Hi,everyone. I have some questions. 1. Does hvmoader need EPT for address translation when it is running? 2. I am sure the guest kernel need EPT when running, but not sure whether hvmloader also needs. I think when virtual bios in hvmloader running, we should make virtual bios sees as if the memory starting from 0, so hvmloader needs EPT, am I right? 3. If hvmloader needs EPT, where we construct EPT structure for it? I can''t find correlative part in code flow. Any helps? -- View this message in context: http://xen.1045712.n5.nabble.com/Question-about-EPT-translation-tp4432564p4432564.html Sent from the Xen - Dev mailing list archive at Nabble.com. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Hello, Next time I will only replay through the list. CC the list 2011/5/29 henanwxr <henanwxr@hotmail.com>:> Hi Daniel, I have post my questions on xen-devel but nobody reply. So I turn > to you for help. > 1. Does hvmoader need EPT for address translation when it is running?If you are talking to pure HVM Guest then yes.> 2. I am sure the guest kernel need EPT when running, but not sure whether > hvmloader also needs. I think when virtual bios in hvmloader running, we > should make virtual bios sees as if the memory starting from 0, so hvmloader > needs EPT, am I right?Yes> 3. If hvmloader needs EPT, where we construct EPT structure for it? I can''t > find correlative part in code flow.The address translation is not done by hvmloader, hvmloader is only used to deploy data to memory, the translation is done via Hypervisor aided by hardware. -- +-=====---------------------------+ | +---------------------------------+ | This space intentionally blank for notetaking. | | | Daniel Castro, | | | | Consultant/Programmer.| | | | U Andes | +-------------------------------------+ _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Hi, At 09:17 -0700 on 27 May (1306487843), confucius wrote:> Hi,everyone. I have some questions. > 1. Does hvmoader need EPT for address translation when it is running?_All_ HVM guests need _either_ EPT/NPT _or_ shadow pagetables, to make the extra translation from guest physical addresses to machine addresses.> 3. If hvmloader needs EPT, where we construct EPT structure for it? I can''t > find correlative part in code flow.Did you try searching the code for "EPT"? The EPT datastructures are construced in p2m_ept.c. (p2m is the general term in Xen for the table that maps physical addresses to machine addresses). Tim. -- Tim Deegan <tjd@phlegethon.org> We were back to the sad age-old knowledge that there are only two genuine aphrodisiacs: youth and boredom. [ Alistair Cooke, "Letter From America", 12/5/98 ] _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On Sun, 2011-05-29 at 22:49 +0100, Daniel Castro wrote:> Hello, > Next time I will only replay through the list. CC the list > > 2011/5/29 henanwxr <henanwxr@hotmail.com>: > > Hi Daniel, I have post my questions on xen-devel but nobody reply. So I turn > > to you for help.I also received private mail from this poster with pretty much identical content. I replied privately at length on the inappropriateness of this sort of behaviour but just to be extra clear: henanwxr -- it is not ever appropriate to scatter-shot private mails to people when you do not get an immediate reply to a list posting. I recommend that people who receive such emails either ignore them or ask them to be reposted on the list before replying, so as not to encourage this way of thinking. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On Sun, 2011-05-29 at 22:49 +0100, Daniel Castro wrote:> 2011/5/29 henanwxr <henanwxr@hotmail.com>: > > 1. Does hvmoader need EPT for address translation when it is running? > If you are talking to pure HVM Guest then yes.It doesn''t have to be EPT (which is the name of an Intel specific hardware technology). hvmloader needs some sort of page table translation, which might be HAP (the generic name for both Intel''s EPT and AMD''s nested paging) or shadow page tables depending on the hardware capabilities your system has.> > 2. I am sure the guest kernel need EPT when running, but not sure whether > > hvmloader also needs. I think when virtual bios in hvmloader running, we > > should make virtual bios sees as if the memory starting from 0, so hvmloader > > needs EPT, am I right? > YesAgain, correct modulo the above. hvmloader runs in the guest''s context and hence needs everything the guest kernel will need. Actually in the case of hvmloader "needs" is rather a strong word, "runs in that environment by design" would perhaps be more accurate.> > 3. If hvmloader needs EPT, where we construct EPT structure for it? I can''t > > find correlative part in code flow. > The address translation is not done by hvmloader, hvmloader is only > used to deploy data to memory, the translation is done via Hypervisor > aided by hardware.Ian. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel