Merge branch kvm-arm64/sysreg-cleanup-5.20 into kvmarm-master/next

* kvm-arm64/sysreg-cleanup-5.20:
  : .
  : Long overdue cleanup of the sysreg userspace access,
  : with extra scrubbing on the vgic side of things.
  : From the cover letter:
  :
  : "Schspa Shi recently reported[1] that some of the vgic code interacting
  : with userspace was reading uninitialised stack memory, and although
  : that read wasn't used any further, it prompted me to revisit this part
  : of the code.
  :
  : Needless to say, this area of the kernel is pretty crufty, and shows a
  : bunch of issues in other parts of the KVM/arm64 infrastructure. This
  : series tries to remedy a bunch of them:
  :
  : - Sanitise the way we deal with sysregs from userspace: at the moment,
  :   each and every .set_user/.get_user callback has to implement its own
  :   userspace accesses (directly or indirectly). It'd be much better if
  :   that was centralised so that we can reason about it.
  :
  : - Enforce that all AArch64 sysregs are 64bit. Always. This was sort of
  :   implied by the code, but it took some effort to convince myself that
  :   this was actually the case.
  :
  : - Move the vgic-v3 sysreg userspace accessors to the userspace
  :   callbacks instead of hijacking the vcpu trap callback. This allows
  :   us to reuse the sysreg infrastructure.
  :
  : - Consolidate userspace accesses for both GICv2, GICv3 and common code
  :   as much as possible.
  :
  : - Cleanup a bunch of not-very-useful helpers, tidy up some of the code
  :   as we touch it.
  :
  : [1] https://lore.kernel.org/r/m2h740zz1i.fsf@gmail.com"
  : .
  KVM: arm64: Get rid or outdated comments
  KVM: arm64: Descope kvm_arm_sys_reg_{get,set}_reg()
  KVM: arm64: Get rid of find_reg_by_id()
  KVM: arm64: vgic: Tidy-up calls to vgic_{get,set}_common_attr()
  KVM: arm64: vgic: Consolidate userspace access for base address setting
  KVM: arm64: vgic-v2: Add helper for legacy dist/cpuif base address setting
  KVM: arm64: vgic: Use {get,put}_user() instead of copy_{from.to}_user
  KVM: arm64: vgic-v2: Consolidate userspace access for MMIO registers
  KVM: arm64: vgic-v3: Consolidate userspace access for MMIO registers
  KVM: arm64: vgic-v3: Use u32 to manage the line level from userspace
  KVM: arm64: vgic-v3: Convert userspace accessors over to FIELD_GET/FIELD_PREP
  KVM: arm64: vgic-v3: Make the userspace accessors use sysreg API
  KVM: arm64: vgic-v3: Push user access into vgic_v3_cpu_sysregs_uaccess()
  KVM: arm64: vgic-v3: Simplify vgic_v3_has_cpu_sysregs_attr()
  KVM: arm64: Get rid of reg_from/to_user()
  KVM: arm64: Consolidate sysreg userspace accesses
  KVM: arm64: Rely on index_to_param() for size checks on userspace access
  KVM: arm64: Introduce generic get_user/set_user helpers for system registers
  KVM: arm64: Reorder handling of invariant sysregs from userspace
  KVM: arm64: Add get_reg_by_id() as a sys_reg_desc retrieving helper
Signed-off-by: Marc Zyngier <maz@kernel.org>

arch/arm64/include/asm/kvm_host.h

@@ -714,8 +714,6 @@ int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);
 
 unsigned long kvm_arm_num_sys_reg_descs(struct kvm_vcpu *vcpu);
 int kvm_arm_copy_sys_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices);
-int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *);
-int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *);
 
 int __kvm_arm_vcpu_get_events(struct kvm_vcpu *vcpu,
 			      struct kvm_vcpu_events *events);

arch/arm64/kvm/arm.c

@@ -1420,18 +1420,11 @@ void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
 static int kvm_vm_ioctl_set_device_addr(struct kvm *kvm,
 					struct kvm_arm_device_addr *dev_addr)
 {
-	unsigned long dev_id, type;
-
-	dev_id = (dev_addr->id & KVM_ARM_DEVICE_ID_MASK) >>
-		KVM_ARM_DEVICE_ID_SHIFT;
-	type = (dev_addr->id & KVM_ARM_DEVICE_TYPE_MASK) >>
-		KVM_ARM_DEVICE_TYPE_SHIFT;
-
-	switch (dev_id) {
+	switch (FIELD_GET(KVM_ARM_DEVICE_ID_MASK, dev_addr->id)) {
 	case KVM_ARM_DEVICE_VGIC_V2:
 		if (!vgic_present)
 			return -ENXIO;
-		return kvm_vgic_addr(kvm, type, &dev_addr->addr, true);
+		return kvm_set_legacy_vgic_v2_addr(kvm, dev_addr);
 	default:
 		return -ENODEV;
 	}

arch/arm64/kvm/sys_regs.h

@@ -75,9 +75,9 @@ struct sys_reg_desc {
 
 	/* Custom get/set_user functions, fallback to generic if NULL */
 	int (*get_user)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
-			const struct kvm_one_reg *reg, void __user *uaddr);
+			u64 *val);
 	int (*set_user)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
-			const struct kvm_one_reg *reg, void __user *uaddr);
+			u64 val);
 
