[PATCH v5 13/36] KVM: arm64: Enable access to sanitized CPU features at EL2

@@ -607,6 +607,7 @@ void check_local_cpu_capabilities(void);
 
 u64 read_sanitised_ftr_reg(u32 id);
 u64 __read_sysreg_by_encoding(u32 sys_id);
+int copy_ftr_reg(u32 id, struct arm64_ftr_reg *dst);
 
 static inline bool cpu_supports_mixed_endian_el0(void)
 {

@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 - Google LLC
+ * Author: Quentin Perret <qperret@google.com>
+ */
+
+#include <asm/cpufeature.h>
+
+#ifndef KVM_HYP_CPU_FTR_REG
+#if defined(__KVM_NVHE_HYPERVISOR__)
+#define KVM_HYP_CPU_FTR_REG(name) extern struct arm64_ftr_reg name
+#else
+#define KVM_HYP_CPU_FTR_REG(name) extern struct arm64_ftr_reg kvm_nvhe_sym(name)
+#endif
+#endif

@@ -751,9 +751,13 @@ void kvm_clr_pmu_events(u32 clr);
 
 void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu);
 void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu);
+
+void setup_kvm_el2_caps(void);
 #else
 static inline void kvm_set_pmu_events(u32 set, struct perf_event_attr *attr) {}
 static inline void kvm_clr_pmu_events(u32 clr) {}
+
+static inline void setup_kvm_el2_caps(void) {}
 #endif
 
 void kvm_vcpu_load_sysregs_vhe(struct kvm_vcpu *vcpu);

@@ -1154,6 +1154,18 @@ u64 read_sanitised_ftr_reg(u32 id)
 }
 EXPORT_SYMBOL_GPL(read_sanitised_ftr_reg);
 
+int copy_ftr_reg(u32 id, struct arm64_ftr_reg *dst)
+{
+	struct arm64_ftr_reg *regp = get_arm64_ftr_reg(id);
+
+	if (!regp)
+		return -EINVAL;
+
+	*dst = *regp;
+
+	return 0;
+}
+
 #define read_sysreg_case(r)	\
 	case r:		val = read_sysreg_s(r); break;
 

@@ -2773,6 +2785,7 @@ void __init setup_cpu_features(void)
 
 	setup_system_capabilities();
 	setup_elf_hwcaps(arm64_elf_hwcaps);
+	setup_kvm_el2_caps();
 
 	if (system_supports_32bit_el0())
 		setup_elf_hwcaps(compat_elf_hwcaps);

@@ -38,3 +38,10 @@ unsigned long __hyp_per_cpu_offset(unsigned int cpu)
 	elf_base = (unsigned long)&__per_cpu_start;
 	return this_cpu_base - elf_base;
 }
+
+/*
+ * Define the CPU feature registers variables that will hold the copies of
+ * the host's sanitized values.
+ */
+#define KVM_HYP_CPU_FTR_REG(name) struct arm64_ftr_reg name
+#include <asm/kvm_cpufeature.h>

@@ -21,6 +21,7 @@
 #include <asm/debug-monitors.h>
 #include <asm/esr.h>
 #include <asm/kvm_arm.h>
+#include <asm/kvm_cpufeature.h>
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_hyp.h>
 #include <asm/kvm_mmu.h>

@@ -2775,3 +2776,21 @@ void kvm_sys_reg_table_init(void)
 	/* Clear all higher bits. */
 	cache_levels &= (1 << (i*3))-1;
 }
+
+#define CPU_FTR_REG_HYP_COPY(id, name) \
+	{ .sys_id = id, .dst = (struct arm64_ftr_reg *)&kvm_nvhe_sym(name) }
+struct __ftr_reg_copy_entry {
+	u32			sys_id;
+	struct arm64_ftr_reg	*dst;
+} hyp_ftr_regs[] __initdata = {
+};
+
+void __init setup_kvm_el2_caps(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(hyp_ftr_regs); i++) {
+		WARN(copy_ftr_reg(hyp_ftr_regs[i].sys_id, hyp_ftr_regs[i].dst),
+		     "%u feature register not found\n", hyp_ftr_regs[i].sys_id);
+	}
+}