Re: [PATCH v12 17/29] KVM: SEV: Add support to handle RMP nested page faults

[Paolo Bonzini]

On 3/29/24 23:58, Michael Roth wrote:
> +	if (rmp_level == PG_LEVEL_4K) {
> +		pr_debug_ratelimited("%s: Spurious RMP fault for GPA 0x%llx, error_code 0x%llx",
> +				     __func__, gpa, error_code);
> +		goto out;
> +	}
> +
> +	pr_debug_ratelimited("%s: Splitting 2M RMP entry for GPA 0x%llx, error_code 0x%llx",
> +			     __func__, gpa, error_code);
> +	ret = snp_rmptable_psmash(pfn);
> +	if (ret && ret != PSMASH_FAIL_INUSE) {
> +		/*
> +		 * Look it up again. If it's 4K now then the PSMASH may have raced with
> +		 * another process and the issue has already resolved itself.
> +		 */
> +		if (!snp_lookup_rmpentry(pfn, &assigned, &rmp_level) && assigned &&
> +		    rmp_level == PG_LEVEL_4K) {
> +			pr_debug_ratelimited("%s: PSMASH for GPA 0x%llx failed with ret %d due to potential race",
> +					     __func__, gpa, ret);
> +			goto out;
> +		}

Please change these pr_debug_ratelimited() to just a single trace point 
after the call to snp_rmptable_psmash().

Paolo