On 11/14/19 5:03 PM, Cornelia Huck wrote: > On Thu, 14 Nov 2019 16:55:46 +0100 > Janosch Frank <frankja@xxxxxxxxxxxxx> wrote: > >> On 11/14/19 4:41 PM, Cornelia Huck wrote: >>> On Thu, 14 Nov 2019 16:20:24 +0100 >>> Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx> wrote: >>> >>>> On Thu, 14 Nov 2019 16:15:26 +0100 >>>> Cornelia Huck <cohuck@xxxxxxxxxx> wrote: >>>> >>>>> On Thu, 24 Oct 2019 07:40:39 -0400 >>>>> Janosch Frank <frankja@xxxxxxxxxxxxx> wrote: > >>>>>> +The Secure Instruction Data Area contains instruction storage >>>>>> +data. Data for diag 500 is exempt from that and has to be moved >>>>>> +through shared buffers to KVM. >>>>> >>>>> I find this paragraph a bit confusing. What does that imply for diag >>>>> 500 interception? Data is still present in gprs 1-4? >>>> >>>> no registers are leaked in the registers. registers are always only >>>> exposed through the state description. >>> >>> So, what is so special about diag 500, then? >> >> That's mostly a confusion on my side. >> The SIDAD is 4k max, so we can only move IO "management" data over it >> like ORBs and stuff. My intention was to point out, that the data which >> is to be transferred (disk contents, etc.) can't go over the SIDAD but >> needs to be in a shared page. >> >> diag500 was mostly a notification mechanism without a lot of data, right? > > Yes; the main information in there are the schid identifying the > subchannel, the virtqueue number, and a cookie value, all of which fit > into the registers. > > So this goes via the sidad as well? > Only referenced data goes over the SIDA, register values go into offset 0x380 of the SIE state description. If an instruction has an address in a register, we will receive a bogus address and the referenced data in the SIDA. SCLP has a code and an address as register values. We will get the code and a bogus address in the register area. The SCCB will be in the SIDA.
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