* Dom0 IO handling @ 2012-10-11 6:16 maheen butt 2012-10-19 1:48 ` George Shuklin 0 siblings, 1 reply; 2+ messages in thread From: maheen butt @ 2012-10-11 6:16 UTC (permalink / raw) To: xen-users@lists.xen.org, xen-devel@lists.xensource.com [-- Attachment #1.1: Type: text/plain, Size: 466 bytes --] Hi all, I'm investigating the source code of Xenified kernel. From documentations related to Xen told me that all guest domains run in less privilege mode ( ring 1 in case of x86). Dom0 is also running in ring 1. But it can have direct access to IO devices. It means Dom0 has a special bahaviour that it is running in ring1 but can directly access IO devices. How Dom0 access IO devices directly? how can I relate this special way of Dom0 with its source code? [-- Attachment #1.2: Type: text/html, Size: 1595 bytes --] [-- Attachment #2: Type: text/plain, Size: 126 bytes --] _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel ^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: Dom0 IO handling 2012-10-11 6:16 Dom0 IO handling maheen butt @ 2012-10-19 1:48 ` George Shuklin 0 siblings, 0 replies; 2+ messages in thread From: George Shuklin @ 2012-10-19 1:48 UTC (permalink / raw) To: xen-devel [-- Attachment #1.1: Type: text/plain, Size: 949 bytes --] AFAIK dom0 is pv-domain. All interrupts are handled by xen and passed down to dom0 via events (kinda internal xen interrupt-like stuff). PV kernel accepts them and process as normal interrupts. Is Xen use IOMMU to protect itself from misbehave devices or not... I'm not sure. On 11.10.2012 10:16, maheen butt wrote: > Hi all, > > I'm investigating the source code of Xenified kernel. From > documentations related to > Xen told me that all guest domains run in less privilege mode ( ring 1 > in case of x86). > Dom0 is also running in ring 1. But it can have direct access to IO > devices. It means > Dom0 has a special bahaviour that it is running in ring1 but can > directly access IO devices. > How Dom0 access IO devices directly? > how can I relate this special way of Dom0 with its source code? > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel [-- Attachment #1.2: Type: text/html, Size: 2925 bytes --] [-- Attachment #2: Type: text/plain, Size: 126 bytes --] _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel ^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2012-10-19 1:48 UTC | newest] Thread overview: 2+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2012-10-11 6:16 Dom0 IO handling maheen butt 2012-10-19 1:48 ` George Shuklin
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