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 <[email protected]> Signed-off-by: Peng Liang <[email protected]> --- arch/arm64/kvm/sys_regs.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 776c2757a01e..f98635489966 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1111,6 +1111,14 @@ 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); + + BUG_ON(!ri); + 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) @@ -1252,10 +1260,6 @@ static int set_id_aa64zfr0_el1(struct kvm_vcpu *vcpu, /* * 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, @@ -1279,9 +1283,14 @@ 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; } -- 2.18.4 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
