xvYCC has the same effective primaries as rec.709, but has a goofy wider gamut that is allowed by letting the Cb Cr coefficients use the 0-16, 240-255 that effectively create negative RGB values.
I wouldn't worry about calibrating for xvYCC, there are no patterns for correctly calibrating it. The gamut is not uniform (the maximum saturation is highly dependent on luminance). It's just a bit of an oddball. Good idea, not actual implementation of it.
The DCI spec uses the P3 gamut as a minimum requirement. Since it encodes color in XYZ technically it can encode all color.
red 0.680, 0.320
green 0.265, 0.690
blue 0.150, 0.060
white 0.314, 0.3509
CalMAN Lead Developer