[PATCH] drm/i915/gvt: Add gvt_debug to classify GVT-g log messages

[Zhenyu Wang]

On 2017.08.31 20:41:00 +0800, Liu Shuo wrote:
> > > diff --git a/drivers/gpu/drm/i915/gvt/Makefile b/drivers/gpu/drm/i915/gvt/Makefile
> > > index f5486cb9..2b5955a 100644
> > > --- a/drivers/gpu/drm/i915/gvt/Makefile
> > > +++ b/drivers/gpu/drm/i915/gvt/Makefile
> > > @@ -6,3 +6,4 @@ GVT_SOURCE := gvt.o aperture_gm.o handlers.o vgpu.o trace_points.o firmware.o \
> > >  ccflags-y				+= -I$(src) -I$(src)/$(GVT_DIR)
> > >  i915-y					+= $(addprefix $(GVT_DIR)/, $(GVT_SOURCE))
> > >  obj-$(CONFIG_DRM_I915_GVT_KVMGT)	+= $(GVT_DIR)/kvmgt.o
> > > +obj-$(CONFIG_DRM_I915_GVT_DEBUG)	+= $(GVT_DIR)/gvt_debug.o
> > 
> > Let's align file naming, just use "debug.c".
> Changing name is just for the output module. gvt_debug.ko is more easy
> to understand.

oh, no, don't like for extra module, not necessary, debug.c should be in GVT_SOURCE
if debug option is on.

> > > diff --git a/drivers/gpu/drm/i915/gvt/gvt_debug.c b/drivers/gpu/drm/i915/gvt/gvt_debug.c
> > > new file mode 100644
> > > index 0000000..8fe8b2f
> > > --- /dev/null
> > > +++ b/drivers/gpu/drm/i915/gvt/gvt_debug.c
> > > @@ -0,0 +1,41 @@
> > > +#include <linux/module.h>
> > > +#include "debug.h"
> > > +
> > > +static unsigned int gvt_debug;
> > > +
> > > +module_param_named(debug, gvt_debug, int, 0600);
> > > +MODULE_PARM_DESC(debug, "Enable Gvt-g debug output, where each bit enables a category.\n"
> > > +		"\t\tBit 0 (0x01) will enable CORE messages (GVT-g core message)\n"
> > > +		"\t\tBit 1 (0x02) will enable IRQ messages (GVT-g interrupt message)\n"
> > > +		"\t\tBit 2 (0x04) will enable MM messages (GVT-g memory management message)\n"
> > > +		"\t\tBit 3 (0x08) will enable MMIO messages (GVT-g MMIO message)\n"
> > > +		"\t\tBit 4 (0x10) will enable DPY messages (GVT-g display message)\n"
> > > +		"\t\tBit 5 (0x20) will enable EL messages (GVT-g execlist message)\n"
> > > +		"\t\tBit 6 (0x40) will enable SCHED messages (GVT-g schedule message)\n"
> > > +		"\t\tBit 7 (0x80) will enable RENDER messages (GVT-g render message)\n"
> > > +		"\t\tBit 8 (0x100) will enable CMD messages (GVT-g command message)");
> > > +
> > > +void gvt_printk(const char *level, unsigned int category,
> > > +		const char *format, ...)
> > > +{
> > > +	struct va_format vaf;
> > > +	va_list args;
> > > +
> > > +	if (category != GVT_MSG_NONE && !(gvt_debug & category))
> > > +		return;
> > > +
> > > +	va_start(args, format);
> > > +	vaf.fmt = format;
> > > +	vaf.va = &args;
> > > +
> > > +	printk("%s[gvt:%ps]%s %pV",
> > > +		level, __builtin_return_address(0),
> > > +		strcmp(level, KERN_ERR) == 0 ? " *ERROR*" : "", &vaf);
> > > +
> > > +	va_end(args);
> > > +}
> > > +EXPORT_SYMBOL_GPL(gvt_printk);
> > 
> > Not required for other module, this is only for gvt internal usage.
> Fully agree with you to build it in gvt module.
> But here is limitation:
> 1) gvt in i915 module, while MPT in another module kvmgt 2) i915 module with
> gvt code has dependency on kvmgt
> 3) both i915 module with gvt and kvmgt has dependency on gvt_printk
> If we build gvt_printk into i915, it will deadlock while i915 modprobe.
> Any comments on this?

I don't think 2) is true and yes for 3), so you can export gvt_printk
for kvmgt module and use same debug.h for it. You can just add gvt_debug
option in i915 param.

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