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From: Jacob Pan <jacob.jun.pan@linux.intel.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Lu Baolu <baolu.lu@linux.intel.com>,
	iommu@lists.linux-foundation.org,
	LKML <linux-kernel@vger.kernel.org>,
	Joerg Roedel <joro@8bytes.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Jean-Philippe Brucker <jean-philippe@linaro.com>,
	Eric Auger <eric.auger@redhat.com>, Yi Liu <yi.l.liu@intel.com>,
	"Tian, Kevin" <kevin.tian@intel.com>,
	Raj Ashok <ashok.raj@intel.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Jonathan Cameron <jic23@kernel.org>,
	jacob.jun.pan@linux.intel.com
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

WARNING: multiple messages have this Message-ID (diff)
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
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  reply	other threads:[~2020-05-14 15:25 UTC|newest]

Thread overview: 37+ 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 ` 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   ` 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
2020-05-13 23:01   ` Jacob Pan
2020-05-14  5:51   ` Christoph Hellwig
2020-05-14  5:51     ` Christoph Hellwig
2020-05-14 15:20     ` Jacob Pan
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
2020-05-13 23:01   ` Jacob Pan
2020-05-14  5:54   ` Christoph Hellwig
2020-05-14  5:54     ` Christoph Hellwig
2020-05-14 15:31     ` Jacob Pan [this message]
2020-05-14 15:31       ` Jacob Pan
2020-05-13 23:01 ` [PATCH v13 4/8] iommu/vt-d: Add bind guest PASID support Jacob Pan
2020-05-13 23:01   ` Jacob Pan
2020-05-14  5:59   ` Christoph Hellwig
2020-05-14  5:59     ` Christoph Hellwig
2020-05-14 15:57     ` Jacob Pan
2020-05-14 15:57       ` Jacob Pan
2020-05-15  1:01       ` Lu Baolu
2020-05-15  1:01         ` Lu Baolu
2020-05-16  6:02       ` 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   ` 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   ` Jacob Pan
2020-05-13 23:01 ` [PATCH v13 7/8] iommu/vt-d: Enlightened PASID allocation Jacob Pan
2020-05-13 23:01   ` Jacob Pan
2020-05-13 23:01 ` [PATCH v13 8/8] iommu/vt-d: Add custom allocator for IOASID Jacob Pan
2020-05-13 23:01   ` Jacob Pan
2020-05-16  6:31 ` [PATCH v13 0/8] Nested Shared Virtual Address (SVA) VT-d support Lu Baolu
2020-05-16  6:31   ` Lu Baolu
2020-05-15 21:11 [PATCH v13 3/8] iommu/vt-d: Add nested translation helper function kbuild test robot

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