On 07/07/2015 09:35 PM, Thomas Huth wrote:
On Tue, 7 Jul 2015 20:43:44 +1000
Alexey Kardashevskiy <a...@ozlabs.ru> wrote:
On 07/07/2015 07:33 PM, Thomas Huth wrote:
On Mon, 6 Jul 2015 12:11:10 +1000
Alexey Kardashevskiy <a...@ozlabs.ru> wrote:
...
+static void rtas_ibm_create_pe_dma_window(PowerPCCPU *cpu,
+ sPAPRMachineState *spapr,
+ uint32_t token, uint32_t nargs,
+ target_ulong args,
+ uint32_t nret, target_ulong rets)
+{
+ sPAPRPHBState *sphb;
+ sPAPRTCETable *tcet = NULL;
+ uint32_t addr, page_shift, window_shift, liobn;
+ uint64_t buid;
+ long ret;
+
+ if ((nargs != 5) || (nret != 4)) {
Pascal bracket style again :-(
Am I breaking any code design guideline here?
No, but my Pascal allergy causes me to sneeze here ;-)
I feel cold when I do not see braces in cases like this ;)
+ goto param_error_exit;
+ }
+
+ buid = ((uint64_t)rtas_ld(args, 1) << 32) | rtas_ld(args, 2);
But here braces are ok? :-/
You could remove them, too. But I did not need to sneeze here.
:)
+ addr = rtas_ld(args, 0);
+ sphb = spapr_pci_find_phb(spapr, buid);
+ if (!sphb || !sphb->ddw_enabled) {
+ goto param_error_exit;
+ }
+
+ page_shift = rtas_ld(args, 3);
+ window_shift = rtas_ld(args, 4);
+ liobn = spapr_phb_get_free_liobn(sphb);
+
+ if (!liobn || !(sphb->page_size_mask & (1ULL << page_shift))) {
+ goto hw_error_exit;
+ }
+
+ ret = spapr_phb_dma_init_window(sphb, liobn, page_shift,
+ 1ULL << window_shift);
As already mentioned in a comment to another patch in this series, I
think it maybe might be better to do some sanity checks on the
window_shift value, too?
Well, as you suggested, I added a check to spapr_phb_dma_init_window()
which makes this code return RTAS_OUT_HW_ERROR. Or I can add this here:
if (window_shift < page_shift) {
goto param_error_exit;
}
and RTAS handler will return RTAS_OUT_PARAM_ERROR.
SPAPR does not say what is the correct reponse in this case...
Both error codes sound ok for me here, so do whatever you think is best.
RTAS_OUT_PARAM_ERROR it is then.
+
+ rtas_st(rets, 0, RTAS_OUT_SUCCESS);
+ rtas_st(rets, 1, liobn);
+ rtas_st(rets, 2, tcet->bus_offset >> 32);
+ rtas_st(rets, 3, tcet->bus_offset & ((uint32_t) -1));
Why don't you simply use 0xffffffff instead of ((uint32_t) -1) ?
That's shorter and much easier to understand at a first glance than
calulating the type-cast in your brain ;-)
At a first glance I cannot tell if there are 7 or 8 or 9 "f"s in
0xffffffff. I may accidentally add/remove one "f" and nobody will notice.
Such typecast of (-1) is quite typical.
But IMHO it's ugly to use it to mask a value to the lower 32 bits this
way. At least I had to read this twice to understand what you're
trying to achieve here. So if you don't like the 0xffffffff, what about
simply using:
rtas_st(rets, 3, (uint32_t)tcet->bus_offset);
?
I believe there are compilers which will warn me than I am loosing upper
32bits.
--
Alexey
