Revert "ANDROID: KVM: arm64: Remove unused IOMMU hooks, kvm_iommu_ops"

This reverts commit 6122181d63.

Bug: 233587962
Signed-off-by: Will Deacon <willdeacon@google.com>
Change-Id: I2978dfcba76e8b4e0a3cf7b6bc450b05123ede3e

arch/arm64/include/asm/kvm_host.h

@@ -375,6 +375,10 @@ extern s64 kvm_nvhe_sym(hyp_physvirt_offset);
 extern u64 kvm_nvhe_sym(hyp_cpu_logical_map)[NR_CPUS];
 #define hyp_cpu_logical_map CHOOSE_NVHE_SYM(hyp_cpu_logical_map)
 
+enum kvm_iommu_driver {
+	KVM_IOMMU_DRIVER_NONE,
+};
+
 enum pkvm_iommu_driver_id {
 	PKVM_IOMMU_DRIVER_S2MPU,
 	PKVM_IOMMU_NR_DRIVERS,

arch/arm64/include/asm/kvm_hyp.h

@@ -110,7 +110,8 @@ void __noreturn __hyp_do_panic(struct kvm_cpu_context *host_ctxt, u64 spsr,
 void __pkvm_init_switch_pgd(phys_addr_t phys, unsigned long size,
 			    phys_addr_t pgd, void *sp, void *cont_fn);
 int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
-		unsigned long *per_cpu_base, u32 hyp_va_bits);
+		unsigned long *per_cpu_base, u32 hyp_va_bits,
+		enum kvm_iommu_driver iommu_driver);
 void __noreturn __host_enter(struct kvm_cpu_context *host_ctxt);
 #endif
 

arch/arm64/kvm/arm.c

@@ -1902,6 +1902,11 @@ static bool init_psci_relay(void)
 	return true;
 }
 
+static int init_stage2_iommu(void)
+{
+	return KVM_IOMMU_DRIVER_NONE;
+}
+
 static int init_subsystems(void)
 {
 	int err = 0;
@@ -1961,7 +1966,7 @@ static void teardown_hyp_mode(void)
 	}
 }
 
-static int do_pkvm_init(u32 hyp_va_bits)
+static int do_pkvm_init(u32 hyp_va_bits, enum kvm_iommu_driver iommu_driver)
 {
 	void *per_cpu_base = kvm_ksym_ref(kvm_arm_hyp_percpu_base);
 	int ret;
@@ -1970,7 +1975,7 @@ static int do_pkvm_init(u32 hyp_va_bits)
 	cpu_hyp_init_context();
 	ret = kvm_call_hyp_nvhe(__pkvm_init, hyp_mem_base, hyp_mem_size,
 				num_possible_cpus(), kern_hyp_va(per_cpu_base),
-				hyp_va_bits);
+				hyp_va_bits, iommu_driver);
 	cpu_hyp_init_features();
 
 	/*
@@ -2002,7 +2007,11 @@ static int kvm_hyp_init_protection(u32 hyp_va_bits)
 	if (ret)
 		return ret;
 
-	ret = do_pkvm_init(hyp_va_bits);
+	ret = init_stage2_iommu();
+	if (ret < 0)
+		return ret;
+
+	ret = do_pkvm_init(hyp_va_bits, (enum kvm_iommu_driver)ret);
 	if (ret)
 		return ret;
 

arch/arm64/kvm/hyp/include/nvhe/iommu.h

@@ -82,4 +82,18 @@ void pkvm_iommu_host_stage2_idmap(phys_addr_t start, phys_addr_t end,
 
 extern const struct pkvm_iommu_ops pkvm_s2mpu_ops;
 
