From: "joro@8bytes.org" <joro@8bytes.org>
To: "Suthikulpanit, Suravee" <Suravee.Suthikulpanit@amd.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
"Singh, Brijesh" <brijesh.singh@amd.com>
Subject: Re: [PATCH] iommu/amd: Fix IOMMU page flush when detach all devices from a domain
Date: Wed, 16 Jan 2019 14:26:48 +0100 [thread overview]
Message-ID: <20190116132648.i5n3hz3k7d2wxbrx@8bytes.org> (raw)
In-Reply-To: <20190116041546.3541-1-Suravee.Suthikulpanit@amd.com>
On Wed, Jan 16, 2019 at 04:16:25AM +0000, Suthikulpanit, Suravee wrote:
> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> index 525659b88ade..ab31ba75da1b 100644
> --- a/drivers/iommu/amd_iommu.c
> +++ b/drivers/iommu/amd_iommu.c
> @@ -1248,7 +1248,13 @@ static void __domain_flush_pages(struct protection_domain *domain,
> build_inv_iommu_pages(&cmd, address, size, domain->id, pde);
>
> for (i = 0; i < amd_iommu_get_num_iommus(); ++i) {
> - if (!domain->dev_iommu[i])
> + /*
> + * The dev_cnt is zero when all devices are detached
> + * from the domain. This is the case when VFIO detaches
> + * all devices from the group before flushing IOMMU pages.
> + * So, always issue the flush command.
> + */
> + if (domain->dev_cnt && !domain->dev_iommu[i])
> continue;
This doesn't look like the correct fix. We still miss the flush if we
detach the last device from the domain. How about the attached diff? If
I understand the problem correctly, it should fix the problem more
reliably.
Thanks,
Joerg
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 87ba23a75b38..dc1e2a8a19d7 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -1991,25 +1991,36 @@ static void do_attach(struct iommu_dev_data *dev_data,
static void do_detach(struct iommu_dev_data *dev_data)
{
+ struct protection_domain *domain = dev_data->domain;
struct amd_iommu *iommu;
u16 alias;
iommu = amd_iommu_rlookup_table[dev_data->devid];
alias = dev_data->alias;
- /* decrease reference counters */
- dev_data->domain->dev_iommu[iommu->index] -= 1;
- dev_data->domain->dev_cnt -= 1;
-
/* Update data structures */
dev_data->domain = NULL;
list_del(&dev_data->list);
- clear_dte_entry(dev_data->devid);
- if (alias != dev_data->devid)
- clear_dte_entry(alias);
+ clear_dte_entry(dev_data->devid);
/* Flush the DTE entry */
device_flush_dte(dev_data);
+
+ if (alias != dev_data->devid) {
+ clear_dte_entry(alias);
+ /* Flush the Alias DTE entry */
+ device_flush_dte(alias);
+ }
+
+ /* Flush IOTLB */
+ domain_flush_tlb_pde(domain);
+
+ /* Wait for the flushes to finish */
+ domain_flush_complete(domain);
+
+ /* decrease reference counters - needs to happen after the flushes */
+ domain->dev_iommu[iommu->index] -= 1;
+ domain->dev_cnt -= 1;
}
/*
next prev parent reply other threads:[~2019-01-16 13:26 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-16 4:16 [PATCH] iommu/amd: Fix IOMMU page flush when detach all devices from a domain Suthikulpanit, Suravee
2019-01-16 13:26 ` joro [this message]
2019-01-16 14:08 ` Suthikulpanit, Suravee
2019-01-16 17:08 ` joro
2019-01-17 8:44 ` Suthikulpanit, Suravee
2019-01-17 11:48 ` Suthikulpanit, Suravee
2019-01-22 10:44 ` joro
2019-01-22 15:53 ` Suthikulpanit, Suravee
2019-01-23 7:56 ` joro
2019-01-24 3:25 ` Suthikulpanit, Suravee
2019-01-24 8:04 ` joro
2019-01-16 14:40 ` Suthikulpanit, Suravee
2019-01-16 17:09 ` joro
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