[PATCH v8 18/25] iommu/arm-smmu-v3-kvm: Shadow STEs

[Mostafa Saleh]

Add STE emulation, when the host sends the CFGI_STE command.

Copy the STE as is to the shadow owned by the hypervisor,
which is the one seen by HW.
In the next patch, stage-2 page table will be attached.

Signed-off-by: Mostafa Saleh <smostafa at google.com>
---
 .../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c  | 124 +++++++++++++++++-
 1 file changed, 118 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index 54049b8b1363..cb9aa7e4a394 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -24,6 +24,9 @@ struct hyp_arm_smmu_v3_device *kvm_hyp_arm_smmu_v3_smmus;
 #define strtab_split(smmu)	(FIELD_GET(STRTAB_BASE_CFG_SPLIT, (smmu)->host_ste_cfg))
 #define strtab_l1_size(smmu)	((1UL << (strtab_log2size(smmu) - strtab_split(smmu))) * \
 				 (sizeof(struct arm_smmu_strtab_l1)))
+#define strtab_hyp_base(smmu)	((smmu)->features & ARM_SMMU_FEAT_2_LVL_STRTAB ? \
+				 (u64 *)(smmu)->strtab_cfg.l2.l1tab :\
+				 (u64 *)(smmu)->strtab_cfg.linear.table)
 
 #define for_each_smmu(smmu) \
 	for ((smmu) = kvm_hyp_arm_smmu_v3_smmus; \
@@ -287,6 +290,91 @@ static int smmu_init_cmdq(struct hyp_arm_smmu_v3_device *smmu)
 	return 0;
 }
 
+static int smmu_get_host_l2_ste(struct hyp_arm_smmu_v3_device *smmu, u32 sid,
+				struct arm_smmu_ste *host_ste_out)
+{
+	u64 *host_ste_base = hyp_phys_to_virt(strtab_host_base(smmu));
+	struct arm_smmu_strtab_l1 host_l1_desc;
+	struct arm_smmu_strtab_l2 *l2ptr;
+	phys_addr_t host_l2_tab;
+	int ret, i;
+
+	host_l1_desc.l2ptr = READ_ONCE(host_ste_base[arm_smmu_strtab_l1_idx(sid)]);
+	if (!(le64_to_cpu(host_l1_desc.l2ptr) & STRTAB_L1_DESC_SPAN))
+		return -EINVAL;
+
+	host_l2_tab = le64_to_cpu(host_l1_desc.l2ptr) & STRTAB_L1_DESC_L2PTR_MASK;
+	/* Share and pin the table before accessing it. */
+	ret = smmu_share_pages(host_l2_tab, sizeof(struct arm_smmu_strtab_l2));
+	if (ret)
+		return ret;
+
+	l2ptr = hyp_phys_to_virt(host_l2_tab);
+
+	for (i = 0; i < STRTAB_STE_DWORDS; ++i)
+		host_ste_out->data[i] =
+			READ_ONCE(l2ptr->stes[arm_smmu_strtab_l2_idx(sid)].data[i]);
+
+	WARN_ON(smmu_unshare_pages(host_l2_tab, sizeof(struct arm_smmu_strtab_l2)));
+	return 0;
+}
+
+static int smmu_reshadow_ste(struct hyp_arm_smmu_v3_device *smmu, u32 sid, bool leaf)
+{
+	struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;
+	struct arm_smmu_ste *hyp_ste_ptr, *host_ste_ptr, host_ste_copy;
+	u64 *hyp_ste_base = strtab_hyp_base(smmu);
+	int ret, i;
+
+	/* Leaf = 0 is not supported, as the kernel driver. */
+	if (!leaf || !is_smmu_enabled(smmu) ||
+	    (sid >= (1UL << strtab_log2size(smmu))))
+		return -EINVAL;
+
+	if (!(smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB)) {
+		struct arm_smmu_ste *hyp_table = (struct arm_smmu_ste *)hyp_ste_base;
+		u64 *host_ste_base = hyp_phys_to_virt(strtab_host_base(smmu));
+		struct arm_smmu_ste *host_table = (struct arm_smmu_ste *)host_ste_base;
+
+		if (sid >= cfg->linear.num_ents)
+			return -E2BIG;
+
+		hyp_ste_ptr = &hyp_table[sid];
+		host_ste_ptr = &host_table[sid];
+	} else {
+		struct arm_smmu_strtab_l1 *l1tab = (struct arm_smmu_strtab_l1 *)hyp_ste_base;
+		u32 l1_idx = arm_smmu_strtab_l1_idx(sid);
+		struct arm_smmu_strtab_l2 *l2ptr;
+
+		if (l1_idx >= cfg->l2.num_l1_ents)
+			return -E2BIG;
+
+		host_ste_ptr = &host_ste_copy;
+		ret = smmu_get_host_l2_ste(smmu, sid, host_ste_ptr);
+		if (ret)
+			return ret;
+
+		/* No hypervisor entry, first time the L2 is populated. */
+		if (!l1tab[l1_idx].l2ptr) {
+			struct arm_smmu_strtab_l2 *l2table;
+
+			l2table = pkvm_iommu_alloc_pages(get_order(sizeof(*l2table)));
+			if (!l2table)
+				return -ENOMEM;
+			/* Ensure L2 is observed before writing the ptr. */
+			dma_wmb();
+			arm_smmu_write_strtab_l1_desc(&l1tab[l1_idx], hyp_virt_to_phys(l2table));
+		}
+		l2ptr = hyp_phys_to_virt(le64_to_cpu(l1tab[l1_idx].l2ptr) &
+				STRTAB_L1_DESC_L2PTR_MASK);
+		hyp_ste_ptr = &l2ptr->stes[arm_smmu_strtab_l2_idx(sid)];
+	}
+
+	for (i = 0; i < STRTAB_STE_DWORDS; ++i)
+		WRITE_ONCE(hyp_ste_ptr->data[i], host_ste_ptr->data[i]);
+	return 0;
+}
+
 static int smmu_init_strtab(struct hyp_arm_smmu_v3_device *smmu)
 {
 	struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;
@@ -406,8 +494,24 @@ static bool smmu_filter_command(struct hyp_arm_smmu_v3_device *smmu, u64 *comman
 
