iommu/vt-d: Support Enhanced Command Interface

The Enhanced Command Register is to submit command and operand of
enhanced commands to DMA Remapping hardware. It can supports up to 256
enhanced commands.

There is a HW register to indicate the availability of all 256 enhanced
commands. Each bit stands for each command. But there isn't an existing
interface to read/write all 256 bits. Introduce the u64 ecmdcap[4] to
store the existence of each enhanced command. Read 4 times to get all of
them in map_iommu().

Add a helper to facilitate an enhanced command launch. Make sure hardware
complete the command. Also add a helper to facilitate the check of PMU
essentials. These helpers will be used later.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Link: https://lore.kernel.org/r/20230128200428.1459118-4-kan.liang@linux.intel.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

3 files changed, 99 insertions, 0 deletions

diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
index 7a03cadb13ff..0e429bab436f 100644
--- a/drivers/iommu/intel/dmar.c
+++ b/drivers/iommu/intel/dmar.c
@@ -1017,6 +1017,16 @@ static int map_iommu(struct intel_iommu *iommu, struct dmar_drhd_unit *drhd)
 			goto release;
 		}
 	}
+
+	if (cap_ecmds(iommu->cap)) {
+		int i;
+
+		for (i = 0; i < DMA_MAX_NUM_ECMDCAP; i++) {
+			iommu->ecmdcap[i] = dmar_readq(iommu->reg + DMAR_ECCAP_REG +
+						       i * DMA_ECMD_REG_STEP);
+		}
+	}
+
 	err = 0;
 	goto out;
 
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 317af67b6098..e314c30d371a 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -5022,3 +5022,59 @@ void quirk_extra_dev_tlb_flush(struct device_domain_info *info,
 					 pasid, qdep, address, mask);
 	}
 }
+
+#define ecmd_get_status_code(res)	(((res) & 0xff) >> 1)
+
+/*
+ * Function to submit a command to the enhanced command interface. The
+ * valid enhanced command descriptions are defined in Table 47 of the
+ * VT-d spec. The VT-d hardware implementation may support some but not
+ * all commands, which can be determined by checking the Enhanced
+ * Command Capability Register.
+ *
+ * Return values:
+ *  - 0: Command successful without any error;
+ *  - Negative: software error value;
+ *  - Nonzero positive: failure status code defined in Table 48.
+ */
+int ecmd_submit_sync(struct intel_iommu *iommu, u8 ecmd, u64 oa, u64 ob)
+{
+	unsigned long flags;
+	u64 res;
+	int ret;
+
+	if (!cap_ecmds(iommu->cap))
+		return -ENODEV;
+
+	raw_spin_lock_irqsave(&iommu->register_lock, flags);
+
+	res = dmar_readq(iommu->reg + DMAR_ECRSP_REG);
+	if (res & DMA_ECMD_ECRSP_IP) {
+		ret = -EBUSY;
+		goto err;
+	}
+
+	/*
+	 * Unconditionally write the operand B, because
+	 * - There is no side effect if an ecmd doesn't require an
+	 *   operand B, but we set the register to some value.
+	 * - It's not invoked in any critical path. The extra MMIO
+	 *   write doesn't bring any performance concerns.
+	 */
+	dmar_writeq(iommu->reg + DMAR_ECEO_REG, ob);
+	dmar_writeq(iommu->reg + DMAR_ECMD_REG, ecmd | (oa << DMA_ECMD_OA_SHIFT));
+
+	IOMMU_WAIT_OP(iommu, DMAR_ECRSP_REG, dmar_readq,
+		      !(res & DMA_ECMD_ECRSP_IP), res);
+
+	if (res & DMA_ECMD_ECRSP_IP) {
+		ret = -ETIMEDOUT;
+		goto err;
+	}
+
+	ret = ecmd_get_status_code(res);
+err:
+	raw_spin_unlock_irqrestore(&iommu->register_lock, flags);
+
+	return ret;
+}
diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index f03d4b6bf49a..f918e83bf91c 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -130,6 +130,10 @@
 #define DMAR_PERFOVFOFF_REG	0x318
 #define DMAR_PERFCNTROFF_REG	0x31c
 #define DMAR_PERFEVNTCAP_REG	0x380
+#define DMAR_ECMD_REG		0x400
+#define DMAR_ECEO_REG		0x408
+#define DMAR_ECRSP_REG		0x410
+#define DMAR_ECCAP_REG		0x430
 #define DMAR_VCCAP_REG		0xe30 /* Virtual command capability register */
 #define DMAR_VCMD_REG		0xe00 /* Virtual command register */
 #define DMAR_VCRSP_REG		0xe10 /* Virtual command response register */
@@ -304,6 +308,26 @@
 #define DMA_CCMD_SID(s) (((u64)((s) & 0xffff)) << 16)
 #define DMA_CCMD_DID(d) ((u64)((d) & 0xffff))
 
+/* ECMD_REG */
+#define DMA_MAX_NUM_ECMD		256
+#define DMA_MAX_NUM_ECMDCAP		(DMA_MAX_NUM_ECMD / 64)
+#define DMA_ECMD_REG_STEP		8
+#define DMA_ECMD_ENABLE			0xf0
+#define DMA_ECMD_DISABLE		0xf1
+#define DMA_ECMD_FREEZE			0xf4
+#define DMA_ECMD_UNFREEZE		0xf5
+#define DMA_ECMD_OA_SHIFT		16
+#define DMA_ECMD_ECRSP_IP		0x1
+#define DMA_ECMD_ECCAP3			3
+#define DMA_ECMD_ECCAP3_ECNTS		BIT_ULL(48)
+#define DMA_ECMD_ECCAP3_DCNTS		BIT_ULL(49)
+#define DMA_ECMD_ECCAP3_FCNTS		BIT_ULL(52)
+#define DMA_ECMD_ECCAP3_UFCNTS		BIT_ULL(53)
+#define DMA_ECMD_ECCAP3_ESSENTIAL	(DMA_ECMD_ECCAP3_ECNTS |	\
+					 DMA_ECMD_ECCAP3_DCNTS |	\
+					 DMA_ECMD_ECCAP3_FCNTS |	\
+					 DMA_ECMD_ECCAP3_UFCNTS)
+
 /* FECTL_REG */
 #define DMA_FECTL_IM (((u32)1) << 31)
 
@@ -605,6 +629,7 @@ struct intel_iommu {
 	u64		cap;
 	u64		ecap;
 	u64		vccap;
+	u64		ecmdcap[DMA_MAX_NUM_ECMDCAP];
 	u32		gcmd; /* Holds TE, EAFL. Don't need SRTP, SFL, WBF */
 	raw_spinlock_t	register_lock; /* protect register handling */
 	int		seq_id;	/* sequence id of the iommu */
@@ -840,6 +865,14 @@ extern const struct iommu_ops intel_iommu_ops;
 extern int intel_iommu_sm;
 extern int iommu_calculate_agaw(struct intel_iommu *iommu);
 extern int iommu_calculate_max_sagaw(struct intel_iommu *iommu);
+int ecmd_submit_sync(struct intel_iommu *iommu, u8 ecmd, u64 oa, u64 ob);
+
+static inline bool ecmd_has_pmu_essential(struct intel_iommu *iommu)
+{
+	return (iommu->ecmdcap[DMA_ECMD_ECCAP3] & DMA_ECMD_ECCAP3_ESSENTIAL) ==
+		DMA_ECMD_ECCAP3_ESSENTIAL;
+}
+
 extern int dmar_disabled;
 extern int intel_iommu_enabled;
 #else