[PATCH v7 6/6] iommu/tegra241-cmdqv: Limit CMDs for guest owned VINTF

From: Nicolin Chen <nicolinc@nvidia.com>
To: <will@kernel.org>, <robin.murphy@arm.com>, <jgg@nvidia.com>
Cc: <joro@8bytes.org>, <thierry.reding@gmail.com>,
	<vdumpa@nvidia.com>, <jonathanh@nvidia.com>,
	<linux-kernel@vger.kernel.org>, <iommu@lists.linux.dev>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-tegra@vger.kernel.org>
Subject: [PATCH v7 6/6] iommu/tegra241-cmdqv: Limit CMDs for guest owned VINTF
Date: Tue, 7 May 2024 22:56:54 -0700	[thread overview]
Message-ID: <062cf0a1e2b8ec6f068262cc68498b8d72b04bcc.1715147377.git.nicolinc@nvidia.com> (raw)
In-Reply-To: <cover.1715147377.git.nicolinc@nvidia.com>

When VCMDQs are assigned to a VINTF owned by a guest (HYP_OWN bit unset),
only TLB and ATC invalidation commands are supported by the VCMDQ HW. So,
add a new helper to scan the input cmd to make sure it is supported when
selecting a queue.

Note that the guest VM shouldn't have HYP_OWN bit being set regardless of
guest kernel driver writing it or not, i.e. the hypervisor running in the
host OS should wire this bit to zero when trapping a write access to this
VINTF_CONFIG register from a guest kernel.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   | 20 ++++++-----
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  5 +--
 .../iommu/arm/arm-smmu-v3/tegra241-cmdqv.c    | 36 ++++++++++++++++++-
 3 files changed, 49 insertions(+), 12 deletions(-)

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 d1098991d64e..baf20e9976d3 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -332,10 +332,11 @@ static int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent)
 	return 0;
 }
 
-static struct arm_smmu_cmdq *arm_smmu_get_cmdq(struct arm_smmu_device *smmu)
+static struct arm_smmu_cmdq *
+arm_smmu_get_cmdq(struct arm_smmu_device *smmu, u8 opcode)
 {
 	if (arm_smmu_has_tegra241_cmdqv(smmu))
-		return tegra241_cmdqv_get_cmdq(smmu);
+		return tegra241_cmdqv_get_cmdq(smmu, opcode);
 
 	return &smmu->cmdq;
 }
@@ -871,7 +872,7 @@ static int __arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu,
 	}
 
 	return arm_smmu_cmdq_issue_cmdlist(
-		smmu, arm_smmu_get_cmdq(smmu), cmd, 1, sync);
+		smmu, arm_smmu_get_cmdq(smmu, ent->opcode), cmd, 1, sync);
 }
 
 static int arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu,
@@ -887,10 +888,11 @@ static int arm_smmu_cmdq_issue_cmd_with_sync(struct arm_smmu_device *smmu,
 }
 
 static void arm_smmu_cmdq_batch_init(struct arm_smmu_device *smmu,
-				     struct arm_smmu_cmdq_batch *cmds)
+				     struct arm_smmu_cmdq_batch *cmds,
+				     u8 opcode)
 {
 	cmds->num = 0;
-	cmds->cmdq = arm_smmu_get_cmdq(smmu);
+	cmds->cmdq = arm_smmu_get_cmdq(smmu, opcode);
 }
 
 static void arm_smmu_cmdq_batch_add(struct arm_smmu_device *smmu,
@@ -1167,7 +1169,7 @@ static void arm_smmu_sync_cd(struct arm_smmu_master *master,
 		},
 	};
 
-	arm_smmu_cmdq_batch_init(smmu, &cmds);
+	arm_smmu_cmdq_batch_init(smmu, &cmds, cmd.opcode);
 	for (i = 0; i < master->num_streams; i++) {
 		cmd.cfgi.sid = master->streams[i].id;
 		arm_smmu_cmdq_batch_add(smmu, &cmds, &cmd);
@@ -2006,7 +2008,7 @@ static int arm_smmu_atc_inv_master(struct arm_smmu_master *master)
 
 	arm_smmu_atc_inv_to_cmd(IOMMU_NO_PASID, 0, 0, &cmd);
 
-	arm_smmu_cmdq_batch_init(master->smmu, &cmds);
+	arm_smmu_cmdq_batch_init(master->smmu, &cmds, cmd.opcode);
 	for (i = 0; i < master->num_streams; i++) {
 		cmd.atc.sid = master->streams[i].id;
 		arm_smmu_cmdq_batch_add(master->smmu, &cmds, &cmd);
@@ -2046,7 +2048,7 @@ int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain, int ssid,
 
 	arm_smmu_atc_inv_to_cmd(ssid, iova, size, &cmd);
 
-	arm_smmu_cmdq_batch_init(smmu_domain->smmu, &cmds);
+	arm_smmu_cmdq_batch_init(smmu_domain->smmu, &cmds, cmd.opcode);
 
 	spin_lock_irqsave(&smmu_domain->devices_lock, flags);
 	list_for_each_entry(master, &smmu_domain->devices, domain_head) {
@@ -2123,7 +2125,7 @@ static void __arm_smmu_tlb_inv_range(struct arm_smmu_cmdq_ent *cmd,
 			num_pages++;
 	}
 