 	switch (type) {
 	case CMDQ_OP_CFGI_STE:
-		/* TBD: SHADOW_STE*/
+	{
+		u32 leaf = FIELD_GET(CMDQ_CFGI_1_LEAF, command[1]);
+		u32 sid = FIELD_GET(CMDQ_CFGI_0_SID, command[0]);
+		int ret;
+
+		/*
+		 * If STE update is required, flush the CMDQ and drop the lock as that
+		 * might require to update the host page table and acquire its lock.
+		 */
+		writel(smmu->cmdq.llq.prod, smmu->cmdq.prod_reg);
+		hyp_spin_unlock(&smmu->hw_lock);
+		ret = smmu_reshadow_ste(smmu, sid, leaf);
+		hyp_spin_lock(&smmu->hw_lock);
+		if (ret)
+			return true;
+
 		break;
+	}
 	case CMDQ_OP_CFGI_ALL:
 	{
 		/*
@@ -624,25 +728,33 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
 			val = smmu->cmdq_host.llq.cons | (CMDQ_CONS_ERR & cons);
 			goto out_update_regs;
 		}
-	/* Passthrough the register access for bisectability, handled later */
 	case ARM_SMMU_STRTAB_BASE:
+		if (len != sizeof(u64))
+			break;
 		if (is_write) {
 			/* Must only be written when SMMU_CR0.SMMUEN == 0.*/
 			if (is_smmu_enabled(smmu))
 				break;
 			smmu->host_ste_base = val;
+			goto out_ret;
+		} else {
+			val = smmu->host_ste_base;
+			goto out_update_regs;
 		}
-		mask = read_write;
-		break;
 	case ARM_SMMU_STRTAB_BASE_CFG:
+		if (len != sizeof(u32))
+			break;
 		if (is_write) {
 			/* Must only be written when SMMU_CR0.SMMUEN == 0.*/
 			if (is_smmu_enabled(smmu))
 				break;
 			smmu->host_ste_cfg = val;
+			goto out_ret;
+		} else {
+			val = smmu->host_ste_cfg;
+			goto out_update_regs;
 		}
-		mask = read_write;
-		break;
+	/* Passthrough the register access for bisectability, handled later */
 	case ARM_SMMU_GBPA:
 		mask = read_write;
 		break;
-- 
2.55.0.1082.g2b9226bbc0-goog