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Message-ID: <20240906121308.5013-5-suravee.suthikulpanit@amd.com>
Date: Fri, 6 Sep 2024 12:13:07 +0000
From: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
To: <linux-kernel@...r.kernel.org>, <iommu@...ts.linux.dev>
CC: <joro@...tes.org>, <robin.murphy@....com>, <vasant.hegde@....com>,
<ubizjak@...il.com>, <jgg@...dia.com>, <jon.grimm@....com>,
<santosh.shukla@....com>, <pandoh@...gle.com>, <kumaranand@...gle.com>,
Suravee Suthikulpanit <suravee.suthikulpanit@....com>
Subject: [PATCH v3 4/5] iommu/amd: Modify clear_dte_entry() to avoid in-place update
Lock DTE and copy value to a temporary storage before update using
cmpxchg128.
Also, refactor the function to simplify logic for applying erratum 63.
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
---
drivers/iommu/amd/amd_iommu_types.h | 2 ++
drivers/iommu/amd/iommu.c | 27 ++++++++++++++++++++-------
2 files changed, 22 insertions(+), 7 deletions(-)
diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h
index 1836da2d9e60..81a994471a30 100644
--- a/drivers/iommu/amd/amd_iommu_types.h
+++ b/drivers/iommu/amd/amd_iommu_types.h
@@ -425,6 +425,8 @@
#define DTE_GPT_LEVEL_SHIFT 54
+#define DTE_SYSMGT_MASK GENMASK_ULL(41, 40)
+
#define GCR3_VALID 0x01ULL
#define IOMMU_PAGE_MASK (((1ULL << 52) - 1) & ~0xfffULL)
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index f18ae6c077f4..15eb816d4313 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -2025,19 +2025,32 @@ static void set_dte_entry(struct amd_iommu *iommu,
}
}
-static void clear_dte_entry(struct amd_iommu *iommu, u16 devid)
+static void clear_dte_entry(struct amd_iommu *iommu, struct iommu_dev_data *dev_data)
{
- struct dev_table_entry *dev_table = get_dev_table(iommu);
+ struct dev_table_entry new;
+ struct dev_table_entry *dte = &get_dev_table(iommu)[dev_data->devid];
+
+ /*
+ * Need to preserve DTE[96:106] because certain fields are
+ * programmed using value in IVRS table from early init phase.
+ */
+ spin_lock(&dev_data->dte_lock);
+ get_dte256(iommu, dev_data, &new);
/* remove entry from the device table seen by the hardware */
- dev_table[devid].data[0] = DTE_FLAG_V;
+ new.data[0] = DTE_FLAG_V;
if (!amd_iommu_snp_en)
- dev_table[devid].data[0] |= DTE_FLAG_TV;
+ new.data[0] |= DTE_FLAG_TV;
- dev_table[devid].data[1] &= DTE_FLAG_MASK;
+ new.data[1] &= DTE_FLAG_MASK;
- amd_iommu_apply_erratum_63(iommu, devid);
+ /* Apply erratum 63 */
+ if (FIELD_GET(DTE_SYSMGT_MASK, new.data[1]) == 0x01)
+ new.data[0] |= BIT_ULL(DEV_ENTRY_IW);
+
+ WARN_ON(!try_cmpxchg128(&dte->data128[0], &dte->data128[0], new.data128[0]));
+ spin_unlock(&dev_data->dte_lock);
}
/* Update and flush DTE for the given device */
@@ -2048,7 +2061,7 @@ void amd_iommu_dev_update_dte(struct iommu_dev_data *dev_data, bool set)
if (set)
set_dte_entry(iommu, dev_data);
else
- clear_dte_entry(iommu, dev_data->devid);
+ clear_dte_entry(iommu, dev_data);
clone_aliases(iommu, dev_data->dev);
device_flush_dte(dev_data);
--
2.34.1
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