On 09.05.20 01:08, Collin Walling wrote: > Let's factor out the SCLP boundary and length checks > into separate functions. > > Signed-off-by: Collin Walling <wall...@linux.ibm.com> > --- > hw/s390x/sclp.c | 41 +++++++++++++++++++++++++++++++++++------ > 1 file changed, 35 insertions(+), 6 deletions(-) > > diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c > index d08a291e40..470d5da7a2 100644 > --- a/hw/s390x/sclp.c > +++ b/hw/s390x/sclp.c > @@ -49,6 +49,34 @@ static inline bool sclp_command_code_valid(uint32_t code) > return false; > } > > +static bool check_sccb_boundary_valid(uint64_t sccb_addr, uint32_t code, > + SCCB *sccb)
I suggest naming this "has_valid_sccb_boundary", then the true/false response is clearer. > +{ > + uint64_t current_len = sccb_addr + be16_to_cpu(sccb->h.length); > + uint64_t allowed_len = (sccb_addr & PAGE_MASK) + PAGE_SIZE; > + > + switch (code & SCLP_CMD_CODE_MASK) { > + default: > + if (current_len <= allowed_len) { > + return true; > + } > + } > + sccb->h.response_code = cpu_to_be16(SCLP_RC_SCCB_BOUNDARY_VIOLATION); > + return false; > +} > + > +static bool check_sufficient_sccb_len(SCCB *sccb, int size) "has_sufficient_sccb_len" ? > +{ > + MachineState *ms = MACHINE(qdev_get_machine()); > + int required_len = size + ms->possible_cpus->len * sizeof(CPUEntry); Rather pass in the number of cpus instead. Looking up the machine again in here is ugly. > + > + if (be16_to_cpu(sccb->h.length) < required_len) { > + sccb->h.response_code = > cpu_to_be16(SCLP_RC_INSUFFICIENT_SCCB_LENGTH); > + return false; > + } > + return true; > +} > + > static void prepare_cpu_entries(CPUEntry *entry, int *count) > { > MachineState *ms = MACHINE(qdev_get_machine()); > @@ -76,8 +104,7 @@ static void read_SCP_info(SCLPDevice *sclp, SCCB *sccb) > int rnsize, rnmax; > IplParameterBlock *ipib = s390_ipl_get_iplb(); > > - if (be16_to_cpu(sccb->h.length) < (sizeof(ReadInfo) + cpu_count * > sizeof(CPUEntry))) { > - sccb->h.response_code = > cpu_to_be16(SCLP_RC_INSUFFICIENT_SCCB_LENGTH); > + if (!check_sufficient_sccb_len(sccb, sizeof(ReadInfo))) { > return; > } > > @@ -134,8 +161,7 @@ static void sclp_read_cpu_info(SCLPDevice *sclp, SCCB > *sccb) > ReadCpuInfo *cpu_info = (ReadCpuInfo *) sccb; > int cpu_count; > > - if (be16_to_cpu(sccb->h.length) < (sizeof(ReadCpuInfo) + cpu_count * > sizeof(CPUEntry))) { > - sccb->h.response_code = > cpu_to_be16(SCLP_RC_INSUFFICIENT_SCCB_LENGTH); > + if (!check_sufficient_sccb_len(sccb, sizeof(ReadCpuInfo))) { > return; > } > > @@ -227,6 +253,10 @@ int sclp_service_call_protected(CPUS390XState *env, > uint64_t sccb, > goto out_write; > } > > + if (!check_sccb_boundary_valid(sccb, code, &work_sccb)) { > + goto out_write; > + } This is not a "factor out". You're adding new code, this needs justification in the patch description. > + > sclp_c->execute(sclp, &work_sccb, code); > out_write: > s390_cpu_pv_mem_write(env_archcpu(env), 0, &work_sccb, > @@ -272,8 +302,7 @@ int sclp_service_call(CPUS390XState *env, uint64_t sccb, > uint32_t code) > goto out_write; > } > > - if ((sccb + be16_to_cpu(work_sccb.h.length)) > ((sccb & PAGE_MASK) + > PAGE_SIZE)) { > - work_sccb.h.response_code = > cpu_to_be16(SCLP_RC_SCCB_BOUNDARY_VIOLATION); > + if (!check_sccb_boundary_valid(sccb, code, &work_sccb)) { > goto out_write; > } > > -- Thanks, David / dhildenb