Re: [PATCH 6/9] kvm: s390: Add configuration dump functionality

kernel test robot
2022-02-23T18:14:46Z

Hi Janosch,

I love your patch! Perhaps something to improve:

[auto build test WARNING on kvms390/next]
[also build test WARNING on next-20220222]
[cannot apply to kvm/master s390/features v5.17-rc5]
[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/Janosch-Frank/kvm-s390-Add-PV-dump-support/20220223-172213
base: https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux.git next
config: s390-randconfig-r044-20220223 (https://download.01.org/0day-ci/archive/20220224/202202240208.nprfvRMA-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project d271fc04d5b97b12e6b797c6067d3c96a8d7470e)
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/0day-ci/linux/commit/63a2029ece7e8fee92aa5ad277e2cbd8b13b7e6b
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Janosch-Frank/kvm-s390-Add-PV-dump-support/20220223-172213
git checkout 63a2029ece7e8fee92aa5ad277e2cbd8b13b7e6b
# save the config file to linux build tree
mkdir build_dir
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/pv.c:9:
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/pv.c:9:
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/pv.c:9:
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/pv.c:369:2: warning: variable 'cc' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
if (!buff_kvm)
^~~~~~~~~~~~~~
include/linux/compiler.h:56:28: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:58:30: note: expanded from macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/s390/kvm/pv.c:419:9: note: uninitialized use occurs here
return cc ? -EINVAL : 0;
^~
arch/s390/kvm/pv.c:369:2: note: remove the 'if' if its condition is always false
if (!buff_kvm)
^~~~~~~~~~~~~~
include/linux/compiler.h:56:23: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^
arch/s390/kvm/pv.c:357:2: warning: variable 'cc' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
if (!buff_user_len ||
^~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:56:28: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:58:30: note: expanded from macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/s390/kvm/pv.c:419:9: note: uninitialized use occurs here
return cc ? -EINVAL : 0;
^~
arch/s390/kvm/pv.c:357:2: note: remove the 'if' if its condition is always false
if (!buff_user_len ||
^~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:56:23: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^
arch/s390/kvm/pv.c:348:2: warning: variable 'cc' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
if (*gaddr & ~HPAGE_MASK)
^~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:56:28: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:58:30: note: expanded from macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/s390/kvm/pv.c:419:9: note: uninitialized use occurs here
return cc ? -EINVAL : 0;
^~
arch/s390/kvm/pv.c:348:2: note: remove the 'if' if its condition is always false
if (*gaddr & ~HPAGE_MASK)
^~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:56:23: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^
arch/s390/kvm/pv.c:344:8: note: initialize the variable 'cc' to silence this warning
int cc, ret;
^
= 0
15 warnings generated.

vim +369 arch/s390/kvm/pv.c

309
310 /*
311 * kvm_s390_pv_dump_stor_state
312 *
313 * @kvm: pointer to the guest's KVM struct
314 * @buff_user: Userspace pointer where we will write the results to
315 * @gaddr: Starting absolute guest address for which the storage state
316 * is requested. This value will be updated with the last
317 * address for which data was written when returning to
318 * userspace.
319 * @buff_user_len: Length of the buff_user buffer
320 * @rc: Pointer to where the uvcb return code is stored
321 * @rrc: Pointer to where the uvcb return reason code is stored
322 *
323 * Return:
324 * 0 on success
325 * -ENOMEM if allocating the cache fails
326 * -EINVAL if gaddr is not aligned to 1MB
327 * -EINVAL if buff_user_len is not aligned to uv_info.conf_dump_storage_state_len
328 * -EINVAL if the UV call fails, rc and rrc will be set in this case
329 * -EFAULT if copying the result to buff_user failed
330 */
331 int kvm_s390_pv_dump_stor_state(struct kvm *kvm, void __user *buff_user,
332 u64 *gaddr, u64 buff_user_len, u16 *rc, u16 *rrc)
333 {
334 struct uv_cb_dump_stor_state uvcb = {
335 .header.cmd = UVC_CMD_DUMP_CONF_STOR_STATE,
336 .header.len = sizeof(uvcb),
337 .config_handle = kvm->arch.pv.handle,
338 .gaddr = *gaddr,
339 .dump_area_origin = 0,
340 };
341 size_t buff_kvm_size;
342 size_t size_done = 0;
343 u8 *buff_kvm = NULL;
344 int cc, ret;
345
346 ret = -EINVAL;
347 /* UV call processes 1MB guest storage chunks at a time */
348 if (*gaddr & ~HPAGE_MASK)
349 goto out;
350
351 /*
352 * We provide the storage state for 1MB chunks of guest
353 * storage. The buffer will need to be aligned to
354 * conf_dump_storage_state_len so we don't end on a partial
355 * chunk.
356 */
357 if (!buff_user_len ||
358 buff_user_len & (uv_info.conf_dump_storage_state_len - 1))
359 goto out;
360
361 /*
362 * Allocate a buffer from which we will later copy to the user process.
363 *
364 * We don't want userspace to dictate our buffer size so we limit it to DUMP_BUFF_LEN.
365 */
366 ret = -ENOMEM;
367 buff_kvm_size = buff_user_len <= DUMP_BUFF_LEN ? buff_user_len : DUMP_BUFF_LEN;
368 buff_kvm = vzalloc(buff_kvm_size);
> 369 if (!buff_kvm)

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0-DAY CI Kernel Test Service, Intel Corporation