[PATCH 1/4] KVM: arm64: add emulation for CTR_EL0 register
Sebastian Ott
sebott at redhat.com
Mon Mar 18 04:16:33 PDT 2024
CTR_EL0 is currently handled as an invariant register, thus
guests will be presented with the host value of that register.
Add emulation for CTR_EL0 and maintain a per vcpu value. The
only thing that is allowed to be changed compared to the host
value is to switch off the DIC bit which describes Icache
invalidation requirements.
Signed-off-by: Sebastian Ott <sebott at redhat.com>
---
arch/arm64/kvm/sys_regs.c | 44 +++++++++++++++++++++++++++++++--------
1 file changed, 35 insertions(+), 9 deletions(-)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 30253bd19917..b2019faa9d73 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1871,10 +1871,42 @@ static bool access_ctr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
if (p->is_write)
return write_to_read_only(vcpu, p, r);
- p->regval = read_sanitised_ftr_reg(SYS_CTR_EL0);
+ p->regval = __vcpu_sys_reg(vcpu, r->reg);
return true;
}
+static u64 reset_ctr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd)
+{
+ u64 val = read_sanitised_ftr_reg(SYS_CTR_EL0);
+
+ __vcpu_sys_reg(vcpu, rd->reg) = val;
+ return __vcpu_sys_reg(vcpu, rd->reg);
+}
+
+static int get_ctr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ u64 *val)
+{
+ *val = __vcpu_sys_reg(vcpu, rd->reg);
+ return 0;
+}
+
+static int set_ctr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ u64 val)
+{
+ u64 ctr_el0 = read_sanitised_ftr_reg(SYS_CTR_EL0);
+
+ if (kvm_vm_has_ran_once(vcpu->kvm) &&
+ val != __vcpu_sys_reg(vcpu, rd->reg))
+ return -EBUSY;
+
+ if (((ctr_el0 & ~CTR_EL0_DIC_MASK) != (val & ~CTR_EL0_DIC_MASK)) ||
+ ((ctr_el0 & CTR_EL0_DIC_MASK) < (val & CTR_EL0_DIC_MASK)))
+ return -EINVAL;
+
+ __vcpu_sys_reg(vcpu, rd->reg) = val;
+ return 0;
+}
+
static bool access_clidr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
const struct sys_reg_desc *r)
{
@@ -2461,7 +2493,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
{ SYS_DESC(SYS_CCSIDR2_EL1), undef_access },
{ SYS_DESC(SYS_SMIDR_EL1), undef_access },
{ SYS_DESC(SYS_CSSELR_EL1), access_csselr, reset_unknown, CSSELR_EL1 },
- { SYS_DESC(SYS_CTR_EL0), access_ctr },
+ { SYS_DESC(SYS_CTR_EL0), access_ctr, .reset = reset_ctr,
+ .get_user = get_ctr, .set_user = set_ctr},
{ SYS_DESC(SYS_SVCR), undef_access },
{ PMU_SYS_REG(PMCR_EL0), .access = access_pmcr, .reset = reset_pmcr,
@@ -3578,18 +3611,11 @@ FUNCTION_INVARIANT(midr_el1)
FUNCTION_INVARIANT(revidr_el1)
FUNCTION_INVARIANT(aidr_el1)
-static u64 get_ctr_el0(struct kvm_vcpu *v, const struct sys_reg_desc *r)
-{
- ((struct sys_reg_desc *)r)->val = read_sanitised_ftr_reg(SYS_CTR_EL0);
- return ((struct sys_reg_desc *)r)->val;
-}
-
/* ->val is filled in by kvm_sys_reg_table_init() */
static struct sys_reg_desc invariant_sys_regs[] __ro_after_init = {
{ SYS_DESC(SYS_MIDR_EL1), NULL, get_midr_el1 },
{ SYS_DESC(SYS_REVIDR_EL1), NULL, get_revidr_el1 },
{ SYS_DESC(SYS_AIDR_EL1), NULL, get_aidr_el1 },
- { SYS_DESC(SYS_CTR_EL0), NULL, get_ctr_el0 },
};
static int get_invariant_sys_reg(u64 id, u64 __user *uaddr)
--
2.42.0
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