Re: [PATCH v8 2/2] s390x: KVM: resetting the Topology-Change-Report

kernel test robot
2022-04-21T06:41:10Z

Hi Pierre,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on kvm/master]
[also build test WARNING on v5.18-rc3]
[cannot apply to kvms390/next mst-vhost/linux-next next-20220420]
[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/intel-lab-lkp/linux/commits/Pierre-Morel/s390x-KVM-CPU-Topology/20220420-194302
base: https://git.kernel.org/pub/scm/virt/kvm/kvm.git master
config: s390-randconfig-r044-20220420 (https://download.01.org/0day-ci/archive/20220420/202204202111.vLX6pMo0-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project bac6cd5bf85669e3376610cfc4c4f9ca015e7b9b)
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
# install s390 cross compiling tool for clang build
# apt-get install binutils-s390x-linux-gnu
# https://github.com/intel-lab-lkp/linux/commit/0bdeef651636ac2ef4918fb6e3230614e2fb3581
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Pierre-Morel/s390x-KVM-CPU-Topology/20220420-194302
git checkout 0bdeef651636ac2ef4918fb6e3230614e2fb3581
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash arch/s390/kvm/

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 >>):

In file included from arch/s390/kvm/kvm-s390.c:22:
In file included from include/linux/kvm_host.h:41:
In file included from include/linux/kvm_para.h:5:
In file included from include/uapi/linux/kvm_para.h:37:
In file included from arch/s390/include/asm/kvm_para.h:25:
In file included from arch/s390/include/asm/diag.h:12:
In file included from include/linux/if_ether.h:19:
In file included from include/linux/skbuff.h:31:
In file included from include/linux/dma-mapping.h:10:
In file included from include/linux/scatterlist.h:9:
In file included from arch/s390/include/asm/io.h:75:
include/asm-generic/io.h:464:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __raw_readb(PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:477:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
~~~~~~~~~~ ^
include/uapi/linux/byteorder/big_endian.h:37:59: note: expanded from macro '__le16_to_cpu'
#define __le16_to_cpu(x) __swab16((__force __u16)(__le16)(x))
^
include/uapi/linux/swab.h:102:54: note: expanded from macro '__swab16'
#define __swab16(x) (__u16)__builtin_bswap16((__u16)(x))
^
In file included from arch/s390/kvm/kvm-s390.c:22:
In file included from include/linux/kvm_host.h:41:
In file included from include/linux/kvm_para.h:5:
In file included from include/uapi/linux/kvm_para.h:37:
In file included from arch/s390/include/asm/kvm_para.h:25:
In file included from arch/s390/include/asm/diag.h:12:
In file included from include/linux/if_ether.h:19:
In file included from include/linux/skbuff.h:31:
In file included from include/linux/dma-mapping.h:10:
In file included from include/linux/scatterlist.h:9:
In file included from arch/s390/include/asm/io.h:75:
include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
~~~~~~~~~~ ^
include/uapi/linux/byteorder/big_endian.h:35:59: note: expanded from macro '__le32_to_cpu'
#define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
^
include/uapi/linux/swab.h:115:54: note: expanded from macro '__swab32'
#define __swab32(x) (__u32)__builtin_bswap32((__u32)(x))
^
In file included from arch/s390/kvm/kvm-s390.c:22:
In file included from include/linux/kvm_host.h:41:
In file included from include/linux/kvm_para.h:5:
In file included from include/uapi/linux/kvm_para.h:37:
In file included from arch/s390/include/asm/kvm_para.h:25:
In file included from arch/s390/include/asm/diag.h:12:
In file included from include/linux/if_ether.h:19:
In file included from include/linux/skbuff.h:31:
In file included from include/linux/dma-mapping.h:10:
In file included from include/linux/scatterlist.h:9:
In file included from arch/s390/include/asm/io.h:75:
include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writeb(value, PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:511:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:521:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:609:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
readsb(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:617:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
readsw(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:625:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
readsl(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:634:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
writesb(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:643:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
writesw(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:652:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
writesl(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
>> arch/s390/kvm/kvm-s390.c:1773:6: warning: variable 'val' set but not used [-Wunused-but-set-variable]
int val;
^
13 warnings generated.

vim +/val +1773 arch/s390/kvm/kvm-s390.c

1758
1759 /**
1760 * kvm_s390_sca_clear_mtcr
1761 * @kvm: guest KVM description
1762 *
1763 * Is only relevant if the topology facility is present,
1764 * the caller should check KVM facility 11
1765 *
1766 * Updates the Multiprocessor Topology-Change-Report to signal
1767 * the guest with a topology change.
1768 */
1769 static int kvm_s390_sca_clear_mtcr(struct kvm *kvm)
1770 {
1771 struct bsca_block *sca = kvm->arch.sca;
1772 struct kvm_vcpu *vcpu;
> 1773 int val;
1774
1775 vcpu = kvm_s390_get_first_vcpu(kvm);
1776 if (!vcpu)
1777 return -ENODEV;
1778
1779 ipte_lock(vcpu);
1780 val = READ_ONCE(sca->utility);
1781 WRITE_ONCE(sca->utility, sca->utility & ~SCA_UTILITY_MTCR);
1782 ipte_unlock(vcpu);
1783
1784 return 0;
1785 }
1786

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