[PATCH 5/5] X86: Hyper-V: Consolidate the allocation of the hypercall input page

[kbuild test robot]

Hi Srinivasan,

I love your patch! Perhaps something to improve:

[auto build test WARNING on v4.17-rc2]
[also build test WARNING on next-20180426]
[cannot apply to tip/x86/core]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/kys-linuxonhyperv-com/X86-Hyper-V-APIC-enlightenments/20180427-114416
reproduce:
        # apt-get install sparse
        make ARCH=x86_64 allmodconfig
        make C=1 CF=-D__CHECK_ENDIAN__


sparse warnings: (new ones prefixed by >>)

>> arch/x86/hyperv/mmu.c:86:22: sparse: incorrect type in initializer (different address spaces) @@    expected void const [noderef] <asn:3>*__vpp_verify @@    got const [noderef] <asn:3>*__vpp_verify @@
   arch/x86/hyperv/mmu.c:86:22:    expected void const [noderef] <asn:3>*__vpp_verify
   arch/x86/hyperv/mmu.c:86:22:    got void [noderef] <asn:3>**<noident>
   arch/x86/hyperv/mmu.c:171:22: sparse: incorrect type in initializer (different address spaces) @@    expected void const [noderef] <asn:3>*__vpp_verify @@    got const [noderef] <asn:3>*__vpp_verify @@
   arch/x86/hyperv/mmu.c:171:22:    expected void const [noderef] <asn:3>*__vpp_verify
   arch/x86/hyperv/mmu.c:171:22:    got void [noderef] <asn:3>**<noident>

vim +86 arch/x86/hyperv/mmu.c

    65	
    66	static void hyperv_flush_tlb_others(const struct cpumask *cpus,
    67					    const struct flush_tlb_info *info)
    68	{
    69		int cpu, vcpu, gva_n, max_gvas;
    70		struct hv_flush_pcpu **flush_pcpu;
    71		struct hv_flush_pcpu *flush;
    72		u64 status = U64_MAX;
    73		unsigned long flags;
    74	
    75		trace_hyperv_mmu_flush_tlb_others(cpus, info);
    76	
    77		if (!hv_hypercall_pg)
    78			goto do_native;
    79	
    80		if (cpumask_empty(cpus))
    81			return;
    82	
    83		local_irq_save(flags);
    84	
    85		flush_pcpu = (struct hv_flush_pcpu **)
  > 86			     this_cpu_ptr(hyperv_pcpu_input_arg);
    87	
    88		flush = *flush_pcpu;
    89	
    90		if (unlikely(!flush)) {
    91			local_irq_restore(flags);
    92			goto do_native;
    93		}
    94	
    95		if (info->mm) {
    96			/*
    97			 * AddressSpace argument must match the CR3 with PCID bits
    98			 * stripped out.
    99			 */
   100			flush->address_space = virt_to_phys(info->mm->pgd);
   101			flush->address_space &= CR3_ADDR_MASK;
   102			flush->flags = 0;
   103		} else {
   104			flush->address_space = 0;
   105			flush->flags = HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES;
   106		}
   107	
   108		flush->processor_mask = 0;
   109		if (cpumask_equal(cpus, cpu_present_mask)) {
   110			flush->flags |= HV_FLUSH_ALL_PROCESSORS;
   111		} else {
   112			for_each_cpu(cpu, cpus) {
   113				vcpu = hv_cpu_number_to_vp_number(cpu);
   114				if (vcpu >= 64)
   115					goto do_native;
   116	
   117				__set_bit(vcpu, (unsigned long *)
   118					  &flush->processor_mask);
   119			}
   120		}
   121	
   122		/*
   123		 * We can flush not more than max_gvas with one hypercall. Flush the
   124		 * whole address space if we were asked to do more.
   125		 */
   126		max_gvas = (PAGE_SIZE - sizeof(*flush)) / sizeof(flush->gva_list[0]);
   127	
   128		if (info->end == TLB_FLUSH_ALL) {
   129			flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
   130			status = hv_do_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE,
   131						 flush, NULL);
   132		} else if (info->end &&
   133			   ((info->end - info->start)/HV_TLB_FLUSH_UNIT) > max_gvas) {
   134			status = hv_do_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE,
   135						 flush, NULL);
   136		} else {
   137			gva_n = fill_gva_list(flush->gva_list, 0,
   138					      info->start, info->end);
   139			status = hv_do_rep_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST,
   140						     gva_n, 0, flush, NULL);
   141		}
   142	
   143		local_irq_restore(flags);
   144	
   145		if (!(status & HV_HYPERCALL_RESULT_MASK))
   146			return;
   147	do_native:
   148		native_flush_tlb_others(cpus, info);
   149	}
   150	

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