-	arm_smmu_cmdq_batch_init(smmu_domain->smmu, &cmds);
+	arm_smmu_cmdq_batch_init(smmu_domain->smmu, &cmds, cmd->opcode);
 
 	while (iova < end) {
 		if (smmu->features & ARM_SMMU_FEAT_RANGE_INV) {
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 604e26a292e7..2c1fe7e129cd 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -879,7 +879,8 @@ struct tegra241_cmdqv *tegra241_cmdqv_acpi_probe(struct arm_smmu_device *smmu,
 						 struct acpi_iort_node *node);
 void tegra241_cmdqv_device_remove(struct arm_smmu_device *smmu);
 int tegra241_cmdqv_device_reset(struct arm_smmu_device *smmu);
-struct arm_smmu_cmdq *tegra241_cmdqv_get_cmdq(struct arm_smmu_device *smmu);
+struct arm_smmu_cmdq *tegra241_cmdqv_get_cmdq(struct arm_smmu_device *smmu,
+					      u8 opcode);
 #else /* CONFIG_TEGRA241_CMDQV */
 static inline bool arm_smmu_has_tegra241_cmdqv(struct arm_smmu_device *smmu)
 {
@@ -903,7 +904,7 @@ static inline int tegra241_cmdqv_device_reset(struct arm_smmu_device *smmu)
 }
 
 static inline struct arm_smmu_cmdq *
-tegra241_cmdqv_get_cmdq(struct arm_smmu_device *smmu)
+tegra241_cmdqv_get_cmdq(struct arm_smmu_device *smmu, u8 opcode)
 {
 	return NULL;
 }
diff --git a/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c b/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
index ec4767e3859e..e7a281131e5d 100644
--- a/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
+++ b/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
@@ -181,6 +181,7 @@ struct tegra241_vcmdq {
  * struct tegra241_vintf - Virtual Interface
  * @idx: Global index in the CMDQV
  * @enabled: Enable status
+ * @hyp_own: Owned by hypervisor (in-kernel)
  * @cmdqv: Parent CMDQV pointer
  * @lvcmdqs: List of logical VCMDQ pointers
  * @base: MMIO base address
@@ -189,6 +190,7 @@ struct tegra241_vintf {
 	u16 idx;
 
 	bool enabled;
+	bool hyp_own;
 
 	struct tegra241_cmdqv *cmdqv;
 	struct tegra241_vcmdq **lvcmdqs;
@@ -326,7 +328,25 @@ static irqreturn_t tegra241_cmdqv_isr(int irq, void *devid)
 
 /* Command Queue Selecting Function */
 
-struct arm_smmu_cmdq *tegra241_cmdqv_get_cmdq(struct arm_smmu_device *smmu)
+static bool tegra241_vintf_support_cmd(struct tegra241_vintf *vintf, u8 opcode)
+{
+       /* Hypervisor-owned VINTF can execute any command in its VCMDQs */
+	if (READ_ONCE(vintf->hyp_own))
+		return true;
+
+	/* Guest-owned VINTF must Check against the list of supported CMDs */
+	switch (opcode) {
+	case CMDQ_OP_TLBI_NH_ASID:
+	case CMDQ_OP_TLBI_NH_VA:
+	case CMDQ_OP_ATC_INV:
+		return true;
+	default:
+		return false;
+	}
+}
+
+struct arm_smmu_cmdq *tegra241_cmdqv_get_cmdq(struct arm_smmu_device *smmu,
+					      u8 opcode)
 {
 	struct tegra241_cmdqv *cmdqv = smmu->tegra241_cmdqv;
 	struct tegra241_vintf *vintf = cmdqv->vintfs[0];
@@ -340,6 +360,10 @@ struct arm_smmu_cmdq *tegra241_cmdqv_get_cmdq(struct arm_smmu_device *smmu)
 	if (!READ_ONCE(vintf->enabled))
 		return &smmu->cmdq;
 
+	/* Unsupported CMD go for smmu->cmdq pathway */
+	if (!tegra241_vintf_support_cmd(vintf, opcode))
+		return &smmu->cmdq;
+
 	/*
 	 * Select a LVCMDQ to use. Here we use a temporal solution to
 	 * balance out traffic on cmdq issuing: each cmdq has its own
@@ -432,12 +456,22 @@ static int tegra241_vintf_hw_init(struct tegra241_vintf *vintf, bool hyp_own)
 	tegra241_vintf_hw_deinit(vintf);
 
 	/* Configure and enable VINTF */
+	/*
+	 * Note that HYP_OWN bit is wired to zero when running in guest kernel,
+	 * whether enabling it here or not, as !HYP_OWN cmdq HWs only support a
+	 * restricted set of supported commands.
+	 */
 	regval = FIELD_PREP(VINTF_HYP_OWN, hyp_own);
 	vintf_writel(vintf, regval, CONFIG);
 
 	ret = vintf_write_config(vintf, regval | VINTF_EN);
 	if (ret)
 		return ret;
+	/*
+	 * As being mentioned above, HYP_OWN bit is wired to zero for a guest
+	 * kernel, so read it back from HW to ensure that reflects in hyp_own
+	 */
+	vintf->hyp_own = !!(VINTF_HYP_OWN & vintf_readl(vintf, CONFIG));
 
 	for (lidx = 0; lidx < vintf->cmdqv->num_lvcmdqs_per_vintf; lidx++) {
 		if (vintf->lvcmdqs && vintf->lvcmdqs[lidx]) {
-- 
2.43.0


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