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@xxxxxxxxxx>
Signed-off-by: Peng Liang <liangpeng10@xxxxxxxxxx>
---
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
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