From 7a440cc78392c3caf805ef0afc7ead031e4d0830 Mon Sep 17 00:00:00 2001 From: Quentin Perret Date: Fri, 19 Mar 2021 10:01:21 +0000 Subject: [PATCH] KVM: arm64: Enable access to sanitized CPU features at EL2 Introduce the infrastructure in KVM enabling to copy CPU feature registers into EL2-owned data-structures, to allow reading sanitised values directly at EL2 in nVHE. Given that only a subset of these features are being read by the hypervisor, the ones that need to be copied are to be listed under together with the name of the nVHE variable that will hold the copy. This introduces only the infrastructure enabling this copy. The first users will follow shortly. Signed-off-by: Quentin Perret Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20210319100146.1149909-14-qperret@google.com --- arch/arm64/include/asm/cpufeature.h | 1 + arch/arm64/include/asm/kvm_cpufeature.h | 22 ++++++++++++++++++++++ arch/arm64/include/asm/kvm_host.h | 4 ++++ arch/arm64/kernel/cpufeature.c | 13 +++++++++++++ arch/arm64/kvm/sys_regs.c | 19 +++++++++++++++++++ 5 files changed, 59 insertions(+) create mode 100644 arch/arm64/include/asm/kvm_cpufeature.h diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 61177ba..a85cea2 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -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) { diff --git a/arch/arm64/include/asm/kvm_cpufeature.h b/arch/arm64/include/asm/kvm_cpufeature.h new file mode 100644 index 0000000..3d245f9 --- /dev/null +++ b/arch/arm64/include/asm/kvm_cpufeature.h @@ -0,0 +1,22 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2020 - Google LLC + * Author: Quentin Perret + */ + +#ifndef __ARM64_KVM_CPUFEATURE_H__ +#define __ARM64_KVM_CPUFEATURE_H__ + +#include + +#include + +#if defined(__KVM_NVHE_HYPERVISOR__) +#define DECLARE_KVM_HYP_CPU_FTR_REG(name) extern struct arm64_ftr_reg name +#define DEFINE_KVM_HYP_CPU_FTR_REG(name) struct arm64_ftr_reg name +#else +#define DECLARE_KVM_HYP_CPU_FTR_REG(name) extern struct arm64_ftr_reg kvm_nvhe_sym(name) +#define DEFINE_KVM_HYP_CPU_FTR_REG(name) BUILD_BUG() +#endif + +#endif diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 6a2031a..02e172d 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -740,9 +740,13 @@ 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); diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 0660307..6252476 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -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); diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 4f2f1e3..6c5d133 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include #include @@ -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); + } +} -- 2.7.4