[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-devel] [PATCH][RESEND]Nvram patch for IA64
> >> Yes, static good configurations can be made for different guest OS > >> (RHEL, SLES, Win 2003, Win Vista). But I am afraid this workaround > >> will have potential issue, because we are unable to > predict how guest > >> OS would use variable. > > > > Is the variable contents the same for all installs of each > of the OSes > > you list? > > No, different OS has differrent configurations. But do all installs of the same OS have the same variable contents? That was the question. > >>> Further, storing it in a file will create compilcations > when we move > >>> to running qemu in stub domains -- we'll need a way of passing it > >>> across xenbus. > >> > >> Could you please elaborate what the "complications" is? Per my > >> understanding, even without NVRAM file, qemu in stub domain still > >> need to read/write the disk image file. > > > > You won't be able to write stuff to a file directly, you'll need to > > use a front/back driver, which is needlessly complicated. xenbus is > > definitely the way to go. > > > >> It is also OK to store NVRAM in xenstore, but seems > xenstore have no > >> capability to store binary data, it can only store > null-termincated > >> strings. If we want to directly store EFI variable in xenstore > >> instead of sotre NVRAM binary, we need to para-virtualize guest > >> firmware GetVariable/Setvariable interface, which is more > >> complicated. > > > > You'll have to escape the NULLs. It might be easiest just > to store the > > hex string. > > > > You don't need to paravirtulize it as qemu can do the trivial > > conversion. > > > > Ian > > OK. this should work. Then the only concern is the size of > NVRAM. 64KB data is quite large for xenstore. Is it > acceptable to xenstore? Maybe qemu need to compress the data > first. Usually, most of the NVRAM content is free area, which > is continuous byte "0xFF", so compresion can reduce the size > significantly. Break it into 64 byte (128 character) chunks and only populate nodes that are not all ones. Ian _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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