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From: "Sironi, Filippo via iommu" <iommu@lists.linux-foundation.org>
To: Joerg Roedel <joro@8bytes.org>
Cc: "iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	"jroedel@suse.de" <jroedel@suse.de>
Subject: Re: [PATCH 4/6] iommu/amd: Check for busy devices earlier in attach_device()
Date: Wed, 25 Sep 2019 15:55:21 +0000	[thread overview]
Message-ID: <7FD56923-E57D-43BE-80FB-31D49A6D4D4A@amazon.de> (raw)
In-Reply-To: <20190925132300.3038-5-joro@8bytes.org>



> On 25. Sep 2019, at 06:22, Joerg Roedel <joro@8bytes.org> wrote:
> 
> From: Joerg Roedel <jroedel@suse.de>
> 
> Check early in attach_device whether the device is already attached to a
> domain. This also simplifies the code path so that __attach_device() can
> be removed.
> 
> Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
> Signed-off-by: Joerg Roedel <jroedel@suse.de>
> ---
> drivers/iommu/amd_iommu.c | 25 +++++++------------------
> 1 file changed, 7 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> index 2919168577ff..459247c32dc0 100644
> --- a/drivers/iommu/amd_iommu.c
> +++ b/drivers/iommu/amd_iommu.c
> @@ -2072,23 +2072,6 @@ static void do_detach(struct iommu_dev_data *dev_data)
> 	domain->dev_cnt                 -= 1;
> }
> 
> -/*
> - * If a device is not yet associated with a domain, this function makes the
> - * device visible in the domain
> - */
> -static int __attach_device(struct iommu_dev_data *dev_data,
> -			   struct protection_domain *domain)
> -{
> -	if (dev_data->domain != NULL)
> -		return -EBUSY;
> -
> -	/* Attach alias group root */
> -	do_attach(dev_data, domain);
> -
> -	return 0;
> -}
> -
> -
> static void pdev_iommuv2_disable(struct pci_dev *pdev)
> {
> 	pci_disable_ats(pdev);
> @@ -2174,6 +2157,10 @@ static int attach_device(struct device *dev,
> 
> 	dev_data = get_dev_data(dev);
> 
> +	ret = -EBUSY;
> +	if (dev_data->domain != NULL)
> +		goto out;
> +
> 	if (!dev_is_pci(dev))
> 		goto skip_ats_check;
> 
> @@ -2198,7 +2185,9 @@ static int attach_device(struct device *dev,
> 	}
> 
> skip_ats_check:
> -	ret = __attach_device(dev_data, domain);
> +	ret = 0;
> +
> +	do_attach(dev_data, domain);
> 
> 	/*
> 	 * We might boot into a crash-kernel here. The crashed kernel
> -- 
> 2.17.1
> 

Reviewed-by: Filippo Sironi <sironi@amazon.de>



Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Ralf Herbrich
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879



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  reply	other threads:[~2019-09-25 15:56 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-25 13:22 [PATCH 0/6] iommu/amd: Locking Fixes Joerg Roedel
2019-09-25 13:22 ` [PATCH 1/6] iommu/amd: Remove domain->updated Joerg Roedel
2019-09-25 15:45   ` Sironi, Filippo via iommu
2019-09-26  6:18   ` Jerry Snitselaar
2019-09-25 13:22 ` [PATCH 2/6] iommu/amd: Remove amd_iommu_devtable_lock Joerg Roedel
2019-09-25 15:50   ` Sironi, Filippo via iommu
2019-09-25 15:52     ` Sironi, Filippo via iommu
2019-09-26  6:24   ` Jerry Snitselaar
2019-09-25 13:22 ` [PATCH 3/6] iommu/amd: Take domain->lock for complete attach/detach path Joerg Roedel
2019-09-25 15:53   ` Sironi, Filippo via iommu
2019-09-26  6:34   ` Jerry Snitselaar
2019-09-25 13:22 ` [PATCH 4/6] iommu/amd: Check for busy devices earlier in attach_device() Joerg Roedel
2019-09-25 15:55   ` Sironi, Filippo via iommu [this message]
2019-09-26  6:37   ` Jerry Snitselaar
2019-09-25 13:22 ` [PATCH 5/6] iommu/amd: Lock dev_data in attach/detach code paths Joerg Roedel
2019-09-25 15:56   ` Sironi, Filippo via iommu
2019-09-26  6:41   ` Jerry Snitselaar
2019-09-25 13:23 ` [PATCH 6/6] iommu/amd: Lock code paths traversing protection_domain->dev_list Joerg Roedel
2019-09-25 15:58   ` Sironi, Filippo via iommu
2019-09-26  6:48   ` Jerry Snitselaar
2019-09-26  0:25 ` [PATCH 0/6] iommu/amd: Locking Fixes Jerry Snitselaar
2019-09-26  5:46   ` Joerg Roedel

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