Messages in this thread | | | Subject | Re: [patch 1/2 v2] x86/cpu: Init AP exception handling from cpu_init_secondary() | From | Lai Jiangshan <> | Date | Tue, 11 May 2021 17:25:35 +0800 |
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On 2021/5/11 05:29, Thomas Gleixner wrote: > From: Borislav Petkov <bp@suse.de> > > SEV-ES guests require properly setup task register with which the TSS > descriptor in the GDT can be located so that the IST-type #VC exception > handler which they need to function properly, can be executed. > > This setup needs to happen before attempting to load microcode in > ucode_cpu_init() on secondary CPUs which can cause such #VC exceptions. > > Simplify the machinery by running that exception setup from a new function > cpu_init_secondary() and explicitly call cpu_init_exception_handling() for > the boot CPU before cpu_init(). The latter prepares for fixing and > simplifying the exception/IST setup on the boot CPU. > > There should be no functional changes resulting from this patch. > > [ tglx: Reworked it so cpu_init_exception_handling() stays seperate ] > > Signed-off-by: Borislav Petkov <bp@suse.de> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
For both patches:
Reviewed-by: Lai Jiangshan <laijs@linux.alibaba.com>
> --- > V2: Utilize cpu_init_secondary() - Lai > --- > arch/x86/include/asm/processor.h | 1 + > arch/x86/kernel/cpu/common.c | 24 +++++++++++------------- > arch/x86/kernel/smpboot.c | 3 +-- > arch/x86/kernel/traps.c | 4 +--- > 4 files changed, 14 insertions(+), 18 deletions(-) > > --- a/arch/x86/include/asm/processor.h > +++ b/arch/x86/include/asm/processor.h > @@ -663,6 +663,7 @@ extern void load_direct_gdt(int); > extern void load_fixmap_gdt(int); > extern void load_percpu_segment(int); > extern void cpu_init(void); > +extern void cpu_init_secondary(void); > extern void cpu_init_exception_handling(void); > extern void cr4_init(void); > > --- a/arch/x86/kernel/cpu/common.c > +++ b/arch/x86/kernel/cpu/common.c > @@ -1938,13 +1938,12 @@ void cpu_init_exception_handling(void) > > /* > * cpu_init() initializes state that is per-CPU. Some data is already > - * initialized (naturally) in the bootstrap process, such as the GDT > - * and IDT. We reload them nevertheless, this function acts as a > - * 'CPU state barrier', nothing should get across. > + * initialized (naturally) in the bootstrap process, such as the GDT. We > + * reload it nevertheless, this function acts as a 'CPU state barrier', > + * nothing should get across. > */ > void cpu_init(void) > { > - struct tss_struct *tss = this_cpu_ptr(&cpu_tss_rw); > struct task_struct *cur = current; > int cpu = raw_smp_processor_id(); > > @@ -1957,8 +1956,6 @@ void cpu_init(void) > early_cpu_to_node(cpu) != NUMA_NO_NODE) > set_numa_node(early_cpu_to_node(cpu)); > #endif > - setup_getcpu(cpu); > - > pr_debug("Initializing CPU#%d\n", cpu); > > if (IS_ENABLED(CONFIG_X86_64) || cpu_feature_enabled(X86_FEATURE_VME) || > @@ -1970,7 +1967,6 @@ void cpu_init(void) > * and set up the GDT descriptor: > */ > switch_to_new_gdt(cpu); > - load_current_idt(); > > if (IS_ENABLED(CONFIG_X86_64)) { > loadsegment(fs, 0); > @@ -1990,12 +1986,6 @@ void cpu_init(void) > initialize_tlbstate_and_flush(); > enter_lazy_tlb(&init_mm, cur); > > - /* Initialize the TSS. */ > - tss_setup_ist(tss); > - tss_setup_io_bitmap(tss); > - set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss); > - > - load_TR_desc(); > /* > * sp0 points to the entry trampoline stack regardless of what task > * is running. > @@ -2017,6 +2007,14 @@ void cpu_init(void) > load_fixmap_gdt(cpu); > } > > +#ifdef CONFIG_SMP > +void cpu_init_secondary(void) > +{ > + cpu_init_exception_handling(); > + cpu_init(); > +} > +#endif > + > /* > * The microcode loader calls this upon late microcode load to recheck features, > * only when microcode has been updated. Caller holds microcode_mutex and CPU > --- a/arch/x86/kernel/smpboot.c > +++ b/arch/x86/kernel/smpboot.c > @@ -232,8 +232,7 @@ static void notrace start_secondary(void > load_cr3(swapper_pg_dir); > __flush_tlb_all(); > #endif > - cpu_init_exception_handling(); > - cpu_init(); > + cpu_init_secondary(); > rcu_cpu_starting(raw_smp_processor_id()); > x86_cpuinit.early_percpu_clock_init(); > preempt_disable(); > --- a/arch/x86/kernel/traps.c > +++ b/arch/x86/kernel/traps.c > @@ -1162,9 +1162,7 @@ void __init trap_init(void) > > idt_setup_traps(); > > - /* > - * Should be a barrier for any external CPU state: > - */ > + cpu_init_exception_handling(); > cpu_init(); > > idt_setup_ist_traps(); >
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