linux-kernel - [PATCH v2 09/11] iommu/arm-smmu-v3: Clean up nested_ats_flush from master

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Message-ID: <c90ca01bcf0e61f2e9a7706d0019f6fb21895b78.1744692494.git.nicolinc@nvidia.com>
Date: Mon, 14 Apr 2025 21:57:44 -0700
From: Nicolin Chen <nicolinc@...dia.com>
To: <will@...nel.org>, <robin.murphy@....com>, <jgg@...dia.com>
CC: <joro@...tes.org>, <kevin.tian@...el.com>, <praan@...gle.com>,
	<nathan@...nel.org>, <yi.l.liu@...el.com>, <peterz@...radead.org>,
	<mshavit@...gle.com>, <jsnitsel@...hat.com>, <smostafa@...gle.com>,
	<jeff.johnson@....qualcomm.com>, <zhangzekun11@...wei.com>,
	<linux-arm-kernel@...ts.infradead.org>, <iommu@...ts.linux.dev>,
	<linux-kernel@...r.kernel.org>, <shameerali.kolothum.thodi@...wei.com>
Subject: [PATCH v2 09/11] iommu/arm-smmu-v3: Clean up nested_ats_flush from master_domain

Now the ats_devices list is maintained per vSMMU, since an S2 domain could
be shared among vSMMU instances.

Drop the nested_ats_flush from struct arm_smmu_master_domain, and clean up
the dead code in the related functions.

Signed-off-by: Nicolin Chen <nicolinc@...dia.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h |  1 -
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 24 ++++-----------------
 2 files changed, 4 insertions(+), 21 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index c9b9c7921bee..477d4d2f19a6 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -921,7 +921,6 @@ struct arm_smmu_master_domain {
 	struct list_head devices_elm;
 	struct arm_smmu_master *master;
 	ioasid_t ssid;
-	bool nested_ats_flush : 1;
 };
 
 static inline struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 483ef9e2c6b7..4b9cdfb177ca 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2221,16 +2221,7 @@ int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain,
 		if (!master->ats_enabled)
 			continue;
 
-		if (master_domain->nested_ats_flush) {
-			/*
-			 * If a S2 used as a nesting parent is changed we have
-			 * no option but to completely flush the ATC.
-			 */
-			arm_smmu_atc_inv_to_cmd(IOMMU_NO_PASID, 0, 0, &cmd);
-		} else {
-			arm_smmu_atc_inv_to_cmd(master_domain->ssid, iova, size,
-						&cmd);
-		}
+		arm_smmu_atc_inv_to_cmd(master_domain->ssid, iova, size, &cmd);
 
 		for (i = 0; i < master->num_streams; i++) {
 			cmd.atc.sid = master->streams[i].id;
@@ -2717,8 +2708,7 @@ static void arm_smmu_disable_pasid(struct arm_smmu_master *master)
 
 static struct arm_smmu_master_domain *
 arm_smmu_find_master_domain(struct arm_smmu_domain *smmu_domain,
-			    struct arm_smmu_master *master,
-			    ioasid_t ssid, bool nested_ats_flush)
+			    struct arm_smmu_master *master, ioasid_t ssid)
 {
 	struct arm_smmu_master_domain *master_domain;
 
@@ -2727,8 +2717,7 @@ arm_smmu_find_master_domain(struct arm_smmu_domain *smmu_domain,
 	list_for_each_entry(master_domain, &smmu_domain->devices,
 			    devices_elm) {
 		if (master_domain->master == master &&
-		    master_domain->ssid == ssid &&
-		    master_domain->nested_ats_flush == nested_ats_flush)
+		    master_domain->ssid == ssid)
 			return master_domain;
 	}
 	return NULL;
@@ -2759,7 +2748,6 @@ static void arm_smmu_remove_master_domain(struct arm_smmu_master *master,
 {
 	struct arm_smmu_domain *smmu_domain = to_smmu_domain_devices(domain);
 	struct arm_smmu_master_domain *master_domain;
-	bool nested_ats_flush = false;
 	unsigned long flags;
 
 	if (!smmu_domain)
@@ -2772,8 +2760,7 @@ static void arm_smmu_remove_master_domain(struct arm_smmu_master *master,
 	}
 
 	spin_lock_irqsave(&smmu_domain->devices_lock, flags);
-	master_domain = arm_smmu_find_master_domain(smmu_domain, master, ssid,
-						    nested_ats_flush);
+	master_domain = arm_smmu_find_master_domain(smmu_domain, master, ssid);
 	if (master_domain) {
 		list_del(&master_domain->devices_elm);
 		kfree(master_domain);
@@ -2853,9 +2840,6 @@ int arm_smmu_attach_prepare(struct arm_smmu_attach_state *state,
 			return -ENOMEM;
 		master_domain->master = master;
 		master_domain->ssid = state->ssid;
-		if (new_domain->type == IOMMU_DOMAIN_NESTED)
-			master_domain->nested_ats_flush =
-				to_smmu_nested_domain(new_domain)->enable_ats;
 
 		/*
 		 * During prepare we want the current smmu_domain and new
-- 
2.43.0