[PATCH v6 6/6] iommu/tegra241-cmdqv: Limit CMDs for guest owned VINTF
From: Nicolin Chen
Date: Tue Apr 30 2024 - 00:45:40 EST
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 cmds to make sure every single command
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@xxxxxxxxxx>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 7 +--
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 5 ++-
.../iommu/arm/arm-smmu-v3/tegra241-cmdqv.c | 44 ++++++++++++++++++-
3 files changed, 50 insertions(+), 6 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 665a5e585f72..0802c3c96a2a 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -352,10 +352,11 @@ 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,
+ u64 *cmds, int n)
{
if (smmu->tegra241_cmdqv)
- return tegra241_cmdqv_get_cmdq(smmu);
+ return tegra241_cmdqv_get_cmdq(smmu, cmds, n);
return &smmu->cmdq;
}
@@ -766,7 +767,7 @@ static int arm_smmu_cmdq_issue_cmdlist(struct arm_smmu_device *smmu,
u32 prod;
unsigned long flags;
bool owner;
- struct arm_smmu_cmdq *cmdq = arm_smmu_get_cmdq(smmu);
+ struct arm_smmu_cmdq *cmdq = arm_smmu_get_cmdq(smmu, cmds, n);
struct arm_smmu_ll_queue llq, head;
int ret = 0;
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 87e4c227a937..e21e29f4770b 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -837,7 +837,8 @@ static inline void arm_smmu_sva_remove_dev_pasid(struct iommu_domain *domain,
struct tegra241_cmdqv *
tegra241_cmdqv_acpi_probe(struct arm_smmu_device *smmu, int id);
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,
+ u64 *cmds, int n);
#else /* CONFIG_TEGRA241_CMDQV */
static inline struct tegra241_cmdqv *
tegra241_cmdqv_acpi_probe(struct arm_smmu_device *smmu, int id)
@@ -851,7 +852,7 @@ 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, u64 *cmds, int n)
{
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 4b2af3aaa6b4..59ff2b740bec 100644
--- a/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
+++ b/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
@@ -266,6 +266,7 @@ struct tegra241_vcmdq {
* struct tegra241_vintf - Virtual Interface
* @idx: Global index in the CMDQV HW
* @status: cached status register
+ * @hyp_own: Owned by hypervisor (in-kernel)
* @cmdqv: CMDQV HW pointer
* @vcmdqs: List of VCMDQ pointers
* @base: MMIO base address
@@ -274,6 +275,7 @@ struct tegra241_vintf {
u16 idx;
atomic_t status;
+ bool hyp_own;
struct tegra241_cmdqv *cmdqv;
struct tegra241_vcmdq **vcmdqs;
@@ -372,7 +374,32 @@ static irqreturn_t tegra241_cmdqv_isr(int irq, void *devid)
return IRQ_HANDLED;
}
-struct arm_smmu_cmdq *tegra241_cmdqv_get_cmdq(struct arm_smmu_device *smmu)
+static bool tegra241_vintf_support_cmds(struct tegra241_vintf *vintf,
+ u64 *cmds, int n)
+{
+ int i;
+
+ /* VINTF owned by hypervisor can execute any command */
+ if (vintf->hyp_own)
+ return true;
+
+ /* Guest-owned VINTF must Check against the list of supported CMDs */
+ for (i = 0; i < n; i++) {
+ switch (FIELD_GET(CMDQ_0_OP, cmds[i * CMDQ_ENT_DWORDS])) {
+ case CMDQ_OP_TLBI_NH_ASID:
+ case CMDQ_OP_TLBI_NH_VA:
+ case CMDQ_OP_ATC_INV:
+ continue;
+ default:
+ return false;
+ }
+ }
+
+ return true;
+}
+
+struct arm_smmu_cmdq *tegra241_cmdqv_get_cmdq(struct arm_smmu_device *smmu,
+ u64 *cmds, int n)
{
struct tegra241_cmdqv *cmdqv = smmu->tegra241_cmdqv;
struct tegra241_vintf *vintf = cmdqv->vintfs[0];
@@ -390,6 +417,10 @@ struct arm_smmu_cmdq *tegra241_cmdqv_get_cmdq(struct arm_smmu_device *smmu)
if (FIELD_GET(VINTF_STATUS, atomic_read(&vintf->status)))
return &smmu->cmdq;
+ /* Unsupported CMDs go for smmu->cmdq pathway */
+ if (!tegra241_vintf_support_cmds(vintf, cmds, n))
+ return &smmu->cmdq;
+
/*
* Select a vcmdq to use. Here we use a temporal solution to
* balance out traffic on cmdq issuing: each cmdq has its own
@@ -590,6 +621,11 @@ int tegra241_cmdqv_device_reset(struct arm_smmu_device *smmu)
}
}
+ /*
+ * Note that HYP_OWN bit is wired to zero when running in guest kernel
+ * regardless of enabling it here, as !HYP_OWN cmdqs have a restricted
+ * set of supported commands, by following the HW design.
+ */
regval = FIELD_PREP(VINTF_HYP_OWN, 1);
vintf_writel(regval, CONFIG);
@@ -597,6 +633,12 @@ int tegra241_cmdqv_device_reset(struct arm_smmu_device *smmu)
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(CONFIG));
+
/* Build an arm_smmu_cmdq for each vcmdq allocated to vintf */
vintf->vcmdqs = devm_kcalloc(cmdqv->dev, cmdqv->num_vcmdqs_per_vintf,
sizeof(*vintf->vcmdqs), GFP_KERNEL);
--
2.43.0