Re: [Xen-devel] Xen PV: Sample new PV driver for buffer sharing between domains

[Omkar Bolla <omkar.bolla@xxxxxxxxxxxxxxxxxxx>]

Hi,

Thanks,

Basic state change is working now, after using above script.

As I said, I want to share buffer between two domains.

Could you please suggest outlines, how can I share buffer between 2 domains(Guest and Host)?

Thanks,

Omkar B

On Fri, Sep 28, 2018 at 7:12 PM Juergen Gross <jgross@xxxxxxxx> wrote:

On 28/09/2018 14:55, Omkar Bolla wrote:
> Hi,
> I tried to run script after pause the domain and unpause domain after
> run script. But I ended up with same error

I looked at the script again, it is wrong. The permissions should
be set for each node under the root path of the respective domains,
the first permission should be "n$domid" ($domid is the owner who
can always read/write, the n is "no access" for all domains not
explicitly listed), the second permission should be "r$domid" as
the other side should be able to read only.

In order to do it correctly the script should be:

#!/bin/bash

DOMU_ID=$1

if [ -z "$DOMU_ID"  ]; then
  echo "Usage: $0 [domU ID]]"
  echo
  echo "Connects the new device, with dom0 as backend, domU as frontend"
  exit 1
fi

# Pause domU as a script can't write an entry and set permission
# in a single operation.
xl pause $DOMU_ID

DEVICE=mydevice
DOMU_KEY=/local/domain/$DOMU_ID/device/$DEVICE/0
DOM0_KEY=/local/domain/0/backend/$DEVICE/$DOMU_ID/0

# Tell the domU about the new device and its backend
xenstore-write $DOMU_KEY/backend-id 0
xenstore-write $DOMU_KEY/backend
"/local/domain/0/backend/$DEVICE/$DOMU_ID/0"

# Tell the dom0 about the new device and its frontend
xenstore-write $DOM0_KEY/frontend-id $DOMU_ID
xenstore-write $DOM0_KEY/frontend "/local/domain/$DOMU_ID/device/$DEVICE/0"

# Activate the device, dom0 needs to be activated last
xenstore-write $DOMU_KEY/state 1
xenstore-write $DOM0_KEY/state 1

# Make sure the domU can read the dom0 data
xenstore-chmod -r $DOM0_KEY n0 r$DOMU_ID
xenstore-chmod -r $DOMU_KEY n$DOMU_ID r0

xl unpause $DOMU_ID


Juergen

This message contains confidential information and is intended only for the individual(s) named. If you are not the intended recipient, you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this mail and attached file/s is strictly prohibited. Please notify the sender immediately and delete this e-mail from your system. E-mail transmission cannot be guaranteed to be secured or error-free as information could be intercepted, corrupted, lost, destroyed, arrive late or incomplete, or contain viruses. The sender therefore does not accept liability for any errors or omissions in the contents of this message, which arise as a result of e-mail transmission.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel