| Message ID | 1575649588-6127-8-git-send-email-pmorel@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | s390x: Testing the Channel Subsystem I/O | expand |
On Fri, 6 Dec 2019 17:26:26 +0100 Pierre Morel <pmorel@linux.ibm.com> wrote: > A second step when testing the channel subsystem is to prepare a channel > for use. > This includes: > - Get the current SubCHannel Information Block (SCHIB) using STSCH > - Update it in memory to set the ENABLE bit > - Tell the CSS that the SCHIB has been modified using MSCH > - Get the SCHIB from the CSS again to verify that the subchannel is > enabled. > > This tests the success of the MSCH instruction by enabling a channel. > > Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> > --- > s390x/css.c | 39 +++++++++++++++++++++++++++++++++++++++ > 1 file changed, 39 insertions(+) > > diff --git a/s390x/css.c b/s390x/css.c > index 3d4a986..4c0031c 100644 > --- a/s390x/css.c > +++ b/s390x/css.c > @@ -58,11 +58,50 @@ static void test_enumerate(void) > report("Tested %d devices, %d found", 1, scn, found); > } > > +static void test_enable(void) > +{ > + struct pmcw *pmcw = &schib.pmcw; > + int cc; > + > + if (!test_device_sid) { > + report_skip("No device"); > + return; > + } > + /* Read the SCIB for this subchannel */ s/SCIB/SCHIB/ > + cc = stsch(test_device_sid, &schib); > + if (cc) { > + report("stsch cc=%d", 0, cc); > + return; > + } > + /* Update the SCHIB to enable the channel */ > + pmcw->flags |= PMCW_ENABLE; > + > + /* Tell the CSS we want to modify the subchannel */ > + cc = msch(test_device_sid, &schib); > + if (cc) { > + report("msch cc=%d", 0, cc); So you expect the subchannel to be idle? Probably true, especially as QEMU has no reason to post an unsolicited interrupt for a test device. > + return; > + } > + > + /* Read the SCHIB again to verify the enablement */ > + cc = stsch(test_device_sid, &schib); > + if (cc) { > + report("stsch cc=%d", 0, cc); > + return; > + } > + if (!(pmcw->flags & PMCW_ENABLE)) { > + report("Enable failed. pmcw: %x", 0, pmcw->flags); This check is fine when running under KVM. If this test is modified to run under z/VM in the future, you probably should retry here: I've seen the enable bit 'stick' only after the second msch() there. > + return; > + } > + report("Tested", 1); > +} > + > static struct { > const char *name; > void (*func)(void); > } tests[] = { > { "enumerate (stsch)", test_enumerate }, > + { "enable (msch)", test_enable }, > { NULL, NULL } > }; >
On 2019-12-09 17:54, Cornelia Huck wrote: > On Fri, 6 Dec 2019 17:26:26 +0100 > Pierre Morel <pmorel@linux.ibm.com> wrote: > >> A second step when testing the channel subsystem is to prepare a channel >> for use. >> This includes: >> - Get the current SubCHannel Information Block (SCHIB) using STSCH >> - Update it in memory to set the ENABLE bit >> - Tell the CSS that the SCHIB has been modified using MSCH >> - Get the SCHIB from the CSS again to verify that the subchannel is >> enabled. >> >> This tests the success of the MSCH instruction by enabling a channel. >> >> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> >> --- >> s390x/css.c | 39 +++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 39 insertions(+) >> >> diff --git a/s390x/css.c b/s390x/css.c >> index 3d4a986..4c0031c 100644 >> --- a/s390x/css.c >> +++ b/s390x/css.c >> @@ -58,11 +58,50 @@ static void test_enumerate(void) >> report("Tested %d devices, %d found", 1, scn, found); >> } >> >> +static void test_enable(void) >> +{ >> + struct pmcw *pmcw = &schib.pmcw; >> + int cc; >> + >> + if (!test_device_sid) { >> + report_skip("No device"); >> + return; >> + } >> + /* Read the SCIB for this subchannel */ > > s/SCIB/SCHIB/ yes > >> + cc = stsch(test_device_sid, &schib); >> + if (cc) { >> + report("stsch cc=%d", 0, cc); >> + return; >> + } >> + /* Update the SCHIB to enable the channel */ >> + pmcw->flags |= PMCW_ENABLE; >> + >> + /* Tell the CSS we want to modify the subchannel */ >> + cc = msch(test_device_sid, &schib); >> + if (cc) { >> + report("msch cc=%d", 0, cc); > > So you expect the subchannel to be idle? Probably true, especially as > QEMU has no reason to post an unsolicited interrupt for a test device. > >> + return; >> + } >> + >> + /* Read the SCHIB again to verify the enablement */ >> + cc = stsch(test_device_sid, &schib); >> + if (cc) { >> + report("stsch cc=%d", 0, cc); >> + return; >> + } >> + if (!