+struct kvm_iommu_ops {
+	int (*init)(void);
+	bool (*host_smc_handler)(struct kvm_cpu_context *host_ctxt);
+	bool (*host_mmio_dabt_handler)(struct kvm_cpu_context *host_ctxt,
+				       phys_addr_t fault_pa, unsigned int len,
+				       bool is_write, int rd);
+	void (*host_stage2_set_owner)(phys_addr_t addr, size_t size, pkvm_id owner_id);
+	int (*host_stage2_adjust_mmio_range)(phys_addr_t addr, phys_addr_t *start,
+					     phys_addr_t *end);
+};
+
+extern struct kvm_iommu_ops kvm_iommu_ops;
+extern const struct kvm_iommu_ops kvm_s2mpu_ops;
+
 #endif	/* __ARM64_KVM_NVHE_IOMMU_H__ */

arch/arm64/kvm/hyp/nvhe/hyp-main.c

@@ -47,6 +47,8 @@ static DEFINE_PER_CPU(struct pkvm_loaded_state, loaded_state);
 
 DEFINE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params);
 
+struct kvm_iommu_ops kvm_iommu_ops;
+
 void __kvm_hyp_host_forward_smc(struct kvm_cpu_context *host_ctxt);
 
 typedef void (*shadow_entry_exit_handler_fn)(struct kvm_vcpu *, struct kvm_vcpu *);
@@ -906,6 +908,7 @@ static void handle___pkvm_init(struct kvm_cpu_context *host_ctxt)
 	DECLARE_REG(unsigned long, nr_cpus, host_ctxt, 3);
 	DECLARE_REG(unsigned long *, per_cpu_base, host_ctxt, 4);
 	DECLARE_REG(u32, hyp_va_bits, host_ctxt, 5);
+	DECLARE_REG(enum kvm_iommu_driver, iommu_driver, host_ctxt, 6);
 
 	/*
 	 * __pkvm_init() will return only if an error occurred, otherwise it
@@ -913,7 +916,7 @@ static void handle___pkvm_init(struct kvm_cpu_context *host_ctxt)
 	 * with the host context directly.
 	 */
 	cpu_reg(host_ctxt, 1) = __pkvm_init(phys, size, nr_cpus, per_cpu_base,
-					    hyp_va_bits);
+					    hyp_va_bits, iommu_driver);
 }
 
 static void handle___pkvm_cpu_set_vector(struct kvm_cpu_context *host_ctxt)
@@ -1089,6 +1092,8 @@ static void handle_host_smc(struct kvm_cpu_context *host_ctxt)
 	bool handled;
 
 	handled = kvm_host_psci_handler(host_ctxt);
+	if (!handled && kvm_iommu_ops.host_smc_handler)
+		handled = kvm_iommu_ops.host_smc_handler(host_ctxt);
 	if (!handled)
 		handled = kvm_host_ffa_handler(host_ctxt);
 	if (!handled)

arch/arm64/kvm/hyp/nvhe/setup.c

@@ -280,6 +280,16 @@ static int fix_hyp_pgtable_refcnt(void)
 				&walker);
 }
 
+static int select_iommu_ops(enum kvm_iommu_driver driver)
+{
+	switch (driver) {
+	case KVM_IOMMU_DRIVER_NONE:
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
 void __noreturn __pkvm_init_finalise(void)
 {
 	struct kvm_host_data *host_data = this_cpu_ptr(&kvm_host_data);
@@ -309,6 +319,12 @@ void __noreturn __pkvm_init_finalise(void)
 	};
 	pkvm_pgtable.mm_ops = &pkvm_pgtable_mm_ops;
 
+	if (kvm_iommu_ops.init) {
+		ret = kvm_iommu_ops.init();
+		if (ret)
+			goto out;
+	}
+
 	ret = fix_host_ownership();
 	if (ret)
 		goto out;
@@ -337,7 +353,8 @@ out:
 }
 
 int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
-		unsigned long *per_cpu_base, u32 hyp_va_bits)
+		unsigned long *per_cpu_base, u32 hyp_va_bits,
+		enum kvm_iommu_driver iommu_driver)
 {
 	struct kvm_nvhe_init_params *params;
 	void *virt = hyp_phys_to_virt(phys);
@@ -360,6 +377,10 @@ int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
 	if (ret)
 		return ret;
 
+	ret = select_iommu_ops(iommu_driver);
+	if (ret)
+		return ret;
+
 	update_nvhe_init_params();
 
 	/* Jump in the idmap page to switch to the new page-tables */