From: Andrew Jones <[email protected]> Since commit 93390c0a1b20 ("arm64: KVM: Hide unsupported AArch64 CPU features from guests") we can hide cpu features from guests. Apply this to a long standing issue where guests see a PMU available, but it's not, because it was not enabled by KVM's userspace.
Signed-off-by: Andrew Jones <[email protected]> Signed-off-by: Christoffer Dall <[email protected]> --- arch/arm64/kvm/sys_regs.c | 35 +++++++++++++++++++++-------------- 1 file changed, 21 insertions(+), 14 deletions(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 1830ebc227d1..503144f13af0 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -881,18 +881,25 @@ static bool access_cntp_cval(struct kvm_vcpu *vcpu, } /* Read a sanitised cpufeature ID register by sys_reg_desc */ -static u64 read_id_reg(struct sys_reg_desc const *r, bool raz) +static u64 read_id_reg(struct kvm_vcpu *vcpu, + struct sys_reg_desc const *r, + bool raz) { u32 id = sys_reg((u32)r->Op0, (u32)r->Op1, (u32)r->CRn, (u32)r->CRm, (u32)r->Op2); u64 val = raz ? 0 : read_sanitised_ftr_reg(id); - if (id == SYS_ID_AA64PFR0_EL1) { + switch (id) { + case SYS_ID_AA64DFR0_EL1: + if (!kvm_arm_pmu_v3_ready(vcpu)) + val &= ~(0xfUL << ID_AA64DFR0_PMUVER_SHIFT); + break; + case SYS_ID_AA64PFR0_EL1: if (val & (0xfUL << ID_AA64PFR0_SVE_SHIFT)) pr_err_once("kvm [%i]: SVE unsupported for guests, suppressing\n", task_pid_nr(current)); - val &= ~(0xfUL << ID_AA64PFR0_SVE_SHIFT); + break; } return val; @@ -908,7 +915,7 @@ static bool __access_id_reg(struct kvm_vcpu *vcpu, if (p->is_write) return write_to_read_only(vcpu, p, r); - p->regval = read_id_reg(r, raz); + p->regval = read_id_reg(vcpu, r, raz); return true; } @@ -937,17 +944,17 @@ static u64 sys_reg_to_index(const struct sys_reg_desc *reg); * are stored, and for set_id_reg() we don't allow the effective value * to be changed. */ -static int __get_id_reg(const struct sys_reg_desc *rd, void __user *uaddr, - bool raz) +static int __get_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, + void __user *uaddr, bool raz) { const u64 id = sys_reg_to_index(rd); - const u64 val = read_id_reg(rd, raz); + const u64 val = read_id_reg(vcpu, rd, raz); return reg_to_user(uaddr, &val, id); } -static int __set_id_reg(const struct sys_reg_desc *rd, void __user *uaddr, - bool raz) +static int __set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, + void __user *uaddr, bool raz) { const u64 id = sys_reg_to_index(rd); int err; @@ -958,7 +965,7 @@ static int __set_id_reg(const struct sys_reg_desc *rd, void __user *uaddr, return err; /* This is what we mean by invariant: you can't change it. */ - if (val != read_id_reg(rd, raz)) + if (val != read_id_reg(vcpu, rd, raz)) return -EINVAL; return 0; @@ -967,25 +974,25 @@ static int __set_id_reg(const struct sys_reg_desc *rd, void __user *uaddr, static int get_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, const struct kvm_one_reg *reg, void __user *uaddr) { - return __get_id_reg(rd, uaddr, false); + return __get_id_reg(vcpu, rd, uaddr, false); } static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, const struct kvm_one_reg *reg, void __user *uaddr) { - return __set_id_reg(rd, uaddr, false); + return __set_id_reg(vcpu, rd, uaddr, false); } static int get_raz_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, const struct kvm_one_reg *reg, void __user *uaddr) { - return __get_id_reg(rd, uaddr, true); + return __get_id_reg(vcpu, rd, uaddr, true); } static int set_raz_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, const struct kvm_one_reg *reg, void __user *uaddr) { - return __set_id_reg(rd, uaddr, true); + return __set_id_reg(vcpu, rd, uaddr, true); } /* sys_reg_desc initialiser for known cpufeature ID registers */ -- 2.14.2 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
