On 2019-11-13 14:05, Cornelia Huck wrote:
On Wed, 13 Nov 2019 13:23:19 +0100
Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote:
This simple test test the I/O reading by the SUB Channel by:
- initializing the Channel SubSystem with predefined CSSID:
0xfe000000 CSSID for a Virtual CCW
0 should be fine with recent QEMU versions as well, I guess?
Right
0x00090000 SSID for CCW-PONG
subchannel id, or subchannel set id?
hum, only part of, I had SSID (Subchannel Set ID) 4 (a.k.a m bit) + Bit
47 =1
But as you said, I can use CSSID 0 and m = 0 which makes:
Subsystem Identification word = 0x00010000
- initializing the ORB pointing to a single READ CCW
Out of curiosity: Would using a NOP also be an option?
It will work but will not be handled by this device, css.c intercept it
in sch_handle_start_func_virtual.
AFAIU If we want to have a really good testing environment, for driver
testing for exemple, then it would be interesting to add a new
do_subchannel_work callback like do_subchannel_work_emulation along with
the _virtual and _paththrough variantes.
Having a dedicated callback for emulation, we can answer to any CSS
instructions and SSCH commands, including NOP and TIC.
My goal here was to quickly develop a device answering to some basic
READ/WRITE command to start memory transfers from inside a guest without
Linux and without implementing VIRTIO in KVM tests.
- starts the STSH command with the ORB
s/STSH/SSCH/ ?
:) yes, thanks
- Expect an interrupt
- writes the read data to output
The test implements lots of traces when DEBUG is on and
tests if memory above the stack is corrupted.
Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
---
lib/s390x/css.h | 244 +++++++++++++++++++++++++++++++++++++++++++++++++++
lib/s390x/css_dump.c | 141 +++++++++++++++++++++++++++++
s390x/Makefile | 2 +
s390x/css.c | 222 ++++++++++++++++++++++++++++++++++++++++++++++
s390x/unittests.cfg | 4 +
5 files changed, 613 insertions(+)
create mode 100644 lib/s390x/css.h
create mode 100644 lib/s390x/css_dump.c
create mode 100644 s390x/css.c
diff --git a/lib/s390x/css.h b/lib/s390x/css.h
new file mode 100644
index 0000000..a7c42fd
--- /dev/null
+++ b/lib/s390x/css.h
(...)
+static inline int rsch(unsigned long schid)
I don't think anyone has tried rsch with QEMU before; sounds like a
good idea to test this :)
With an do_subchannel_work_emulation() callback?
+{
+ register unsigned long reg1 asm("1") = schid;
+ int ccode;
+
+ asm volatile(
+ " rsch\n"
+ " ipm %0\n"
+ " srl %0,28"
+ : "=d" (ccode)
+ : "d" (reg1)
+ : "cc");
+ return ccode;
+}
+
+static inline int rchp(unsigned long chpid)
Anything useful we can test here?
Not for now.
I certainly can reduce the size of the file by removing the unused CSS
instructions calls.
...snip...
+
+static void enable_io_irq(void)
+{
+ set_io_irq_subclass_mask(0x00000000ff000000);
So, you always enable all iscs? Maybe add a comment?
OK, is just a lazy option to get IRQ for this test.
Right, I add a comment.
+ set_system_mask(PSW_PRG_MASK >> 56);
+}
+
+void handle_io_int(sregs_t *regs)
+{
+ int ret = 0;
+
+ DBG("IO IRQ: subsys_id_word=%08x", lowcore->subsys_id_word);
+ DBG("......: io_int_parm =%08x", lowcore->io_int_param);
+ DBG("......: io_int_word =%08x", lowcore->io_int_word);
+ ret = tsch(lowcore->subsys_id_word, &irb);
+ dump_irb(&irb);
+ if (ret)
+ DBG("......: tsch retval %d", ret);
+ DBG("IO IRQ: END");
+}
+
+static void set_schib(struct schib *sch)
+{
+ struct pmcw *p = &sch->pmcw;
+
+ p->intparm = 0xdeadbeef;
+ p->devnum = 0xc0ca;
+ p->lpm = 0x80;
+ p->flags = 0x3081;
Use #defines instead of magic numbers?
OK
+ p->chpid[7] = 0x22;
+ p->pim = 0x0f;
+ p->pam = 0x0f;
+ p->pom = 0x0f;
+ p->lpm = 0x0f;
+ p->lpum = 0xaa;
+ p->pnom = 0xf0;
+ p->mbi = 0xaa;
+ p->mbi = 0xaaaa;
Many of these fields are not supposed to be modifiable by the program
-- do you want to check what you get back after msch?
Also, you set mbi twice ;) (And for it to actually have any effect,
you'd have to execute SET CHANNEL MONITOR, no?)
Yes, it was for me to check what happens but I should remove most of
these field initialization.
As you said they are not modifiable by the program.
Will clean this.
+}
+
+static void css_enable(void)
+{
+ int ret;
+
+ ret = stsch(CSSID_PONG, &schib);
+ if (ret)
+ DBG("stsch: %x\n", ret);
+ dump_schib(&schib);
+ set_schib(&schib);
+ dump_schib(&schib);
+ ret = msch(CSSID_PONG, &schib);
+ if (ret)
+ DBG("msch : %x\n", ret);
+}
+
+/* These two definitions are part of the QEMU PONG interface */
+#define PONG_WRITE 0x21
+#define PONG_READ 0x22
Ah, so it's not a plain read/write, but a specialized one? Mention that
in the patch description?
+
+static int css_run(int fake)
+{
+ struct orb *p = orb;
I'd maybe call that variable 'orb' instead; at a glance, I was confused
what you did with the pmcw below, until I realized that it's the orb :)
OK, is clearly better to use orb.
Thanks,
Pierre
--
Pierre Morel
IBM Lab Boeblingen
