[PATCH 08/12] iommu/vt-d: Support Enhanced Command Interface
From: Lu Baolu
Date: Tue Jan 31 2023 - 02:46:31 EST
From: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230128200428.1459118-4-kan.liang@xxxxxxxxxxxxxxx
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
---
drivers/iommu/intel/iommu.h | 33 ++++++++++++++++++++++
drivers/iommu/intel/dmar.c | 10 +++++++
drivers/iommu/intel/iommu.c | 56 +++++++++++++++++++++++++++++++++++++
3 files changed, 99 insertions(+)
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
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;
+}
--
2.34.1