Re: [RFC 17/37] DOCUMENTATION: protvirt: Instruction emulation

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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?

Attachment: pgpBZWV_Rr0zO.pgp
Description: OpenPGP digital signature


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Kernel Development]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite Info]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Linux Media]     [Device Mapper]

  Powered by Linux