Re: lug-bg: Obst swap dql

[stoev@xxxxxxxxxxxxxxxxx (Julian Stoev)]

On Sun, May 21, 2000 at 12:40:57PM +0300, Alex Pope wrote:
|On Sun, 21 May 2000, Julian Stoev wrote:
|
|> On Sat, May 20, 2000 at 04:26:16PM +0300, Stanislav Grozev wrote:
|> |On Sat, May 20, 2000 at 02:07:11PM +0300, Georgi Chorbadzhiyski wrote:
|> |> 
|> |> Niama takiva raboti da polzva kernel-a, wizh kakvo kazva Alan Cox za vmware
|> |> 
|> |> "Vmware isnt a unix application constrained by the OS. It does hardware
|> |> level stuff of its own,"
|> |> 
|> |
|> Pa dajte da vidime koe i kak e po tozi vypros. Kyde e problema i ima
|> li problem izobshto. vmware user space programa li e izcialo ili
|> niakakva chast raboti i s prioritet na kernel? Kernela li "koli i
|> besi" ili vmware samo si byrka po hardware-to? Temata ima obshto i s
|> user-space kernelite sigurno, a ot tam i s hurd, ako shtete... 
|
|http://www.vmware.com/products/virtualplatform.html
|
|mislia che tam obshto vzeto vsichko e kazano.
|s dve dumi - ima komponent koito vyrvi v privileged mode, tova e
|t.nar. Virtual Platform Monitor (moje bi tova e modula vmmon.o). drug e
|vyprosa kakvo tochno pravi toi. tvyrdi se che izpolzva neshto narecheno
|"direct execution", za da se namali virtualization overhead-a, niakakyv
|vid harduerno multiplexirane, i tochno tova otlichava vmware ot edin
|obiknoven API emulator. vse pak, celia management na sistemnite resursi
|se izvyrshva ot host OS-a. user-space chastta na vmware pyk comunikira s
|monitora chrez device driver, narechen Virtual Platform Driver.
|

Za zyzalenie tam ima dosta razmiti izkazvania, koeto ne e
uchudvashto za komersialno prilozenie.

"For maximum portability, the device-dependent portions of
the system use the application personality and rely on the host
operating system and its device-specific driver".

"Virtual Platform (VP) Monitor - The monitor portion of Virtual
Platform runs in privileged mode directly on top of the hardware."
                 ^^^^^^^^^^
Ta znachi az ne razbrah - vyzmozno li e da se mount-ne edin i syshti
partition ednovremenno? Ako - da, tova problem li e i ako pak - da,
kyde e tozi problem? 

Cheta eto tozi pasaz "Isolation - The Virtual Platform uses hardware
protection mechanisms to isolate virtual machines from each other, and
virtual machines from the host operating system. This isolation does
not make any assumptions concerning the software that runs within the
virtual machine.  Even a rogue application or operating system is
confined to the VMware Virtual Platform sandbox."

... i ostavam s vpechatlenieto, che podoben dostyp bi triabvalo da e
nevyzmozen. 

Ako obache toi e vyzmozen, to tova e bug. Kyde?
Spored men otgovoryt moze da byde samo edin - vyv vmmon.o, kojto
raboti vyv *privileged* mode i sledovatelno ima vyzmoznost da
zaobikalia zashtitite na kernela sreshtu glupaci. Tova - dobre, ama
samia toi triabva da se grizi za tezi glupaci v takyv sluchai i da
otkazva dostyp, kogato daden partition e mount-nat veche. Logichno?
Tova oznachava, che kernelyt ne e "vinoven". Toj ne moze da se
zashtiatava ot kod rabotesht v privileged mode. 

--JS
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