Re: [PATCH v2.2 07/15] xen: generate hypercall interface related code

[Jan Beulich <jbeulich@xxxxxxxx>]

On 03.11.2021 11:20, Juergen Gross wrote:
> Instead of repeating similar data multiple times use a single source
> file and a generator script for producing prototypes and call sequences
> of the hypercalls.
> 
> As the script already knows the number of parameters used add generating
> a macro for populating an array with the number of parameters per
> hypercall.
> 
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>

What's missing here now that you have introduced priorities is how you
did arrive at the chosen values. That's a pretty important aspect,
especially if someone would later want to adjust these.

Just one further remark from looking at the output of the script (thanks
for making that available):

> +# Generate the output
> +END {
> +    # Verbatim generated lines
> +    for (i = 1; i <= e; i++)
> +        printf("%s\n", emit[i]);
> +    printf("\n");
> +    # Generate prototypes
> +    for (i = 1; i <= n; i++) {
> +        for (p = 1; p <= n_pre[i]; p++) {
> +            printf("%s %s_%s(", rettype[pre[i, p]], pre[i, p], fn[i]);
> +            if (n_args[i] == 0)
> +                printf("void");
> +            else
> +                for (j = 1; j <= n_args[i]; j++) {
> +                    if (j > 1)
> +                        printf(", ");
> +                    if (ptr[i, j])
> +                        printf("XEN_GUEST_HANDLE_PARAM(%s)", typ[i, j]);
> +                    else
> +                        printf("%s", typ[i, j]);
> +                    printf(" %s", arg[i, j]);
> +                }
> +            printf(");\n");
> +        }
> +    }
> +    # Generate call sequences and args array contents
> +    for (ca in caller) {
> +        if (caller[ca] != 1)
> +            continue;
> +        need_mask = 0;
> +        for (pl = 1; pl <= n_prios[ca]; pl++) {
> +            for (pll = pl; pll > 1; pll--) {
> +                if (prio_list[ca, pl] > p_list[pll - 1])
> +                    break;
> +                else
> +                    p_list[pll] = p_list[pll - 1];
> +            }
> +            p_list[pll] = prio_list[ca, pl];
> +            # If any prio but the default one has more than 1 entry we need 
> "mask"
> +            if (p_list[pll] != 100 && prios[ca, p_list[pll]] > 1)
> +                need_mask = 1;
> +        }
> +        printf("\n");
> +        printf("#define call_handlers_%s(num, ret, a1, a2, a3, a4, a5) 
> \\\n", ca);
> +        printf("{ \\\n");
> +        if (need_mask)
> +            printf("    uint64_t mask = 1ULL << num; \\\n");
> +        printf("    ");
> +        for (pl = 1; pl <= n_prios[ca]; pl++) {
> +            if (prios[ca, p_list[pl]] > 1) {
> +                if (pl < n_prios[ca]) {
> +                    printf("if ( likely(mask & (%s)) ) \\\n", prio_mask[ca, 
> p_list[pl]]);
> +                    printf("    { \\\n");
> +                }
> +                if (prios[ca, p_list[pl]] == 2) {
> +                    fnd = 0;
> +                    for (i = 1; i <= nc; i++)
> +                        if (call[i] == ca && call_prio[i] == p_list[pl]) {
> +                            fnd++;
> +                            if (fnd == 1)
> +                                printf("        if ( num == __HYPERVISOR_%s 
> ) \\\n", fn[call_fn[i]]);
> +                            else
> +                                printf("        else \\\n");
> +                            do_call(call_fn[i], call_p[i]);
> +                        }
> +                } else {
> +                    do_switch(ca, p_list[pl]);
> +                }
> +                if (pl < n_prios[ca])
> +                    printf("    } \\\n");
> +            } else {
> +                for (i = 1; i <= nc; i++)
> +                    if (call[i] == ca && call_prio[i] == p_list[pl]) {
> +                        printf("if ( likely(num == __HYPERVISOR_%s) ) \\\n", 
> fn[call_fn[i]]);
> +                        do_call(call_fn[i], call_p[i]);
> +                    }
> +            }
> +            if (pl < n_prios[ca] || prios[ca, p_list[pl]] <= 2)
> +                printf("    else ");

I think there's a line continuation escape + newline missing here.

Jan