Re: [PATCH v3 3/4] KVM: arm64: Align the VMID allocation with the arm64 ASID one

[kernel test robot <lkp@intel.com>]

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Hi Shameer,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on kvmarm/next]
[also build test WARNING on arm64/for-next/core arm/for-next soc/for-next rockchip/for-next shawnguo/for-next clk/clk-next v5.14-rc3 next-20210728]
[cannot apply to xlnx/master keystone/next linux-rpi/for-rpi-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Shameer-Kolothum/kvm-arm-New-VMID-allocator-based-on-asid/20210729-184607
base:   https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git next
config: arm64-allyesconfig (attached as .config)
compiler: aarch64-linux-gcc (GCC) 10.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/3ffbfe2e26ad324870b87a46b930a9a4c0a8faa1
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Shameer-Kolothum/kvm-arm-New-VMID-allocator-based-on-asid/20210729-184607
        git checkout 3ffbfe2e26ad324870b87a46b930a9a4c0a8faa1
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.3.0 make.cross ARCH=arm64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   arch/arm64/kvm/vmid.c: In function 'kvm_arm_vmid_update':
>> arch/arm64/kvm/vmid.c:122:15: warning: variable 'cpu' set but not used [-Wunused-but-set-variable]
     122 |  unsigned int cpu;
         |               ^~~


vim +/cpu +122 arch/arm64/kvm/vmid.c

0537d0e3bea2fa Shameer Kolothum 2021-07-29  118  
0537d0e3bea2fa Shameer Kolothum 2021-07-29  119  void kvm_arm_vmid_update(struct kvm_vmid *kvm_vmid)
0537d0e3bea2fa Shameer Kolothum 2021-07-29  120  {
0537d0e3bea2fa Shameer Kolothum 2021-07-29  121  	unsigned long flags;
0537d0e3bea2fa Shameer Kolothum 2021-07-29 @122  	unsigned int cpu;
0537d0e3bea2fa Shameer Kolothum 2021-07-29  123  	u64 vmid, old_active_vmid;
0537d0e3bea2fa Shameer Kolothum 2021-07-29  124  
0537d0e3bea2fa Shameer Kolothum 2021-07-29  125  	vmid = atomic64_read(&kvm_vmid->id);
0537d0e3bea2fa Shameer Kolothum 2021-07-29  126  
0537d0e3bea2fa Shameer Kolothum 2021-07-29  127  	/*
0537d0e3bea2fa Shameer Kolothum 2021-07-29  128  	 * Please refer comments in check_and_switch_context() in
0537d0e3bea2fa Shameer Kolothum 2021-07-29  129  	 * arch/arm64/mm/context.c.
0537d0e3bea2fa Shameer Kolothum 2021-07-29  130  	 */
0537d0e3bea2fa Shameer Kolothum 2021-07-29  131  	old_active_vmid = atomic64_read(this_cpu_ptr(&active_vmids));
0537d0e3bea2fa Shameer Kolothum 2021-07-29  132  	if (old_active_vmid && vmid_gen_match(vmid) &&
0537d0e3bea2fa Shameer Kolothum 2021-07-29  133  	    atomic64_cmpxchg_relaxed(this_cpu_ptr(&active_vmids),
0537d0e3bea2fa Shameer Kolothum 2021-07-29  134  				     old_active_vmid, vmid))
0537d0e3bea2fa Shameer Kolothum 2021-07-29  135  		return;
0537d0e3bea2fa Shameer Kolothum 2021-07-29  136  
0537d0e3bea2fa Shameer Kolothum 2021-07-29  137  	raw_spin_lock_irqsave(&cpu_vmid_lock, flags);
0537d0e3bea2fa Shameer Kolothum 2021-07-29  138  
0537d0e3bea2fa Shameer Kolothum 2021-07-29  139  	/* Check that our VMID belongs to the current generation. */
0537d0e3bea2fa Shameer Kolothum 2021-07-29  140  	vmid = atomic64_read(&kvm_vmid->id);
0537d0e3bea2fa Shameer Kolothum 2021-07-29  141  	if (!vmid_gen_match(vmid)) {
0537d0e3bea2fa Shameer Kolothum 2021-07-29  142  		vmid = new_vmid(kvm_vmid);
0537d0e3bea2fa Shameer Kolothum 2021-07-29  143  		atomic64_set(&kvm_vmid->id, vmid);
0537d0e3bea2fa Shameer Kolothum 2021-07-29  144  	}
0537d0e3bea2fa Shameer Kolothum 2021-07-29  145  
0537d0e3bea2fa Shameer Kolothum 2021-07-29  146  	cpu = smp_processor_id();
0537d0e3bea2fa Shameer Kolothum 2021-07-29  147  
0537d0e3bea2fa Shameer Kolothum 2021-07-29  148  	atomic64_set(this_cpu_ptr(&active_vmids), vmid);
0537d0e3bea2fa Shameer Kolothum 2021-07-29  149  	raw_spin_unlock_irqrestore(&cpu_vmid_lock, flags);
0537d0e3bea2fa Shameer Kolothum 2021-07-29  150  }
0537d0e3bea2fa Shameer Kolothum 2021-07-29  151  

---
0-DAY CI Kernel Test Service, Intel Corporation
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