[PATCH v2 01/20] KVM: arm64: Refactor idreg caching into dedicated structure
From: Steffen Eiden <seiden@linux.ibm.com>
Date: 2026-08-31 15:01:10
Also in:
kvm, kvmarm, linux-s390, lkml
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
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 <redacted> Signed-off-by: Nina Schoetterl-Glausch <redacted> Signed-off-by: Steffen Eiden <seiden@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