Re: [PATCH v1.1 1/2] x86/sev: Use per-CPU PSC structure in prep for unaccepted memory support
From: Tom Lendacky
Date: Wed Aug 03 2022 - 17:03:46 EST
On 8/3/22 13:24, Dave Hansen wrote:
On 8/3/22 11:21, Tom Lendacky wrote:
Would it be simpler to just do a spin_trylock_irqsave()? You fall back
to early_set_pages_state() whenever you can't acquire the lock.
I was looking at that and can definitely go that route if this approach
is preferred.
I prefer it for sure.
This whole iteration does look good to me versus the per-cpu version, so
I say go ahead with doing this for v2 once you wait a bit for any more
feedback.
I'm still concerned about the whole spinlock and performance. What if I
reduce the number of entries in the PSC structure to, say, 64, which
reduces the size of the struct to 520 bytes. Any issue if that is put on
the stack, instead? It definitely makes things less complicated and feels
like a good compromise on the size vs the number of PSC VMGEXIT requests.
Thanks,
Tom