Re: [kvm-unit-tests v2 06/10] powerpc/sprs: Specify SPRs with data rather than code

On Thu Mar 23, 2023 at 10:36 PM AEST, Thomas Huth wrote:

On 20/03/2023 08.03, Nicholas Piggin wrote:

quoted

+/* SPRs common denominator back to PowerPC Operating Environment Architecture */
+static const struct spr sprs_common[1024] = {
+  [1] = {"XER",		64,	RW,		SPR_HARNESS, }, /* Compiler */
+  [8] = {"LR", 		64,	RW,		SPR_HARNESS, }, /* Compiler, mfspr/mtspr */
+  [9] = {"CTR",		64,	RW,		SPR_HARNESS, }, /* Compiler, mfspr/mtspr */
+ [18] = {"DSISR",	32,	OS_RW,		SPR_INT, },
+ [19] = {"DAR",		64,	OS_RW,		SPR_INT, },
+ [26] = {"SRR0",	64,	OS_RW,		SPR_INT, },
+ [27] = {"SRR1",	64,	OS_RW,		SPR_INT, },
+[268] = {"TB",		64,	RO	,	SPR_ASYNC, },
+[269] = {"TBU",		32,	RO,		SPR_ASYNC, },
+[272] = {"SPRG0",	64,	OS_RW,		SPR_HARNESS, }, /* Int stack */
+[273] = {"SPRG1",	64,	OS_RW,		SPR_HARNESS, }, /* Scratch */
+[274] = {"SPRG2",	64,	OS_RW, },
+[275] = {"SPRG3",	64,	OS_RW, },
+[287] = {"PVR",		32,	OS_RO, },
+};

Using a size of 1024 for each of these arrays looks weird. Why don't you add 
a "nr" field to struct spr and specify the register number via that field 
instead of using the index into the array as register number?

Oh I meant to reply to this. I did try it that way at first. When it
came manipulating the arrays like merging them or adding and
subtracing some SPRs, it required a bit of code to search, sort, add,
remove, etc. This way takes almost nothing. It is a dumb data structure
but it works okay here.

Thanks,
Nick