| Message ID | 20210121065703.561444-1-thuth@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [kvm-unit-tests] lib/s390x/sclp: Clarify that the CPUEntry array could be at a different spot | expand |
On Thu, 21 Jan 2021 07:57:03 +0100 Thomas Huth <thuth@redhat.com> wrote: > The "struct CPUEntry entries[0]" in the ReadInfo structure is misleading > since the entries could be add a completely different spot. Replace it s/add/at/ > by a proper comment instead. > > Signed-off-by: Thomas Huth <thuth@redhat.com> > --- > lib/s390x/sclp.h | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/lib/s390x/sclp.h b/lib/s390x/sclp.h > index 9f81c0f..8523133 100644 > --- a/lib/s390x/sclp.h > +++ b/lib/s390x/sclp.h > @@ -131,10 +131,15 @@ typedef struct ReadInfo { > uint16_t highest_cpu; > uint8_t _reserved5[124 - 122]; /* 122-123 */ > uint32_t hmfai; > - uint8_t reserved7[134 - 128]; > + uint8_t reserved7[134 - 128]; /* 128-133 */ > uint8_t byte_134_diag318 : 1; > uint8_t : 7; > - struct CPUEntry entries[0]; > + /* > + * At the end of the ReadInfo, there are also the CPU entries (see > + * struct CPUEntry). When the Extended-Length SCCB (ELS) feature is > + * enabled, the start of the CPU entries array begins at an offset > + * denoted by the offset_cpu field, otherwise it's at offset 128. > + */ This comment is really helpful, as the difference for ELS had actually slipped my mind again... > } __attribute__((packed)) ReadInfo; > > typedef struct ReadCpuInfo { Reviewed-by: Cornelia Huck <cohuck@redhat.com>
On 21.01.21 07:57, Thomas Huth wrote: > The "struct CPUEntry entries[0]" in the ReadInfo structure is misleading > since the entries could be add a completely different spot. Replace it > by a proper comment instead. > > Signed-off-by: Thomas Huth <thuth@redhat.com> > --- > lib/s390x/sclp.h | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/lib/s390x/sclp.h b/lib/s390x/sclp.h > index 9f81c0f..8523133 100644 > --- a/lib/s390x/sclp.h > +++ b/lib/s390x/sclp.h > @@ -131,10 +131,15 @@ typedef struct ReadInfo { > uint16_t highest_cpu; > uint8_t _reserved5[124 - 122]; /* 122-123 */ > uint32_t hmfai; > - uint8_t reserved7[134 - 128]; > + uint8_t reserved7[134 - 128]; /* 128-133 */ > uint8_t byte_134_diag318 : 1; > uint8_t : 7; > - struct CPUEntry entries[0]; > + /* > + * At the end of the ReadInfo, there are also the CPU entries (see > + * struct CPUEntry). When the Extended-Length SCCB (ELS) feature is > + * enabled, the start of the CPU entries array begins at an offset > + * denoted by the offset_cpu field, otherwise it's at offset 128. > + */ > } __attribute__((packed)) ReadInfo; > > typedef struct ReadCpuInfo { > Reviewed-by: David Hildenbrand <david@redhat.com>
On 1/21/21 7:57 AM, Thomas Huth wrote: > The "struct CPUEntry entries[0]" in the ReadInfo structure is misleading > since the entries could be add a completely different spot. Replace it > by a proper comment instead. > > Signed-off-by: Thomas Huth <thuth@redhat.com> Thanks, picked. I'll fix up Conny's comment. > --- > lib/s390x/sclp.h | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/lib/s390x/sclp.h b/lib/s390x/sclp.h > index 9f81c0f..8523133 100644 > --- a/lib/s390x/sclp.h > +++ b/lib/s390x/sclp.h > @@ -131,10 +131,15 @@ typedef struct ReadInfo { > uint16_t highest_cpu; > uint8_t _reserved5[124 - 122]; /* 122-123 */ > uint32_t hmfai; > - uint8_t reserved7[134 - 128]; > + uint8_t reserved7[134 - 128]; /* 128-133 */ > uint8_t byte_134_diag318 : 1; > uint8_t : 7; > - struct CPUEntry entries[0]; > + /* > + * At the end of the ReadInfo, there are also the CPU entries (see > + * struct CPUEntry). When the Extended-Length SCCB (ELS) feature is > + * enabled, the start of the CPU entries array begins at an offset > + * denoted by the offset_cpu field, otherwise it's at offset 128. > + */ > } __attribute__((packed)) ReadInfo; > > typedef struct ReadCpuInfo { >
diff --git a/lib/s390x/sclp.h b/lib/s390x/sclp.h index 9f81c0f..8523133 100644 --- a/lib/s390x/sclp.h +++ b/lib/s390x/sclp.h @@ -131,10 +131,15 @@ typedef struct ReadInfo { uint16_t highest_cpu; uint8_t _reserved5[124 - 122]; /* 122-123 */ uint32_t hmfai; - uint8_t reserved7[134 - 128]; + uint8_t reserved7[134 - 128]; /* 128-133 */ uint8_t byte_134_diag318 : 1; uint8_t : 7; - struct CPUEntry entries[0]; + /* + * At the end of the ReadInfo, there are also the CPU entries (see + * struct CPUEntry). When the Extended-Length SCCB (ELS) feature is + * enabled, the start of the CPU entries array begins at an offset + * denoted by the offset_cpu field, otherwise it's at offset 128. + */ } __attribute__((packed)) ReadInfo; typedef struct ReadCpuInfo {
The "struct CPUEntry entries[0]" in the ReadInfo structure is misleading since the entries could be add a completely different spot. Replace it by a proper comment instead. Signed-off-by: Thomas Huth <thuth@redhat.com> --- lib/s390x/sclp.h | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)