(pmcw->flags & PMCW_ENABLE)) { >> + report("Enable failed. pmcw: %x", 0, pmcw->flags); > > This check is fine when running under KVM. If this test is modified to > run under z/VM in the future, you probably should retry here: I've seen > the enable bit 'stick' only after the second msch() there. Oh. Thanks, may be I can loop with a delay and count. If I need to do this may be I need to create dedicated sub-functions to include the sanity tests. > >> + return; >> + } >> + report("Tested", 1); >> +} >> + >> static struct { >> const char *name; >> void (*func)(void); >> } tests[] = { >> { "enumerate (stsch)", test_enumerate }, >> + { "enable (msch)", test_enable }, >> { NULL, NULL } >> }; >> >
On Tue, 10 Dec 2019 10:01:46 +0100 Pierre Morel <pmorel@linux.ibm.com> wrote: > On 2019-12-09 17:54, Cornelia Huck wrote: > > On Fri, 6 Dec 2019 17:26:26 +0100 > > Pierre Morel <pmorel@linux.ibm.com> wrote: > > > >> A second step when testing the channel subsystem is to prepare a channel > >> for use. > >> This includes: > >> - Get the current SubCHannel Information Block (SCHIB) using STSCH > >> - Update it in memory to set the ENABLE bit > >> - Tell the CSS that the SCHIB has been modified using MSCH > >> - Get the SCHIB from the CSS again to verify that the subchannel is > >> enabled. > >> > >> This tests the success of the MSCH instruction by enabling a channel. > >> > >> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> > >> --- > >> s390x/css.c | 39 +++++++++++++++++++++++++++++++++++++++ > >> 1 file changed, 39 insertions(+) > >> > >> diff --git a/s390x/css.c b/s390x/css.c > >> index 3d4a986..4c0031c 100644 > >> --- a/s390x/css.c > >> +++ b/s390x/css.c > >> @@ -58,11 +58,50 @@ static void test_enumerate(void) > >> report("Tested %d devices, %d found", 1, scn, found); > >> } > >> > >> +static void test_enable(void) > >> +{ > >> + struct pmcw *pmcw = &schib.pmcw; > >> + int cc; > >> + > >> + if (!test_device_sid) { > >> + report_skip("No device"); > >> + return; > >> + } > >> + /* Read the SCIB for this subchannel */ > > > > s/SCIB/SCHIB/ > > yes > > > > >> + cc = stsch(test_device_sid, &schib); > >> + if (cc) { > >> + report("stsch cc=%d", 0, cc); > >> + return; > >> + } > >> + /* Update the SCHIB to enable the channel */ > >> + pmcw->flags |= PMCW_ENABLE; > >> + > >> + /* Tell the CSS we want to modify the subchannel */ > >> + cc = msch(test_device_sid, &schib); > >> + if (cc) { > >> + report("msch cc=%d", 0, cc); > > > > So you expect the subchannel to be idle? Probably true, especially as > > QEMU has no reason to post an unsolicited interrupt for a test device. > > > >> + return; > >> + } > >> + > >> + /* Read the SCHIB again to verify the enablement */ > >> + cc = stsch(test_device_sid, &schib); > >> + if (cc) { > >> + report("stsch cc=%d", 0, cc); > >> + return; > >> + } > >> + if (!(pmcw->flags & PMCW_ENABLE)) { > >> + report("Enable failed. pmcw: %x", 0, pmcw->flags); > > > > This check is fine when running under KVM. If this test is modified to > > run under z/VM in the future, you probably should retry here: I've seen > > the enable bit 'stick' only after the second msch() there. > > Oh. Thanks, may be I can loop with a delay and count. FWIW, the Linux kernel code is trying 5 times. > If I need to do this may be I need to create dedicated sub-functions to > include the sanity tests. I'm not sure how worthwhile investing time here is, actually: If you don't plan to run under anything but KVM, you won't need it. I'm not sure if current versions of z/VM still display the same behaviour (it has been some time...); on the other hand, it is compliant with the architecture... > > > > >> + return; > >> + } > >> + report("Tested", 1); > >> +} > >> + > >> static struct { > >> const char *name; > >> void (*func)(void); > >> } tests[] = { > >> { "enumerate (stsch)", test_enumerate }, > >> + { "enable (msch)", test_enable }, > >> { NULL, NULL } > >> }; > >> > > >
