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Message-ID: <202107271428.F5bbv8iJ-lkp@intel.com>
Date: Tue, 27 Jul 2021 14:46:37 +0800
From: kernel test robot <lkp@...el.com>
To: Huacai Chen <chenhc@...ote.com>
Cc: kbuild-all@...ts.01.org, linux-kernel@...r.kernel.org,
Paolo Bonzini <pbonzini@...hat.com>
Subject: arch/mips/kvm/vz.c:392:10: warning: variable 'freeze_time' set but
not used
Hi Huacai,
FYI, the error/warning still remains.
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: ff1176468d368232b684f75e82563369208bc371
commit: cf99c505cf7a5b6d3deee91e3571871f20320d31 MIPS: VZ: Only include loongson_regs.h for CPU_LOONGSON64
date: 12 months ago
config: mips-randconfig-r024-20210726 (attached as .config)
compiler: mips64-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://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=cf99c505cf7a5b6d3deee91e3571871f20320d31
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout cf99c505cf7a5b6d3deee91e3571871f20320d31
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.3.0 make.cross ARCH=mips
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@...el.com>
All warnings (new ones prefixed by >>):
arch/mips/kvm/vz.c: In function '_kvm_vz_restore_htimer':
>> arch/mips/kvm/vz.c:392:10: warning: variable 'freeze_time' set but not used [-Wunused-but-set-variable]
392 | ktime_t freeze_time;
| ^~~~~~~~~~~
vim +/freeze_time +392 arch/mips/kvm/vz.c
c992a4f6a9b0a3 James Hogan 2017-03-14 378
c992a4f6a9b0a3 James Hogan 2017-03-14 379 /**
f4474d50c7d483 James Hogan 2017-03-14 380 * _kvm_vz_restore_htimer() - Restore hard timer state.
f4474d50c7d483 James Hogan 2017-03-14 381 * @vcpu: Virtual CPU.
f4474d50c7d483 James Hogan 2017-03-14 382 * @compare: CP0_Compare register value, restored by caller.
f4474d50c7d483 James Hogan 2017-03-14 383 * @cause: CP0_Cause register to restore.
f4474d50c7d483 James Hogan 2017-03-14 384 *
f4474d50c7d483 James Hogan 2017-03-14 385 * Restore hard timer Guest.Count & Guest.Cause taking care to preserve the
f4474d50c7d483 James Hogan 2017-03-14 386 * value of Guest.CP0_Cause.TI while restoring Guest.CP0_Cause.
f4474d50c7d483 James Hogan 2017-03-14 387 */
f4474d50c7d483 James Hogan 2017-03-14 388 static void _kvm_vz_restore_htimer(struct kvm_vcpu *vcpu,
f4474d50c7d483 James Hogan 2017-03-14 389 u32 compare, u32 cause)
f4474d50c7d483 James Hogan 2017-03-14 390 {
f4474d50c7d483 James Hogan 2017-03-14 391 u32 start_count, after_count;
f4474d50c7d483 James Hogan 2017-03-14 @392 ktime_t freeze_time;
f4474d50c7d483 James Hogan 2017-03-14 393 unsigned long flags;
f4474d50c7d483 James Hogan 2017-03-14 394
f4474d50c7d483 James Hogan 2017-03-14 395 /*
f4474d50c7d483 James Hogan 2017-03-14 396 * Freeze the soft-timer and sync the guest CP0_Count with it. We do
f4474d50c7d483 James Hogan 2017-03-14 397 * this with interrupts disabled to avoid latency.
f4474d50c7d483 James Hogan 2017-03-14 398 */
f4474d50c7d483 James Hogan 2017-03-14 399 local_irq_save(flags);
f4474d50c7d483 James Hogan 2017-03-14 400 freeze_time = kvm_mips_freeze_hrtimer(vcpu, &start_count);
f4474d50c7d483 James Hogan 2017-03-14 401 write_c0_gtoffset(start_count - read_c0_count());
f4474d50c7d483 James Hogan 2017-03-14 402 local_irq_restore(flags);
f4474d50c7d483 James Hogan 2017-03-14 403
f4474d50c7d483 James Hogan 2017-03-14 404 /* restore guest CP0_Cause, as TI may already be set */
f4474d50c7d483 James Hogan 2017-03-14 405 back_to_back_c0_hazard();
f4474d50c7d483 James Hogan 2017-03-14 406 write_gc0_cause(cause);
f4474d50c7d483 James Hogan 2017-03-14 407
f4474d50c7d483 James Hogan 2017-03-14 408 /*
f4474d50c7d483 James Hogan 2017-03-14 409 * The above sequence isn't atomic and would result in lost timer
f4474d50c7d483 James Hogan 2017-03-14 410 * interrupts if we're not careful. Detect if a timer interrupt is due
f4474d50c7d483 James Hogan 2017-03-14 411 * and assert it.
f4474d50c7d483 James Hogan 2017-03-14 412 */
f4474d50c7d483 James Hogan 2017-03-14 413 back_to_back_c0_hazard();
f4474d50c7d483 James Hogan 2017-03-14 414 after_count = read_gc0_count();
f4474d50c7d483 James Hogan 2017-03-14 415 if (after_count - start_count > compare - start_count - 1)
f4474d50c7d483 James Hogan 2017-03-14 416 kvm_vz_queue_irq(vcpu, MIPS_EXC_INT_TIMER);
f4474d50c7d483 James Hogan 2017-03-14 417 }
f4474d50c7d483 James Hogan 2017-03-14 418
:::::: The code at line 392 was first introduced by commit
:::::: f4474d50c7d483dd4432d5b0891b0bb9ad0eefc9 KVM: MIPS/VZ: Support hardware guest timer
:::::: TO: James Hogan <james.hogan@...tec.com>
:::::: CC: James Hogan <james.hogan@...tec.com>
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
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