I don't feel any BIOS patch will ever "fix" the problem because the problem is hard coded into the design of the processors. Patches may mitigate or even totally negate the vulnerabilities. But is a permanent patch a "fix"? I don't believe so in this case because it does not return everything back to "good as new" - or preferably better than new.
It is completely possible for this to be patched by BIOS. See, there's this little buffer, and it allows data inside it to be truncticated so that it fits more data than it would be allowed to otherwise. This allows for partial bits of code to be maligned from what YOU want, and allows an attacker to force their data to be used instead of the legit data. The fix (and why AMD is less prone to the problem) is to ensure that the data in this buffer is NOT truncticated (which AMD does already).
Of course, if this data takes up more space in the buffer, it slows things down a bit since more data is processed, and not as many commands can be held within the buffer. Bingo! Performance loss.
Think of a game cheat (trainer) injecting it's own code into a game. Similar thing here. Game thinks it's data is it's own, processes it, but instead of 100 life, you've got 10000.
We're talking about 1's and 0's here, not magic.
So sure, you can say "but I lost performance", but in reality, you didn't. The CPU is still performing as it should, and is processing data in the same way, it's just that it has to process a bit more now.
This really isn't as big of an issue as it seems to be, honestly. Security-wise, sure, it's a problem. But this problem has existed for a long time, and just because nobody knew it was being exploited does not mean that it hasn't been... I mean, the way I see it, this is part of why any system, be it Intel, AMD, ARM, or whatever, and any processor, whether it be in your PC or your phone, or your TV could and can be hacked for decades. These things do and can exist, and so I find myself asking WHY this is being presented as such a large issue... maybe you should ask yourself the same too.