On 2019-12-10 10:09, Cornelia Huck wrote: > On Tue, 10 Dec 2019 10:01:46 +0100 > Pierre Morel <pmorel@linux.ibm.com> wrote: > >> On 2019-12-09 17:54, Cornelia Huck wrote: >>> On Fri, 6 Dec 2019 17:26:26 +0100 >>> Pierre Morel <pmorel@linux.ibm.com> wrote: >>> >>>> A second step when testing the channel subsystem is to prepare a channel >>>> for use. >>>> This includes: >>>> - Get the current SubCHannel Information Block (SCHIB) using STSCH >>>> - Update it in memory to set the ENABLE bit >>>> - Tell the CSS that the SCHIB has been modified using MSCH >>>> - Get the SCHIB from the CSS again to verify that the subchannel is >>>> enabled. >>>> >>>> This tests the success of the MSCH instruction by enabling a channel. >>>> >>>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> >>>> --- >>>> s390x/css.c | 39 +++++++++++++++++++++++++++++++++++++++ >>>> 1 file changed, 39 insertions(+) >>>> >>>> diff --git a/s390x/css.c b/s390x/css.c >>>> index 3d4a986..4c0031c 100644 >>>> --- a/s390x/css.c >>>> +++ b/s390x/css.c >>>> @@ -58,11 +58,50 @@ static void test_enumerate(void) >>>> report("Tested %d devices, %d found", 1, scn, found); >>>> } >>>> >>>> +static void test_enable(void) >>>> +{ >>>> + struct pmcw *pmcw = &schib.pmcw; >>>> + int cc; >>>> + >>>> + if (!test_device_sid) { >>>> + report_skip("No device"); >>>> + return; >>>> + } >>>> + /* Read the SCIB for this subchannel */ >>> >>> s/SCIB/SCHIB/ >> >> yes >> >>> >>>> + cc = stsch(test_device_sid, &schib); >>>> + if (cc) { >>>> + report("stsch cc=%d", 0, cc); >>>> + return; >>>> + } >>>> + /* Update the SCHIB to enable the channel */ >>>> + pmcw->flags |= PMCW_ENABLE; >>>> + >>>> + /* Tell the CSS we want to modify the subchannel */ >>>> + cc = msch(test_device_sid, &schib); >>>> + if (cc) { >>>> + report("msch cc=%d", 0, cc); >>> >>> So you expect the subchannel to be idle? Probably true, especially as >>> QEMU has no reason to post an unsolicited interrupt for a test device. >>> >>>> + return; >>>> + } >>>> + >>>> + /* Read the SCHIB again to verify the enablement */ >>>> + cc = stsch(test_device_sid, &schib); >>>> + if (cc) { >>>> + report("stsch cc=%d", 0, cc); >>>> + return; >>>> + } >>>> + if (!(pmcw->flags & PMCW_ENABLE)) { >>>> + report("Enable failed. pmcw: %x", 0, pmcw->flags); >>> >>> This check is fine when running under KVM. If this test is modified to >>> run under z/VM in the future, you probably should retry here: I've seen >>> the enable bit 'stick' only after the second msch() there. >> >> Oh. Thanks, may be I can loop with a delay and count. > > FWIW, the Linux kernel code is trying 5 times. > >> If I need to do this may be I need to create dedicated sub-functions to >> include the sanity tests. > > I'm not sure how worthwhile investing time here is, actually: If you > don't plan to run under anything but KVM, you won't need it. I'm not > sure if current versions of z/VM still display the same behaviour (it > has been some time...); on the other hand, it is compliant with the > architecture... OK, I just insert the retry. Thanks, Pierre
diff --git a/s390x/css.c b/s390x/css.c index 3d4a986..4c0031c 100644 --- a/s390x/css.c +++ b/s390x/css.c @@ -58,11 +58,50 @@ static void test_enumerate(void) report("Tested %d devices, %d found", 1, scn, found); } +static void test_enable(void) +{ + struct pmcw *pmcw = &schib.pmcw; + int cc; + + if (!test_device_sid) { + report_skip("No device"); + return; + } + /* Read the SCIB for this subchannel */ + cc = stsch(test_device_sid, &schib); + if (cc) { + report("stsch cc=%d", 0, cc); + return; + } + /* Update the SCHIB to enable the channel */ + pmcw->flags |= PMCW_ENABLE; + + /* Tell the CSS we want to modify the subchannel */ + cc = msch(test_device_sid, &schib); + if (cc) { + report("msch cc=%d", 0, cc); + return; + } + + /* Read the SCHIB again to verify the enablement */ + cc = stsch(test_device_sid, &schib); + if (cc) { + report("stsch cc=%d", 0, cc); + return; + } + if (!(pmcw->flags & PMCW_ENABLE)) { + report("Enable failed. pmcw: %x", 0, pmcw->flags); + return; + } + report("Tested", 1); +} + static struct { const char *name; void (*func)(void); } tests[] = { { "enumerate (stsch)", test_enumerate }, + { "enable (msch)", test_enable }, { NULL, NULL } };
A second step when testing the channel subsystem is to prepare a channel for use. This includes: - Get the current SubCHannel Information Block (SCHIB) using STSCH - Update it in memory to set the ENABLE bit - Tell the CSS that the SCHIB has been modified using MSCH - Get the SCHIB from the CSS again to verify that the subchannel is enabled. This tests the success of the MSCH instruction by enabling a channel. Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> --- s390x/css.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+)