Introduce id_regs[] in kvm_arch as a storage of guest's ID registers, and save ID registers' sanitized value in the array at KVM_CREATE_VM. Use the saved ones when ID registers are read by the guest or userspace (via KVM_GET_ONE_REG). No functional change intended. Co-developed-by: Reiji Watanabe <reijiw@xxxxxxxxxx> Signed-off-by: Reiji Watanabe <reijiw@xxxxxxxxxx> Signed-off-by: Jing Zhang <jingzhangos@xxxxxxxxxx> --- arch/arm64/include/asm/kvm_host.h | 21 +++++++++++++ arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/id_regs.c | 49 +++++++++++++++++++++++++------ arch/arm64/kvm/sys_regs.c | 2 +- arch/arm64/kvm/sys_regs.h | 1 + 5 files changed, 64 insertions(+), 10 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index a8e2c52b44aa..3b8a2cc0c7cd 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -177,6 +177,22 @@ struct kvm_smccc_features { unsigned long vendor_hyp_bmap; }; +/* + * Emualted CPU ID registers per VM + * (Op0, Op1, CRn, CRm, Op2) of the ID registers to be saved in it + * is (3, 0, 0, crm, op2), where 1<=crm<8, 0<=op2<8. + * + * These emulated idregs are VM-wide, but accessed from the context of a vCPU. + * Updating multiple id regs with dependencies needs to be guarded by + * kvm_arch.config_lock. + */ +#define KVM_ARM_ID_REG_NUM 56 +#define IDREG_IDX(id) (((sys_reg_CRm(id) - 1) << 3) | sys_reg_Op2(id)) +#define IDREG(kvm, id) kvm->arch.idregs.regs[IDREG_IDX(id)] +struct kvm_idregs { + u64 regs[KVM_ARM_ID_REG_NUM]; +}; + typedef unsigned int pkvm_handle_t; struct kvm_protected_vm { @@ -250,6 +266,9 @@ struct kvm_arch { /* Hypercall features firmware registers' descriptor */ struct kvm_smccc_features smccc_feat; + /* Emulated CPU ID registers */ + struct kvm_idregs idregs; + /* * For an untrusted host VM, 'pkvm.handle' is used to lookup * the associated pKVM instance in the hypervisor. @@ -1025,6 +1044,8 @@ long kvm_vm_ioctl_mte_copy_tags(struct kvm *kvm, int kvm_vm_ioctl_set_counter_offset(struct kvm *kvm, struct kvm_arm_counter_offset *offset); +void kvm_arm_init_id_regs(struct kvm *kvm); + /* Guest/host FPSIMD coordination helpers */ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu); void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu); diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 0e5a3ff8cc5a..571e24124a95 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -165,6 +165,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) set_default_spectre(kvm); kvm_arm_init_hypercalls(kvm); + kvm_arm_init_id_regs(kvm); /* * Initialise the default PMUver before there is a chance to diff --git a/arch/arm64/kvm/id_regs.c b/arch/arm64/kvm/id_regs.c index 638c0f8e4cd2..77f945c78d47 100644 --- a/arch/arm64/kvm/id_regs.c +++ b/arch/arm64/kvm/id_regs.c @@ -52,16 +52,9 @@ static u8 pmuver_to_perfmon(u8 pmuver) } } -/* Read a sanitised cpufeature ID register by sys_reg_desc */ -static u64 read_id_reg(const struct kvm_vcpu *vcpu, struct sys_reg_desc const *r) +u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id) { - u32 id = reg_to_encoding(r); - u64 val; - - if (sysreg_visible_as_raz(vcpu, r)) - return 0; - - val = read_sanitised_ftr_reg(id); + u64 val = IDREG(vcpu->kvm, id); switch (id) { case SYS_ID_AA64PFR0_EL1: @@ -126,6 +119,14 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu, struct sys_reg_desc const *r return val; } +static u64 read_id_reg(const struct kvm_vcpu *vcpu, struct sys_reg_desc const *r) +{ + if (sysreg_visible_as_raz(vcpu, r)) + return 0; + + return kvm_arm_read_id_reg(vcpu, reg_to_encoding(r)); +} + /* cpufeature ID register access trap handlers */ static bool access_id_reg(struct kvm_vcpu *vcpu, @@ -494,3 +495,33 @@ int kvm_arm_walk_id_regs(struct kvm_vcpu *vcpu, u64 __user *uind) } return total; } + +/* + * Set the guest's ID registers that are defined in id_reg_descs[] + * with ID_SANITISED() to the host's sanitized value. + */ +void kvm_arm_init_id_regs(struct kvm *kvm) +{ + int i; + u32 id; + u64 val; + + for (i = 0; i < ARRAY_SIZE(id_reg_descs); i++) { + id = reg_to_encoding(&id_reg_descs[i]); + if (WARN_ON_ONCE(!is_id_reg(id))) + /* Shouldn't happen */ + continue; + + /* + * Some hidden ID registers which are not in arm64_ftr_regs[] + * would cause warnings from read_sanitised_ftr_reg(). + * Skip those ID registers to avoid the warnings. + */ + if (id_reg_descs[i].visibility == raz_visibility) + /* Hidden or reserved ID register */ + continue; + + val = read_sanitised_ftr_reg(id); + IDREG(kvm, id) = val; + } +} diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 40be494391fd..3af9f85aa976 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -364,7 +364,7 @@ static bool trap_loregion(struct kvm_vcpu *vcpu, struct sys_reg_params *p, const struct sys_reg_desc *r) { - u64 val = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1); + u64 val = kvm_arm_read_id_reg(vcpu, SYS_ID_AA64MMFR1_EL1); u32 sr = reg_to_encoding(r); if (!(val & (0xfUL << ID_AA64MMFR1_EL1_LO_SHIFT))) { diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h index 2f7750153f8e..326ca28c1117 100644 --- a/arch/arm64/kvm/sys_regs.h +++ b/arch/arm64/kvm/sys_regs.h @@ -247,6 +247,7 @@ int kvm_arm_get_id_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg); int kvm_arm_set_id_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg); bool kvm_arm_check_idreg_table(void); int kvm_arm_walk_id_regs(struct kvm_vcpu *vcpu, u64 __user *uind); +u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id); #define AA32(_x) .aarch32_map = AA32_##_x #define Op0(_x) .Op0 = _x -- 2.40.0.348.gf938b09366-goog