linux-kernel - Re: [PATCH v13 3/8] iommu/vt-d: Add nested translation helper function

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 13 May 2020 22:54:24 -0700
From:   Christoph Hellwig <hch@...radead.org>
To:     Jacob Pan <jacob.jun.pan@...ux.intel.com>
Cc:     Lu Baolu <baolu.lu@...ux.intel.com>,
        iommu@...ts.linux-foundation.org,
        LKML <linux-kernel@...r.kernel.org>,
        Joerg Roedel <joro@...tes.org>,
        David Woodhouse <dwmw2@...radead.org>,
        Jean-Philippe Brucker <jean-philippe@...aro.com>,
        Eric Auger <eric.auger@...hat.com>,
        Yi Liu <yi.l.liu@...el.com>,
        "Tian, Kevin" <kevin.tian@...el.com>,
        Raj Ashok <ashok.raj@...el.com>,
        Alex Williamson <alex.williamson@...hat.com>,
        Christoph Hellwig <hch@...radead.org>,
        Jonathan Cameron <jic23@...nel.org>
Subject: Re: [PATCH v13 3/8] iommu/vt-d: Add nested translation helper
 function

> +	 * 1. CPU vs. IOMMU
> +	 * 2. Guest vs. Host.
> +	 */
> +	switch (addr_width) {
> +#ifdef CONFIG_X86
> +	case ADDR_WIDTH_5LEVEL:
> +		if (cpu_feature_enabled(X86_FEATURE_LA57) &&
> +		    cap_5lp_support(iommu->cap)) {
> +			pasid_set_flpm(pte, 1);
> +		} else {
> +			dev_err_ratelimited(dev, "5-level paging not supported\n");
> +			return -EINVAL;
> +		}
> +		break;

The normal style would be to handle the early error return first:

		if (!cpu_feature_enabled(X86_FEATURE_LA57) ||
		    !cap_5lp_support(iommu->cap)) {
			dev_err_ratelimited(dev,
				"5-level paging not supported\n");
			return -EINVAL;
		}

		pasid_set_flpm(pte, 1);
		break;