Add the oil to the liner of a 6- or 8-quart Instant Pot and set to SAUTE. Add the onion and cook until tender, about 6 minutes. Add the garlic and curry powder and cook 1 more minute. Add the squash, salt, and broth to the pot. Cover the Instant Pot with the lid and lock into place. Seal the steam release handle. Select HIGH PRESSURE and set the timer for 15 minutes. When the timer is up, let rest for 10 minutes, then manually release the pressure (unseal the steam release handle). Unlock and remove lid, being careful of any remaining steam. Meanwhile, pour the coconut milk into a blender. Blend until smooth. Pour into a bowl and set aside.  Transfer one-half of the squash mixture to a blender. Remove the top insert from the lid and cover with a kitchen towel. Puree until smooth, 30 seconds. Repeat with the second half of the soup. Return blended soup to pot. Stir in 1 cup of the coconut milk. Serve warm topped with a swirl of additional coconut milk, cilantro, and sliced jalapenos, if desired.