From: Jacob Pan <jacob.jun.pan@linux.intel.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
Alex Williamson <alex.williamson@redhat.com>,
Raj Ashok <ashok.raj@intel.com>,
David Woodhouse <dwmw2@infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
iommu@lists.linux-foundation.org,
Jean-Philippe Brucker <jean-philippe@linaro.com>,
Jonathan Cameron <jic23@kernel.org>
Subject: Re: [PATCH v13 3/8] iommu/vt-d: Add nested translation helper function
Date: Thu, 14 May 2020 08:31:43 -0700 [thread overview]
Message-ID: <20200514083143.6400d813@jacob-builder> (raw)
In-Reply-To: <20200514055424.GC22388@infradead.org>
On Wed, 13 May 2020 22:54:24 -0700
Christoph Hellwig <hch@infradead.org> wrote:
> > + * 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;
>
Sounds good. I was thinking in positive logic.
thanks
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next prev parent reply other threads:[~2020-05-14 15:25 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-13 23:01 [PATCH v13 0/8] Nested Shared Virtual Address (SVA) VT-d support Jacob Pan
2020-05-13 23:01 ` [PATCH v13 1/8] iommu/vt-d: Move domain helper to header Jacob Pan
2020-05-13 23:01 ` [PATCH v13 2/8] iommu/vt-d: Use a helper function to skip agaw for SL Jacob Pan
2020-05-14 5:51 ` Christoph Hellwig
2020-05-14 15:20 ` Jacob Pan
2020-05-13 23:01 ` [PATCH v13 3/8] iommu/vt-d: Add nested translation helper function Jacob Pan
2020-05-14 5:54 ` Christoph Hellwig
2020-05-14 15:31 ` Jacob Pan [this message]
2020-05-13 23:01 ` [PATCH v13 4/8] iommu/vt-d: Add bind guest PASID support Jacob Pan
2020-05-14 5:59 ` Christoph Hellwig
2020-05-14 15:57 ` Jacob Pan
2020-05-15 1:01 ` Lu Baolu
2020-05-16 6:02 ` Lu Baolu
2020-05-13 23:01 ` [PATCH v13 5/8] iommu/vt-d: Support flushing more translation cache types Jacob Pan
2020-05-13 23:01 ` [PATCH v13 6/8] iommu/vt-d: Add svm/sva invalidate function Jacob Pan
2020-05-13 23:01 ` [PATCH v13 7/8] iommu/vt-d: Enlightened PASID allocation Jacob Pan
2020-05-13 23:01 ` [PATCH v13 8/8] iommu/vt-d: Add custom allocator for IOASID Jacob Pan
2020-05-16 6:31 ` [PATCH v13 0/8] Nested Shared Virtual Address (SVA) VT-d support Lu Baolu
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