From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:33962 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233584AbhBCKKk (ORCPT ); Wed, 3 Feb 2021 05:10:40 -0500 Subject: Re: [kvm-unit-tests PATCH v1 3/5] s390x: css: implementing Set CHannel Monitor References: <1611930869-25745-1-git-send-email-pmorel@linux.ibm.com> <1611930869-25745-4-git-send-email-pmorel@linux.ibm.com> <3a0aade0-510b-adaa-e956-3dddc23388ba@redhat.com> From: Pierre Morel Message-ID: Date: Wed, 3 Feb 2021 11:09:52 +0100 MIME-Version: 1.0 In-Reply-To: <3a0aade0-510b-adaa-e956-3dddc23388ba@redhat.com> Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Language: en-US Content-Transfer-Encoding: 8bit List-ID: To: Thomas Huth , kvm@vger.kernel.org Cc: linux-s390@vger.kernel.org, frankja@linux.ibm.com, david@redhat.com, cohuck@redhat.com, imbrenda@linux.ibm.com On 2/2/21 6:32 PM, Thomas Huth wrote: > On 29/01/2021 15.34, Pierre Morel wrote: >> We implement the call of the Set CHannel Monitor instruction, >> starting the monitoring of the all Channel Sub System, and >> the initialization of the monitoring on a Sub Channel. >> >> An initial test reports the presence of the extended measurement >> block feature. >> >> Signed-off-by: Pierre Morel >> --- >>   lib/s390x/css.h     | 17 +++++++++- >>   lib/s390x/css_lib.c | 77 +++++++++++++++++++++++++++++++++++++++++++++ >>   s390x/css.c         |  7 +++++ >>   3 files changed, 100 insertions(+), 1 deletion(-) >> >> diff --git a/lib/s390x/css.h b/lib/s390x/css.h >> index f8bfa37..938f0ab 100644 >> --- a/lib/s390x/css.h >> +++ b/lib/s390x/css.h >> @@ -82,6 +82,7 @@ struct pmcw { >>       uint32_t intparm; >>   #define PMCW_DNV    0x0001 >>   #define PMCW_ENABLE    0x0080 >> +#define PMCW_MBUE    0x0010 >>   #define PMCW_ISC_MASK    0x3800 >>   #define PMCW_ISC_SHIFT    11 >>       uint16_t flags; >> @@ -94,6 +95,7 @@ struct pmcw { >>       uint8_t  pom; >>       uint8_t  pam; >>       uint8_t  chpid[8]; >> +#define PMCW_MBF1    0x0004 >>       uint32_t flags2; >>   }; >>   #define PMCW_CHANNEL_TYPE(pmcw) (pmcw->flags2 >> 21) >> @@ -101,7 +103,8 @@ struct pmcw { >>   struct schib { >>       struct pmcw pmcw; >>       struct scsw scsw; >> -    uint8_t  md[12]; >> +    uint64_t mbo; >> +    uint8_t  md[4]; >>   } __attribute__ ((aligned(4))); >>   struct irb { >> @@ -305,6 +308,7 @@ struct chsc_scsc { >>       u32 reserved3; >>       struct chsc_header res; >>       u32 format; >> +#define CSSC_EXTENDED_MEASUREMENT_BLOCK 48 >>       u64 general_char[255]; >>       u64 chsc_char[254]; >>   }; >> @@ -346,4 +350,15 @@ static inline int chsc(void *p, uint16_t code, >> uint16_t len) >>   #define css_general_feature(bit) test_bit_inv(bit, >> chsc_scsc->general_char) >>   #define css_chsc_feature(bit) test_bit_inv(bit, chsc_scsc->chsc_char) >> +static inline void schm(void *mbo, unsigned int flags) >> +{ >> +    register void *__gpr2 asm("2") = mbo; >> +    register long __gpr1 asm("1") = flags; >> + >> +    asm("schm" : : "d" (__gpr2), "d" (__gpr1)); >> +} >> + >> +int css_enable_mb(int schid, uint64_t mb, int format1, uint16_t mbi, >> +          uint16_t flags); >> + >>   #endif >> diff --git a/lib/s390x/css_lib.c b/lib/s390x/css_lib.c >> index f300969..9e0f568 100644 >> --- a/lib/s390x/css_lib.c >> +++ b/lib/s390x/css_lib.c >> @@ -205,6 +205,83 @@ retry: >>       return -1; >>   } >> +/* >> + * css_enable_mb: enable the subchannel Mesurement Block >> + * @schid: Subchannel Identifier >> + * @mb   : 64bit address of the measurement block >> + * @format1: set if format 1 is to be used >> + * @mbi : the measurement block offset >> + * @flags : PMCW_MBUE to enable measurement block update >> + *        PMCW_DCTME to enable device connect time >> + * Return value: >> + *   On success: 0 >> + *   On error the CC of the faulty instruction >> + *      or -1 if the retry count is exceeded. >> + */ >> +int css_enable_mb(int schid, uint64_t mb, int format1, uint16_t mbi, >> +          uint16_t flags) >> +{ >> +    struct pmcw *pmcw = &schib.pmcw; >> +    int retry_count = 0; >> +    int cc; >> + >> +    /* Read the SCHIB for this subchannel */ >> +    cc = stsch(schid, &schib); >> +    if (cc) { >> +        report_info("stsch: sch %08x failed with cc=%d", schid, cc); >> +        return cc; >> +    } >> + >> +retry: >> +    /* Update the SCHIB to enable the measurement block */ >> +    pmcw->flags |= flags; >> + >> +    if (format1) >> +        pmcw->flags2 |= PMCW_MBF1; >> +    else >> +        pmcw->flags2 &= ~PMCW_MBF1; >> + >> +    pmcw->mbi = mbi; >> +    schib.mbo = mb; >> + >> +    /* Tell the CSS we want to modify the subchannel */ >> +    cc = msch(schid, &schib); >> +    if (cc) { >> +        /* >> +         * If the subchannel is status pending or >> +         * if a function is in progress, >> +         * we consider both cases as errors. >> +         */ >> +        report_info("msch: sch %08x failed with cc=%d", schid, cc); >> +        return cc; >> +    } >> + >> +    /* >> +     * Read the SCHIB again to verify the measurement block origin >> +     */ >> +    cc = stsch(schid, &schib); >> +    if (cc) { >> +        report_info("stsch: updating sch %08x failed with cc=%d", >> +                schid, cc); >> +        return cc; >> +    } >> + >> +    if (schib.mbo == mb) { >> +        report_info("stsch: sch %08x successfully modified after %d >> retries", >> +                schid, retry_count); >> +        return 0; >> +    } >> + >> +    if (retry_count++ < MAX_ENABLE_RETRIES) { >> +        mdelay(10); /* the hardware was not ready, give it some time */ >> +        goto retry; >> +    } > > "goto retries" are always a good indication that you likely should use a > proper loop instead. And maybe put the code in the loop body into a > separate function? Yes, thanks, I do so. Regards, Pierre -- Pierre Morel IBM Lab Boeblingen