Hi all, I have a simple question about the device passthrough functionality, that Xen 3.3 started to support. Does the functionality provide direct I/O for "system volume" in guest domain? I suppose extension of many components, such as guest firmware, will be needed. Somebody have a plan to do the extension? Best regards, ----- Jun Kamada _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Samuel Thibault
2008-Aug-28 08:59 UTC
Re: [Xen-devel] Question: direct I/O for system volume
Hello, Jun Kamada, le Wed 27 Aug 2008 20:07:23 +0900, a écrit :> Does the functionality provide direct I/O for "system volume" in guest > domain?What do you call "system volume"? Samuel _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Hi Samuel-san, On Thu, 28 Aug 2008 09:59:08 +0100 Samuel Thibault <samuel.thibault@eu.citrix.com> wrote:> Jun Kamada, le Wed 27 Aug 2008 20:07:23 +0900, a 馗rit : > > Does the functionality provide direct I/O for "system volume" in guest > > domain? > > What do you call "system volume"?Sorry, it means "boot disk". Guest software can directly see HBA(Host Bus Adapter) as a hardware by using the device passthrough functionality. However, current guest BIOS doesn''t have a capability to load and invoke expansion ROM stored in the HBA, I guess. As a result, the guest OS cannot boot up from a disk under the HBA. #If my understanding was wrong, please point out. I understand that this limitation does not come from the device passthrough functionality, but probably from guest BIOS or the other component. Best regards, ----- Jun Kamada _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Samuel Thibault
2008-Aug-28 09:44 UTC
Re: [Xen-devel] Question: direct I/O for system volume
Hello, Jun Kamada, le Thu 28 Aug 2008 18:31:23 +0900, a écrit :> On Thu, 28 Aug 2008 09:59:08 +0100 > Samuel Thibault <samuel.thibault@eu.citrix.com> wrote: > > Jun Kamada, le Wed 27 Aug 2008 20:07:23 +0900, a 馗rit : > > > Does the functionality provide direct I/O for "system volume" in guest > > > domain? > > > > What do you call "system volume"? > > Sorry, it means "boot disk". > > Guest software can directly see HBA(Host Bus Adapter) as a hardware > by using the device passthrough functionality. However, current guest > BIOS doesn''t have a capability to load and invoke expansion ROM stored > in the HBA, I guess. As a result, the guest OS cannot boot up from a > disk under the HBA.Ok, much more clear :) You may want to have a look at Jean Guyader''s work on VGA card pass-through, which precisely requires mapping the expansion ROM into the guest. In other words, the tools to achieve it are there, I guess you just need to assemble them. Samuel _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Hi Samuel-san, Thank you for your helpful information. I will access the work. Best regards, On Thu, 28 Aug 2008 10:44:41 +0100 Samuel Thibault <samuel.thibault@eu.citrix.com> wrote:> Hello, > > Jun Kamada, le Thu 28 Aug 2008 18:31:23 +0900, a ecrit : > > On Thu, 28 Aug 2008 09:59:08 +0100 > > Samuel Thibault <samuel.thibault@eu.citrix.com> wrote: > > > Jun Kamada, le Wed 27 Aug 2008 20:07:23 +0900, a 馗rit : > > > > Does the functionality provide direct I/O for "system volume" in guest > > > > domain? > > > > > > What do you call "system volume"? > > > > Sorry, it means "boot disk". > > > > Guest software can directly see HBA(Host Bus Adapter) as a hardware > > by using the device passthrough functionality. However, current guest > > BIOS doesn''t have a capability to load and invoke expansion ROM stored > > in the HBA, I guess. As a result, the guest OS cannot boot up from a > > disk under the HBA. > > Ok, much more clear :) > You may want to have a look at Jean Guyader''s work on VGA card > pass-through, which precisely requires mapping the expansion ROM into > the guest. In other words, the tools to achieve it are there, I guess > you just need to assemble them. > > Samuel----- Jun Kamada _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel