LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Nadav Amit <nadav.amit@gmail.com>
To: Joerg Roedel <joro@8bytes.org>
Cc: John Garry <john.garry@huawei.com>, Nadav Amit <namit@vmware.com>,
	Will Deacon <will@kernel.org>, Jiajun Cao <caojiajun@vmware.com>,
	Robin Murphy <robin.murphy@arm.com>,
	Lu Baolu <baolu.lu@linux.intel.com>,
	iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: [PATCH v6 6/7] iommu/amd: Sync once for scatter-gather operations
Date: Fri, 23 Jul 2021 02:32:08 -0700	[thread overview]
Message-ID: <20210723093209.714328-7-namit@vmware.com> (raw)
In-Reply-To: <20210723093209.714328-1-namit@vmware.com>

From: Nadav Amit <namit@vmware.com>

On virtual machines, software must flush the IOTLB after each page table
entry update.

The iommu_map_sg() code iterates through the given scatter-gather list
and invokes iommu_map() for each element in the scatter-gather list,
which calls into the vendor IOMMU driver through iommu_ops callback. As
the result, a single sg mapping may lead to multiple IOTLB flushes.

Fix this by adding amd_iotlb_sync_map() callback and flushing at this
point after all sg mappings we set.

This commit is followed and inspired by commit 933fcd01e97e2
("iommu/vt-d: Add iotlb_sync_map callback").

Cc: Joerg Roedel <joro@8bytes.org>
Cc: Will Deacon <will@kernel.org>
Cc: Jiajun Cao <caojiajun@vmware.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Cc: iommu@lists.linux-foundation.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Nadav Amit <namit@vmware.com>
---
 drivers/iommu/amd/iommu.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index f5d5f2124391..7846fcb1e92b 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -2022,6 +2022,16 @@ static int amd_iommu_attach_device(struct iommu_domain *dom,
 	return ret;
 }
 
+static void amd_iommu_iotlb_sync_map(struct iommu_domain *dom,
+				     unsigned long iova, size_t size)
+{
+	struct protection_domain *domain = to_pdomain(dom);
+	struct io_pgtable_ops *ops = &domain->iop.iop.ops;
+
+	if (ops->map)
+		domain_flush_np_cache(domain, iova, size);
+}
+
 static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova,
 			 phys_addr_t paddr, size_t page_size, int iommu_prot,
 			 gfp_t gfp)
@@ -2040,10 +2050,8 @@ static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova,
 	if (iommu_prot & IOMMU_WRITE)
 		prot |= IOMMU_PROT_IW;
 
-	if (ops->map) {
+	if (ops->map)
 		ret = ops->map(ops, iova, paddr, page_size, prot, gfp);
-		domain_flush_np_cache(domain, iova, page_size);
-	}
 
 	return ret;
 }
@@ -2223,6 +2231,7 @@ const struct iommu_ops amd_iommu_ops = {
 	.attach_dev = amd_iommu_attach_device,
 	.detach_dev = amd_iommu_detach_device,
 	.map = amd_iommu_map,
+	.iotlb_sync_map	= amd_iommu_iotlb_sync_map,
 	.unmap = amd_iommu_unmap,
 	.iova_to_phys = amd_iommu_iova_to_phys,
 	.probe_device = amd_iommu_probe_device,
-- 
2.25.1


  parent reply	other threads:[~2021-07-23 17:02 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-23  9:32 [PATCH v6 0/7] iommu/amd: Enable page-selective flushes Nadav Amit
2021-07-23  9:32 ` [PATCH v6 1/7] iommu/amd: Selective flush on unmap Nadav Amit
2021-07-23  9:32 ` [PATCH v6 2/7] iommu/amd: Do not use flush-queue when NpCache is on Nadav Amit
2021-07-23  9:32 ` [PATCH v6 3/7] iommu: Improve iommu_iotlb_gather helpers Nadav Amit
2021-07-23  9:32 ` [PATCH v6 4/7] iommu: Factor iommu_iotlb_gather_is_disjoint() out Nadav Amit
2021-07-23  9:32 ` [PATCH v6 5/7] iommu/amd: Tailored gather logic for AMD Nadav Amit
2021-07-23  9:32 ` Nadav Amit [this message]
2021-07-23  9:32 ` [PATCH v6 7/7] iommu/amd: Use only natural aligned flushes in a VM Nadav Amit
2021-07-26 12:31 ` [PATCH v6 0/7] iommu/amd: Enable page-selective flushes Joerg Roedel
2021-08-02  9:26 ` Joerg Roedel

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210723093209.714328-7-namit@vmware.com \
    --to=nadav.amit@gmail.com \
    --cc=baolu.lu@linux.intel.com \
    --cc=caojiajun@vmware.com \
    --cc=iommu@lists.linux-foundation.org \
    --cc=john.garry@huawei.com \
    --cc=joro@8bytes.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=namit@vmware.com \
    --cc=robin.murphy@arm.com \
    --cc=will@kernel.org \
    --subject='Re: [PATCH v6 6/7] iommu/amd: Sync once for scatter-gather operations' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).