KVM/arm64 fixes for 5.16, take #1

- Fix the host S2 finalization by solely iterating over the memblocks
   instead of the whole IPA space
 
 - Tighten the return value of kvm_vcpu_preferred_target() now that
   32bit support is long gone
 
 - Make sure the extraction of ESR_ELx.EC is limited to the architected
   bits
 
 - Comment fixups
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Merge tag 'kvmarm-fixes-5.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into kvm-master

KVM/arm64 fixes for 5.16, take #1

- Fix the host S2 finalization by solely iterating over the memblocks
  instead of the whole IPA space

- Tighten the return value of kvm_vcpu_preferred_target() now that
  32bit support is long gone

- Make sure the extraction of ESR_ELx.EC is limited to the architected
  bits

- Comment fixups

arch/arm64/include/asm/esr.h

@@ -68,6 +68,7 @@
 #define ESR_ELx_EC_MAX		(0x3F)
 
 #define ESR_ELx_EC_SHIFT	(26)
+#define ESR_ELx_EC_WIDTH	(6)
 #define ESR_ELx_EC_MASK		(UL(0x3F) << ESR_ELx_EC_SHIFT)
 #define ESR_ELx_EC(esr)		(((esr) & ESR_ELx_EC_MASK) >> ESR_ELx_EC_SHIFT)
 

arch/arm64/include/asm/kvm_host.h

@@ -584,7 +584,7 @@ struct kvm_vcpu_stat {
 	u64 exits;
 };
 
-int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init);
+void kvm_vcpu_preferred_target(struct kvm_vcpu_init *init);
 unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu);
 int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *indices);
 int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);

arch/arm64/kvm/arm.c

@@ -1389,12 +1389,9 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		return kvm_vm_ioctl_set_device_addr(kvm, &dev_addr);
 	}
 	case KVM_ARM_PREFERRED_TARGET: {
-		int err;
 		struct kvm_vcpu_init init;
 
-		err = kvm_vcpu_preferred_target(&init);
-		if (err)
-			return err;
+		kvm_vcpu_preferred_target(&init);
 
 		if (copy_to_user(argp, &init, sizeof(init)))
 			return -EFAULT;

arch/arm64/kvm/guest.c

@@ -869,13 +869,10 @@ u32 __attribute_const__ kvm_target_cpu(void)
 	return KVM_ARM_TARGET_GENERIC_V8;
 }
 
-int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init)
+void kvm_vcpu_preferred_target(struct kvm_vcpu_init *init)
 {
 	u32 target = kvm_target_cpu();
 
-	if (target < 0)
-		return -ENODEV;
-
 	memset(init, 0, sizeof(*init));
 
 	/*
@@ -885,8 +882,6 @@ int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init)
 	 * target type.
 	 */
 	init->target = (__u32)target;
-
-	return 0;
 }
 
 int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)

arch/arm64/kvm/hyp/hyp-entry.S

@@ -44,7 +44,7 @@
 el1_sync:				// Guest trapped into EL2
 
 	mrs	x0, esr_el2
-	lsr	x0, x0, #ESR_ELx_EC_SHIFT
+	ubfx	x0, x0, #ESR_ELx_EC_SHIFT, #ESR_ELx_EC_WIDTH
 	cmp	x0, #ESR_ELx_EC_HVC64
 	ccmp	x0, #ESR_ELx_EC_HVC32, #4, ne
 	b.ne	el1_trap

arch/arm64/kvm/hyp/nvhe/host.S

@@ -141,7 +141,7 @@ SYM_FUNC_END(__host_hvc)
 .L__vect_start\@:
 	stp	x0, x1, [sp, #-16]!
 	mrs	x0, esr_el2
-	lsr	x0, x0, #ESR_ELx_EC_SHIFT
+	ubfx	x0, x0, #ESR_ELx_EC_SHIFT, #ESR_ELx_EC_WIDTH
 	cmp	x0, #ESR_ELx_EC_HVC64
 	b.eq	__host_hvc
 	b	__host_exit

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

@@ -178,7 +178,7 @@ static int finalize_host_mappings_walker(u64 addr, u64 end, u32 level,
 
 	phys = kvm_pte_to_phys(pte);
 	if (!addr_is_memory(phys))
-		return 0;
+		return -EINVAL;
 
 	/*
 	 * Adjust the host stage-2 mappings to match the ownership attributes
@@ -207,8 +207,18 @@ static int finalize_host_mappings(void)
 		.cb	= finalize_host_mappings_walker,
 		.flags	= KVM_PGTABLE_WALK_LEAF,
 	};
+	int i, ret;
 
-	return kvm_pgtable_walk(&pkvm_pgtable, 0, BIT(pkvm_pgtable.ia_bits), &walker);
+	for (i = 0; i < hyp_memblock_nr; i++) {
+		struct memblock_region *reg = &hyp_memory[i];
+		u64 start = (u64)hyp_phys_to_virt(reg->base);
+
+		ret = kvm_pgtable_walk(&pkvm_pgtable, start, reg->size, &walker);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
 }
 
 void __noreturn __pkvm_init_finalise(void)

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

@@ -474,7 +474,7 @@ bool kvm_handle_pvm_sysreg(struct kvm_vcpu *vcpu, u64 *exit_code)
 	return true;
 }
 
-/**
+/*
  * Handler for protected VM restricted exceptions.
  *
  * Inject an undefined exception into the guest and return true to indicate that