlier version of the patch ("x86/kvm/vmx: Defer TR reload after VM exit") that introduced TSS limit validity tracking, I confused which helper was which. On reflection, the names I chose sucked. Rename the helpers to make it more obvious what's going on and add some comments. While I'm at it, clear __tss_limit_invalid when force-reloading as well as when contitionally reloading, since any TR reload fixes the limit. Signed-off-by: Andy Lutomirski Signed-off-by: Radim Krčmář --- arch/x86/kernel/ioport.c | 8 +++++++- arch/x86/kernel/process.c | 6 +++--- 2 files changed, 10 insertions(+), 4 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c index b01bc8517450..875d3d25dd6a 100644 --- a/arch/x86/kernel/ioport.c +++ b/arch/x86/kernel/ioport.c @@ -47,8 +47,14 @@ asmlinkage long sys_ioperm(unsigned long from, unsigned long num, int turn_on) t->io_bitmap_ptr = bitmap; set_thread_flag(TIF_IO_BITMAP); + /* + * Now that we have an IO bitmap, we need our TSS limit to be + * correct. It's fine if we are preempted after doing this: + * with TIF_IO_BITMAP set, context switches will keep our TSS + * limit correct. + */ preempt_disable(); - refresh_TR(); + refresh_tss_limit(); preempt_enable(); } diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 7780efa635b9..0b302591b51f 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -65,8 +65,8 @@ __visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss) = { }; EXPORT_PER_CPU_SYMBOL(cpu_tss); -DEFINE_PER_CPU(bool, need_tr_refresh); -EXPORT_PER_CPU_SYMBOL_GPL(need_tr_refresh); +DEFINE_PER_CPU(bool, __tss_limit_invalid); +EXPORT_PER_CPU_SYMBOL_GPL(__tss_limit_invalid); /* * this gets called so that we can store lazy state into memory and copy the @@ -218,7 +218,7 @@ void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p, * Make sure that the TSS limit is correct for the CPU * to notice the IO bitmap. */ - refresh_TR(); + refresh_tss_limit(); } else if (test_tsk_thread_flag(prev_p, TIF_IO_BITMAP)) { /* * Clear any possible leftover bits: -- cgit v1.2.3