hi, I am mapping some pages in a domU from dom0 userspace. Doing that once I know the page numbers is fairly trivial, but what is the recommended way of communicating one or more page numbers from domU to dom0, hopefully without having to modify xend? Right now I just copy&paste from the console, but that seems uncool somehow ;-) thanks, Jacob ------------------------------------------------------- This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting Tool for open source databases. Create drag-&-drop reports. Save time by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. Download a FREE copy at http://www.intelliview.com/go/osdn_nl _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
> I am mapping some pages in a domU from dom0 userspace. Doing that once I > know the page numbers is fairly trivial, but what is the recommended way > of communicating one or more page numbers from domU to dom0, hopefully > without having to modify xend?Hrrrm. There was talk of a simple generic control message that could be used for this sort of thing but I''m not sure if it''s been implemented.> Right now I just copy&paste from the console, but that seems uncool > somehow ;-)There''s always the network, although that''s kinda gross ;-) Cheers, Mark ------------------------------------------------------- This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting Tool for open source databases. Create drag-&-drop reports. Save time by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. Download a FREE copy at http://www.intelliview.com/go/osdn_nl _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
Mark Williamson wrote:>>I am mapping some pages in a domU from dom0 userspace. Doing that once I >>know the page numbers is fairly trivial, but what is the recommended way >>of communicating one or more page numbers from domU to dom0, hopefully >>without having to modify xend? > > > Hrrrm. There was talk of a simple generic control message that could be used > for this sort of thing but I''m not sure if it''s been implemented.Sad. I tried sticking this at the last four bytes of the shared_info page, but apparently that one gets cleared every now and then :-( Jacob ------------------------------------------------------- This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting Tool for open source databases. Create drag-&-drop reports. Save time by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. Download a FREE copy at http://www.intelliview.com/go/osdn_nl _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
Jacob Gorm Hansen wrote:> Mark Williamson wrote: > >>> I am mapping some pages in a domU from dom0 userspace. Doing that once I >>> know the page numbers is fairly trivial, but what is the recommended way >>> of communicating one or more page numbers from domU to dom0, hopefully >>> without having to modify xend? >> >> >> >> Hrrrm. There was talk of a simple generic control message that could >> be used for this sort of thing but I''m not sure if it''s been implemented. > > > Sad. I tried sticking this at the last four bytes of the shared_info > page, but apparently that one gets cleared every now and then :-(Anyway, for now I guess I can just extend the shared_info_t struct and things should work, but in the longer run it might be nice to have some kind of simple mechanism for doing this stuff. Jacob ------------------------------------------------------- This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting Tool for open source databases. Create drag-&-drop reports. Save time by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. Download a FREE copy at http://www.intelliview.com/go/osdn_nl _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
> > Hrrrm. There was talk of a simple generic control message > that could be used > > for this sort of thing but I''m not sure if it''s been implemented. > > Sad. I tried sticking this at the last four bytes of the shared_info > page, but apparently that one gets cleared every now and then :-(The last half of the shared_info page is the control message ring, so this won''t work. Ian ------------------------------------------------------- This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting Tool for open source databases. Create drag-&-drop reports. Save time by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. Download a FREE copy at http://www.intelliview.com/go/osdn_nl _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
> I am mapping some pages in a domU from dom0 userspace. Doing that once I> know the page numbers is fairly trivial, but what is the recommended way> of communicating one or more page numbers from domU to dom0, hopefully > without having to modify xend?I am curious: I''m just starting to look into the mechanisms by which pages are shared between domains. The above question surprised me, because I''d assumed there existed some sort of anonymous "I want to map a page that domain N has exported" method to bootstrap direct interdomain communication between unprivileged domains. Looking through the code now, could someone please comment on the correctness (or, more importantly, uncorrectness) of the following statements? * It is possible for two unprivileged domains to share pages, without needing any intervention from a privileged domain, as long as each side knows in advance the addresses of the pages to be shared? * The grant_table_op hypervisor call is used by Domain-A to notify Xen that "yes, I want to allow Domain-B to map this page"? Then, the update_va_mapping hypervisor call is used by Domain-B to map the page? * grant_table_op cannot be used by Domain-A to revoke Domain-B''s mapping of the page? (I.e., all the "unmap grant ref" flag says is "cause all future Domain-B update_va_mapping calls, regarding mapping this page, to fail"?) * Jacob''s problem (dom0 needing to know the addresses of pages shared by a domU) is avoided during virtual network and virtual block device setup, because the pages to be shared are somehow either set up by Xen or shared through the "control interface" channel to Xend? Thanks, JLG ------------------------------------------------------- This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting Tool for open source databases. Create drag-&-drop reports. Save time by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. Download a FREE copy at http://www.intelliview.com/go/osdn_nl _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
> I am curious: I''m just starting to look into the mechanisms by which pages > are shared between domains. The above question surprised me, because I''d > assumed there existed some sort of anonymous "I want to map a page that > domain N has exported" method to bootstrap direct interdomain > communication between unprivileged domains.To map another domain''s memory you have to know the machine address of the page frame in question.> Looking through the code now, could someone please comment on the > correctness (or, more importantly, uncorrectness) of the following > statements?Here goes...> * It is possible for two unprivileged domains to share pages, without > needing any intervention from a privileged domain, as long as each side > knows in advance the addresses of the pages to be shared?Not yet. Grant tables should enable this but are not completed yet. For now, you need to be a privileged domain to map another domain''s memory.> * The grant_table_op hypervisor call is used by Domain-A to notify Xen > that "yes, I want to allow Domain-B to map this page"? Then, the > update_va_mapping hypervisor call is used by Domain-B to map the page?It will be, when the grant tables stuff is finished.> * grant_table_op cannot be used by Domain-A to revoke Domain-B''s mapping > of the page? (I.e., all the "unmap grant ref" flag says is "cause all > future Domain-B update_va_mapping calls, regarding mapping this page, to > fail"?)I think the plan is to enable domains to appeal to domain 0 if a mapping that should have been relinquished by another domain is not. Some sort of algorithm is then to be used by management code in domain 0 to decide what to do about it.> * Jacob''s problem (dom0 needing to know the addresses of pages shared by a > domU) is avoided during virtual network and virtual block device setup, > because the pages to be shared are somehow either set up by Xen or shared > through the "control interface" channel to Xend?The control interface protocols for each of the device interfaces include a message from the frontend that tells Xend where the shared memory frame for the device interface''s comms ring is placed (in machine addresses). Xend then sends this address to the backend so it knows where the interface ring is. Messages passed over a device interface ring contain machine addresses that the backend can use to map the actual IO destination Cheers, Mark ------------------------------------------------------- This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting Tool for open source databases. Create drag-&-drop reports. Save time by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. Download a FREE copy at http://www.intelliview.com/go/osdn_nl _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel