[PATCH v2 01/20] KVM: arm64: Refactor idreg caching into dedicated structure
Steffen Eiden
seiden at linux.ibm.com
Mon Aug 31 07:55:16 PDT 2026
Move VM-wide ID register emulation fields from struct kvm_arch into a
new struct kvm_vm_id_regs to prepare future sharing of these fields and
functions using them. Update all users to use the new structure. No
functional changes.
Co-developed-by: Nina Schoetterl-Glausch <nsg at linux.ibm.com>
Signed-off-by: Nina Schoetterl-Glausch <nsg at linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden at linux.ibm.com>
---
arch/arm64/include/asm/kvm_host.h | 50 ++++++++++++++++--------------
arch/arm64/kvm/config.c | 2 +-
arch/arm64/kvm/hyp/nvhe/pkvm.c | 7 +++--
arch/arm64/kvm/hyp/nvhe/sys_regs.c | 4 +--
arch/arm64/kvm/sys_regs.c | 2 +-
5 files changed, 35 insertions(+), 30 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index a8ddce3921b8..f9e90ef9ee4b 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -349,6 +349,25 @@ enum fgt_group_id {
__NR_FGT_GROUP_IDS__
};
+struct kvm_vm_id_regs {
+ /*
+ * Emulated CPU ID registers per VM
+ * (Op0, Op1, CRn, CRm, Op2) of the ID registers to be saved in it
+ * is (3, 0, 0, crm, op2), where 1<=crm<8, 0<=op2<8.
+ *
+ * These emulated idregs are VM-wide, but accessed from the context of a vCPU.
+ * Atomic access to multiple idregs are guarded by kvm_arch.config_lock.
+ */
+#define IDREG_IDX(id) (((sys_reg_CRm(id) - 1) << 3) | sys_reg_Op2(id))
+#define KVM_ARM_ID_REG_NUM (IDREG_IDX(sys_reg(3, 0, 0, 7, 7)) + 1)
+ u64 ftr_reg[KVM_ARM_ID_REG_NUM];
+
+ u64 midr_el1;
+ u64 revidr_el1;
+ u64 aidr_el1;
+ u64 ctr_el0;
+};
+
struct kvm_arch {
struct kvm_s2_mmu mmu;
@@ -408,22 +427,7 @@ struct kvm_arch {
struct kvm_smccc_features smccc_feat;
struct maple_tree smccc_filter;
- /*
- * Emulated CPU ID registers per VM
- * (Op0, Op1, CRn, CRm, Op2) of the ID registers to be saved in it
- * is (3, 0, 0, crm, op2), where 1<=crm<8, 0<=op2<8.
- *
- * These emulated idregs are VM-wide, but accessed from the context of a vCPU.
- * Atomic access to multiple idregs are guarded by kvm_arch.config_lock.
- */
-#define IDREG_IDX(id) (((sys_reg_CRm(id) - 1) << 3) | sys_reg_Op2(id))
-#define KVM_ARM_ID_REG_NUM (IDREG_IDX(sys_reg(3, 0, 0, 7, 7)) + 1)
- u64 id_regs[KVM_ARM_ID_REG_NUM];
-
- u64 midr_el1;
- u64 revidr_el1;
- u64 aidr_el1;
- u64 ctr_el0;
+ struct kvm_vm_id_regs id_regs;
/* Masks for VNCR-backed and general EL2 sysregs */
struct kvm_sysreg_masks *sysreg_masks;
@@ -1563,19 +1567,19 @@ static inline void kvm_hyp_reserve(void) { }
void kvm_arm_vcpu_power_off(struct kvm_vcpu *vcpu);
bool kvm_arm_vcpu_stopped(struct kvm_vcpu *vcpu);
-static inline u64 *__vm_id_reg(struct kvm_arch *ka, u32 reg)
+static inline u64 *__vm_id_reg(struct kvm_vm_id_regs *id_regs, u32 reg)
{
switch (reg) {
case sys_reg(3, 0, 0, 1, 0) ... sys_reg(3, 0, 0, 7, 7):
- return &ka->id_regs[IDREG_IDX(reg)];
+ return &id_regs->ftr_reg[IDREG_IDX(reg)];
case SYS_CTR_EL0:
- return &ka->ctr_el0;
+ return &id_regs->ctr_el0;
case SYS_MIDR_EL1:
- return &ka->midr_el1;
+ return &id_regs->midr_el1;
case SYS_REVIDR_EL1:
- return &ka->revidr_el1;
+ return &id_regs->revidr_el1;
case SYS_AIDR_EL1:
- return &ka->aidr_el1;
+ return &id_regs->aidr_el1;
default:
WARN_ON_ONCE(1);
return NULL;
@@ -1583,7 +1587,7 @@ static inline u64 *__vm_id_reg(struct kvm_arch *ka, u32 reg)
}
#define kvm_read_vm_id_reg(kvm, reg) \
