terrafromでaws acm作成 cloudfrontの場合バージニアで作成しないといけないんだけどどうやるの？

providerの設定を変更したものを用意して、aliasを使うことで解決

provider "aws" {}

provider "aws" {
  alias  = "virginia"
  region = "us-east-1"
}

# 証明書発行リクエスト
resource "aws_acm_certificate" "cert" {
  domain_name       = "${lookup(var.domain_name, "${terraform.workspace}.value")}"
  validation_method = "DNS"
  provider          = "aws.virginia"

  lifecycle {
    create_before_destroy = true
  }
}

# DNSによる検証用レコードの登録
resource "aws_route53_record" "cert_validation" {
  name    = "${aws_acm_certificate.cert.domain_validation_options.0.resource_record_name}"
  type    = "${aws_acm_certificate.cert.domain_validation_options.0.resource_record_type}"
  zone_id = "${aws_route53_zone.xxxxxx.zone_id}"
  records = ["${aws_acm_certificate.cert.domain_validation_options.0.resource_record_value}"]
  ttl     = 60
}

# 検証
resource "aws_acm_certificate_validation" "cert" {
  certificate_arn         = "${aws_acm_certificate.cert.arn}"
  validation_record_fqdns = ["${aws_route53_record.cert_validation.fqdn}"]
  provider                = "aws.virginia"
}

resource "aws_cloudfront_distribution" "xxxxxx" {

  # ~~略~~

  viewer_certificate {
    acm_certificate_arn      = "${aws_acm_certificate.cert.arn}"
    ssl_support_method       = "sni-only"
    minimum_protocol_version = "TLSv1"
  }

  # ~~略~~

}

参考URL

amazon web services - How to specify a ACM certificate in a specific region for a data source? - Stack Overflow
TerraformによるAWS Certificate Manager(ACM)からの証明書取得とドメイン検証 - Qiita