[PATCH v2 06/20] KVM: arm64: Prepare sys_regs.c for sharing with s390

From: Steffen Eiden

Date: Mon Aug 31 2026 - 18:03:11 EST


Prepare sharing of sys_regs.c with s390 by moving functions to another
location inside sys_regs.c. This reduces the number of shared regions.

Signed-off-by: Steffen Eiden <seiden@xxxxxxxxxxxxx>
---
arch/arm64/kvm/sys_regs.c | 100 +++++++++++++++++++-------------------
arch/s390/kvm/arm64/arm.c | 2 +
2 files changed, 52 insertions(+), 50 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 7d0047b542f4..53d096803d9d 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2043,13 +2043,6 @@ static inline bool is_vcpu_ftr_id_reg(u32 id)
return is_feature_id_reg(id) && !is_vm_ftr_id_reg(id);
}

-static inline bool is_aa32_id_reg(u32 id)
-{
- return (sys_reg_Op0(id) == 3 && sys_reg_Op1(id) == 0 &&
- sys_reg_CRn(id) == 0 && sys_reg_CRm(id) >= 1 &&
- sys_reg_CRm(id) <= 3);
-}
-
static unsigned int id_visibility(const struct kvm_vcpu *vcpu,
const struct sys_reg_desc *r)
{
@@ -2065,20 +2058,6 @@ static unsigned int id_visibility(const struct kvm_vcpu *vcpu,
return 0;
}

-static unsigned int aa32_id_visibility(const struct kvm_vcpu *vcpu,
- const struct sys_reg_desc *r)
-{
- /*
- * AArch32 ID registers are UNKNOWN if AArch32 isn't implemented at any
- * EL. Promote to RAZ/WI in order to guarantee consistency between
- * systems.
- */
- if (!kvm_supports_32bit_el0())
- return REG_RAZ | REG_USER_WI;
-
- return id_visibility(vcpu, r);
-}
-
static unsigned int raz_visibility(const struct kvm_vcpu *vcpu,
const struct sys_reg_desc *r)
{
@@ -2099,6 +2078,27 @@ static bool access_id_reg(struct kvm_vcpu *vcpu,
return true;
}

+static unsigned int aa32_id_visibility(const struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *r)
+{
+ /*
+ * AArch32 ID registers are UNKNOWN if AArch32 isn't implemented at any
+ * EL. Promote to RAZ/WI in order to guarantee consistency between
+ * systems.
+ */
+ if (!kvm_supports_32bit_el0())
+ return REG_RAZ | REG_USER_WI;
+
+ return id_visibility(vcpu, r);
+}
+
+static inline bool is_aa32_id_reg(u32 id)
+{
+ return (sys_reg_Op0(id) == 3 && sys_reg_Op1(id) == 0 &&
+ sys_reg_CRn(id) == 0 && sys_reg_CRm(id) >= 1 &&
+ sys_reg_CRm(id) <= 3);
+}
+
/* Visibility overrides for SVE-specific control registers */
static unsigned int sve_visibility(const struct kvm_vcpu *vcpu,
const struct sys_reg_desc *rd)
@@ -2553,29 +2553,6 @@ void kvm_set_vm_id_reg(struct kvm *kvm, u32 reg, u64 val)
*p = val;
}

-static int get_raz_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
- u64 *val)
-{
- *val = 0;
- return 0;
-}
-
-static int set_wi_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
- u64 val)
-{
- return 0;
-}
-
-static bool access_ctr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
- const struct sys_reg_desc *r)
-{
- if (p->is_write)
- return write_to_read_only(vcpu, p, r);
-
- p->regval = kvm_read_vm_id_reg(vcpu->kvm, SYS_CTR_EL0);
- return true;
-}
-
static bool access_clidr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
const struct sys_reg_desc *r)
{
@@ -2684,6 +2661,29 @@ static bool access_ccsidr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
return true;
}

+static int get_raz_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ u64 *val)
+{
+ *val = 0;
+ return 0;
+}
+
+static int set_wi_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ u64 val)
+{
+ return 0;
+}
+
+static bool access_ctr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
+ const struct sys_reg_desc *r)
+{
+ if (p->is_write)
+ return write_to_read_only(vcpu, p, r);
+
+ p->regval = kvm_read_vm_id_reg(vcpu->kvm, SYS_CTR_EL0);
+ return true;
+}
+
static unsigned int mte_visibility(const struct kvm_vcpu *vcpu,
const struct sys_reg_desc *rd)
{
@@ -4855,12 +4855,6 @@ static bool check_sysreg_table(const struct sys_reg_desc *table, unsigned int n,
return true;
}

-int kvm_handle_cp14_load_store(struct kvm_vcpu *vcpu)
-{
- kvm_inject_undefined(vcpu);
- return 1;
-}
-
static void perform_access(struct kvm_vcpu *vcpu,
struct sys_reg_params *params,
const struct sys_reg_desc *r)
@@ -4944,6 +4938,12 @@ static void unhandled_cp_access(struct kvm_vcpu *vcpu,
kvm_inject_undefined(vcpu);
}

+int kvm_handle_cp14_load_store(struct kvm_vcpu *vcpu)
+{
+ kvm_inject_undefined(vcpu);
+ return 1;
+}
+
/**
* kvm_handle_cp_64 -- handles a mrrc/mcrr trap on a guest CP14/CP15 access
* @vcpu: The VCPU pointer
diff --git a/arch/s390/kvm/arm64/arm.c b/arch/s390/kvm/arm64/arm.c
index 3caa72f780a5..2740ee3b703e 100644
--- a/arch/s390/kvm/arm64/arm.c
+++ b/arch/s390/kvm/arm64/arm.c
@@ -9,6 +9,7 @@
#include <linux/kvm_host.h>
#include <linux/cleanup.h>
#include <linux/fpu.h>
+#include <linux/bitfield.h>

#include <asm/access-regs.h>

@@ -25,6 +26,7 @@
#include "trace.h"

static unsigned long system_supported_vcpu_features(void);
+#define read_sanitised_ftr_reg(_id) 0

#define __INCL_GEN_ARM_FILE
#include "generated/arm.inc"
--
2.53.0