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From: Jerry Snitselaar <jsnitsel@redhat.com>
To: Joerg Roedel <joro@8bytes.org>
Cc: Filippo Sironi <sironi@amazon.de>,
	iommu@lists.linux-foundation.org, jroedel@suse.de
Subject: Re: [PATCH 4/6] iommu/amd: Check for busy devices earlier in attach_device()
Date: Wed, 25 Sep 2019 23:37:01 -0700
Message-ID: <20190926063701.drppvoo6nztxtbjq@cantor> (raw)
In-Reply-To: <20190925132300.3038-5-joro@8bytes.org>

On Wed Sep 25 19, Joerg Roedel 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
>
>_______________________________________________
>iommu mailing list
>iommu@lists.linux-foundation.org
>https://lists.linuxfoundation.org/mailman/listinfo/iommu

Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  parent reply index

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
2019-09-26  6:37   ` Jerry Snitselaar [this message]
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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