- ({ u64 __val = *__vm_id_reg(&(kvm)->arch, reg); __val; })
+ ({ u64 __val = *__vm_id_reg(&(kvm)->arch.id_regs, reg); __val; })
void kvm_set_vm_id_reg(struct kvm *kvm, u32 reg, u64 val);
diff --git a/arch/arm64/kvm/config.c b/arch/arm64/kvm/config.c
index 1053676551af..de56656237f4 100644
--- a/arch/arm64/kvm/config.c
+++ b/arch/arm64/kvm/config.c
@@ -1410,7 +1410,7 @@ void __init check_feature_map(void)
static bool idreg_feat_match(struct kvm *kvm, const struct reg_bits_to_feat_map *map)
{
- u64 regval = kvm->arch.id_regs[map->regidx];
+ u64 regval = kvm->arch.id_regs.ftr_reg[map->regidx];
u64 regfld = (regval >> map->shift) & GENMASK(map->width - 1, 0);
if (map->sign) {
diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c
index 459bd9eb7e4b..bb11561de05e 100644
--- a/arch/arm64/kvm/hyp/nvhe/pkvm.c
+++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c
@@ -343,7 +343,7 @@ static void pkvm_init_features_from_host(struct pkvm_hyp_vm *hyp_vm, const struc
DECLARE_BITMAP(allowed_features, KVM_VCPU_MAX_FEATURES);
/* CTR_EL0 is always under host control, even for protected VMs. */
- hyp_vm->kvm.arch.ctr_el0 = host_kvm->arch.ctr_el0;
+ hyp_vm->kvm.arch.id_regs.ctr_el0 = host_kvm->arch.id_regs.ctr_el0;
/* Preserve the vgic model so that GICv3 emulation works */
hyp_vm->kvm.arch.vgic.vgic_model = host_kvm->arch.vgic.vgic_model;
@@ -358,7 +358,7 @@ static void pkvm_init_features_from_host(struct pkvm_hyp_vm *hyp_vm, const struc
KVM_VCPU_MAX_FEATURES);
if (test_bit(KVM_ARCH_FLAG_WRITABLE_IMP_ID_REGS, &host_arch_flags))
- hyp_vm->kvm.arch.midr_el1 = host_kvm->arch.midr_el1;
+ hyp_vm->kvm.arch.id_regs.midr_el1 = host_kvm->arch.id_regs.midr_el1;
return;
}
@@ -492,7 +492,8 @@ static int vm_copy_id_regs(struct pkvm_hyp_vcpu *hyp_vcpu)
if (test_and_set_bit(KVM_ARCH_FLAG_ID_REGS_INITIALIZED, &kvm->arch.flags))
return 0;
- memcpy(kvm->arch.id_regs, host_kvm->arch.id_regs, sizeof(kvm->arch.id_regs));
+ memcpy(kvm->arch.id_regs.ftr_reg, host_kvm->arch.id_regs.ftr_reg,
+ sizeof(kvm->arch.id_regs.ftr_reg));
return 0;
}
diff --git a/arch/arm64/kvm/hyp/nvhe/sys_regs.c b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
index 8758c6801776..3e70b71d8f4f 100644
--- a/arch/arm64/kvm/hyp/nvhe/sys_regs.c
+++ b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
@@ -293,7 +293,7 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu,
return 0;
if (reg >= sys_reg(3, 0, 0, 1, 0) && reg <= sys_reg(3, 0, 0, 7, 7))
- return kvm->arch.id_regs[IDREG_IDX(reg)];
+ return kvm->arch.id_regs.ftr_reg[IDREG_IDX(reg)];
return 0;
}
@@ -544,7 +544,7 @@ void kvm_init_pvm_id_regs(struct kvm_vcpu *vcpu)
* for protected VMs.
*/
for (r = sys_reg(3, 0, 0, 4, 0); r <= sys_reg(3, 0, 0, 7, 7); r += sys_reg(0, 0, 0, 0, 1))
- ka->id_regs[IDREG_IDX(r)] = pvm_calc_id_reg(vcpu, r);
+ ka->id_regs.ftr_reg[IDREG_IDX(r)] = pvm_calc_id_reg(vcpu, r);
set_bit(KVM_ARCH_FLAG_ID_REGS_INITIALIZED, &kvm->arch.flags);
}
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 44aae52c473d..06dc8ec7a883 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2543,7 +2543,7 @@ static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
void kvm_set_vm_id_reg(struct kvm *kvm, u32 reg, u64 val)
{
- u64 *p = __vm_id_reg(&kvm->arch, reg);
+ u64 *p = __vm_id_reg(&kvm->arch.id_regs, reg);
lockdep_assert_held(&kvm->arch.config_lock);
--
2.53.0
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