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
sysreg file so that guest can read the modified values.
Signed-off-by: zhanghailiang <zhang.zhanghailiang@xxxxxxxxxx>
Signed-off-by: Peng Liang <liangpeng10@xxxxxxxxxx>
---
arch/arm64/kvm/sys_regs.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index a642ecfebe0a..881b66494524 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1263,10 +1263,6 @@ 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,
@@ -1290,9 +1286,15 @@ 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);
+ /* val should be checked in check_user */
+ __vcpu_sys_reg(vcpu, ID_REG_INDEX(reg_id)) = val;
+ }
return 0;
}
--
2.26.2
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