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?
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