Re: [PATCH 5/5 V2] kvm tools: Initialize and use VESA and VNC

Ingo Molnar
2011-05-23T11:38:28Z

* Sasha Levin <levinsasha928@gmail.com> wrote:

> @@ -511,7 +515,13 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
> kvm->nrcpus = nrcpus;
>
> memset(real_cmdline, 0, sizeof(real_cmdline));
> - strcpy(real_cmdline, "notsc noapic noacpi pci=conf1 console=ttyS0 earlyprintk=serial");
> + strcpy(real_cmdline, "notsc noapic noacpi pci=conf1");
> + if (vnc) {
> + strcat(real_cmdline, " video=vesafb console=tty0");
> + vidmode = 0x312;
> + } else {
> + strcat(real_cmdline, " console=ttyS0 earlyprintk=serial");
> + }

Hm, i think all the kernel parameter handling code wants to move into driver
specific routines as well. Something like:

serial_init(kvm, real_cmdline);

where serial_init() would append to real_cmdline if needed.

This removes a bit of serial-driver specific knowledge from kvm-run.c.

Same goes for the VESA driver and the above video mode flag logic.

> @@ -597,6 +607,9 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
>
> kvm__init_ram(kvm);
>
> + if (vnc)
> + vesa__init(kvm);

Shouldnt vesa__init() itself know about whether it's active (i.e. the 'vnc'
flag is set) and return early if it's not set?

That way this could become more encapsulated and self-sufficient:

vesa__init(kvm);

With no VESA driver specific state exposed to the generic kvm_cmd_run()
function.

Ideally kvm_cmd_run() hould just be a series of:

serial_init(kvm, real_cmdline);
vesa_init(kvm, real_cmdline);
...

initialization routines. Later on even this could be removed: using section
tricks we can put init functions into a section and drivers could register
their init function like initcall(func) functions are registered within the
kernel. kvm_cmd_run() could thus iterate over that (build time constructed)
section like this:

extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[];

static void __init do_initcalls(void)
{
initcall_t *fn;

for (fn = __early_initcall_end; fn < __initcall_end; fn++)
do_one_initcall(*fn);
}

and would not actually have *any* knowledge about what drivers were built in.

Currently it's fine to initialize everything explicitly - but this would be the
long term model to work towards ...

Thanks,

Ingo