 	/* Return mask of REG_* runtime visibility overrides */
 	unsigned int (*visibility)(const struct kvm_vcpu *vcpu,
@@ -190,11 +190,17 @@ find_reg(const struct sys_reg_params *params, const struct sys_reg_desc table[],
 	return __inline_bsearch((void *)pval, table, num, sizeof(table[0]), match_sys_reg);
 }
 
-const struct sys_reg_desc *find_reg_by_id(u64 id,
-					  struct sys_reg_params *params,
+const struct sys_reg_desc *get_reg_by_id(u64 id,
 					 const struct sys_reg_desc table[],
 					 unsigned int num);
 
+int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *);
+int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *);
+int kvm_sys_reg_get_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
+			 const struct sys_reg_desc table[], unsigned int num);
+int kvm_sys_reg_set_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
+			 const struct sys_reg_desc table[], unsigned int num);
+
 #define AA32(_x)	.aarch32_map = AA32_##_x
 #define Op0(_x) 	.Op0 = _x
 #define Op1(_x) 	.Op1 = _x

arch/arm64/kvm/vgic/vgic-mmio-v3.c

@@ -986,12 +986,8 @@ int vgic_v3_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr)
 		iodev.base_addr = 0;
 		break;
 	}
-	case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS: {
-		u64 reg, id;
-
-		id = (attr->attr & KVM_DEV_ARM_VGIC_SYSREG_INSTR_MASK);
-		return vgic_v3_has_cpu_sysregs_attr(vcpu, 0, id, &reg);
-	}
+	case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS:
+		return vgic_v3_has_cpu_sysregs_attr(vcpu, attr);
 	default:
 		return -ENXIO;
 	}
@@ -1158,7 +1154,7 @@ int vgic_v3_redist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
 }
 
 int vgic_v3_line_level_info_uaccess(struct kvm_vcpu *vcpu, bool is_write,
-				    u32 intid, u64 *val)
+				    u32 intid, u32 *val)
 {
 	if (intid % 32)
 		return -EINVAL;

arch/arm64/kvm/vgic/vgic-mmio.c

@@ -775,10 +775,10 @@ void vgic_mmio_write_config(struct kvm_vcpu *vcpu,
 	}
 }
 
-u64 vgic_read_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid)
+u32 vgic_read_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid)
 {
 	int i;
-	u64 val = 0;
+	u32 val = 0;
 	int nr_irqs = vcpu->kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS;
 
 	for (i = 0; i < 32; i++) {
@@ -798,7 +798,7 @@ u64 vgic_read_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid)
 }
 
 void vgic_write_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid,
-				    const u64 val)
+				    const u32 val)
 {
 	int i;
 	int nr_irqs = vcpu->kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS;

arch/arm64/kvm/vgic/vgic-mmio.h

@@ -207,10 +207,10 @@ void vgic_mmio_write_config(struct kvm_vcpu *vcpu,
 int vgic_uaccess(struct kvm_vcpu *vcpu, struct vgic_io_device *dev,
 		 bool is_write, int offset, u32 *val);
 
-u64 vgic_read_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid);
+u32 vgic_read_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid);
 
 void vgic_write_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid,
-				    const u64 val);
+				    const u32 val);
 
 unsigned int vgic_v2_init_dist_iodev(struct vgic_io_device *dev);
 

arch/arm64/kvm/vgic/vgic.h

@@ -245,12 +245,11 @@ int vgic_v3_dist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
 			 int offset, u32 *val);
 int vgic_v3_redist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
 			 int offset, u32 *val);
-int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu, bool is_write,
-			 u64 id, u64 *val);
-int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, bool is_write, u64 id,
-				u64 *reg);
+int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu,
+				struct kvm_device_attr *attr, bool is_write);
+int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr);
 int vgic_v3_line_level_info_uaccess(struct kvm_vcpu *vcpu, bool is_write,
-				    u32 intid, u64 *val);
+				    u32 intid, u32 *val);
 int kvm_register_vgic_device(unsigned long type);
 void vgic_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
 void vgic_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);

include/kvm/arm_vgic.h

@@ -364,7 +364,7 @@ struct vgic_cpu {
 extern struct static_key_false vgic_v2_cpuif_trap;
 extern struct static_key_false vgic_v3_cpuif_trap;
 
-int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write);
+int kvm_set_legacy_vgic_v2_addr(struct kvm *kvm, struct kvm_arm_device_addr *dev_addr);
 void kvm_vgic_early_init(struct kvm *kvm);
 int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu);
 int kvm_vgic_create(struct kvm *kvm, u32 type);