From: Peng Liang <liangpeng10@huawei.com> hulk inclusion category: feature bugzilla: NA CVE: NA It's time to make ID registers configurable. When userspace (but not guest) want to set the values of ID registers, save the value in kvm_arch_vcpu so that guest can read the modified values. Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com> Signed-off-by: Peng Liang <liangpeng10@huawei.com> Reviewed-by: Xiangyou Xie <xiexiangyou@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- arch/arm64/kvm/sys_regs.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index ccb868dc0efa7..29496548c56b9 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1053,6 +1053,17 @@ static u64 kvm_get_id_reg(struct kvm_vcpu *vcpu, u64 id) return ri->sys_val; } +static void kvm_set_id_reg(struct kvm_vcpu *vcpu, u64 id, u64 value) +{ + struct id_reg_info *ri = kvm_id_reg(vcpu, id); + + if (!ri) { + WARN_ON(1); + return; + } + ri->sys_val = value; +} + /* Read a sanitised cpufeature ID register by sys_reg_desc */ static u64 read_id_reg(struct kvm_vcpu *vcpu, struct sys_reg_desc const *r, bool raz) @@ -1110,10 +1121,6 @@ static u64 sys_reg_to_index(const struct sys_reg_desc *reg); /* * cpufeature ID register user accessors - * - * For now, these registers are immutable for userspace, so no values - * are stored, and for set_id_reg() we don't allow the effective value - * to be changed. */ static int __get_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, void __user *uaddr, @@ -1137,9 +1144,14 @@ static int __set_id_reg(struct kvm_vcpu *vcpu, if (err) return err; - /* This is what we mean by invariant: you can't change it. */ - if (val != read_id_reg(vcpu, rd, raz)) - return -EINVAL; + if (raz) { + if (val != read_id_reg(vcpu, rd, raz)) + return -EINVAL; + } else { + u32 reg_id = sys_reg((u32)rd->Op0, (u32)rd->Op1, (u32)rd->CRn, + (u32)rd->CRm, (u32)rd->Op2); + kvm_set_id_reg(vcpu, reg_id, val); + } return 0; } -- 2.25.1