On Jan 25, 2007, at 3:51 PM, Ryan Harper wrote:
* Jimi Xenidis <jimix@xxxxxxxxxxxxxx> [2007-01-25 14:40]:
Since you later look for the console_mfn and store_mfn later, it
would be better in the caller and pass then in.
FYI: It is xend that decides where store and console go.
shared_info
is a hypervisor contract so you can continue to calculate it
here if
you want.
Also the devtree should not contain MFNs for frame numbers of any
kind, simply addresses.
I don't follow. the start_info_t structure explicitly wants an
mfn, how
else am I suppose to fill that value out in linux?
they are MFNs on x86, in PPC they are domain physical addresses.
Maybe I've just got it named funny, I don't know. And I'm still
confused as to what you want me to put in?
I'm suggesting that we do not use a frame number in the devtree but
use the address that the frame number represents.
On PPC, MFN is a misnomer, this value is not an MFN but a domain PFN
(that is the page belongs to the domain), its just a bad name for us
because the structure is for x86. Later (on PPC) we convert the
domain PFN to and phys addr.
The value that I put in start_info->console.domU.mfn is:
((rma_pages << 12) - (2*PAGE_SIZE)) >> PAGE_SHIFT
where rma_pages = (1 << 26) >> PAGE_SHIFT
the resulting value is 0x3ffe. Is this value correct and I just
have an
incorrect name for it (mfn)?
yes
Am I getting lucky? I've tested the
patches and dom0 and domU boot.
Not luck, we just preserved a crappy name for a crappy struct that in
PPC land will dissapear.
{
struct boot_param_header *bph = NULL;
uint64_t val[2];
uint32_t val32[2];
unsigned long remaining;
- unsigned long rma_reserve = 4 * PAGE_SIZE;
+ unsigned long rma_reserve = 3 * PAGE_SIZE;
base this on MIN(store, console)
Why? Don't we always have a store and a console page?
yes we do, but they could be in any order, all you are trying to do
is make sure the pages are in the reserve map. Another possibility
is you could not assume contiguity and create a reservation entry for
each of the three pages.
I don't understand what is wrong with the above. We are reserving the
last X pages of the RMA. 1 for shared_info, 1 for console, one for
store. I futher don't understand what the value MIN(store,console)
gives me. Sorry for being dense here.
I know it is confusing, thats why it is so important we get it right.
First, I suggested that you pass in these addresses.
Once they are passed in, this function has no idea which one has the
lowest address.
There is nothing from stoping from changing the order of these 2
pages, as long as both sides agree.
-JX
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