[PATCH v2 21/28] KVM: s390: arm64: Introduce host definitions

Steffen Eiden
2026-04-28T15:57:40Z

Add all basic definitions the arm on s390 KVM host requires.
Including, but not limited to:
- struct kvm*arch definitions
- various functions (to be implemented in the following patches)
- various defines required to run arm64 guests

Co-developed-by: Andreas Grapentin <gra@linux.ibm.com>
Signed-off-by: Andreas Grapentin <gra@linux.ibm.com>
Co-developed-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Signed-off-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
---
arch/s390/include/asm/kvm.h | 6 +
arch/s390/include/asm/kvm_host.h | 9 ++
arch/s390/include/asm/kvm_host_arm64.h | 202 +++++++++++++++++++++++++
3 files changed, 217 insertions(+)
create mode 100644 arch/s390/include/asm/kvm.h
create mode 100644 arch/s390/include/asm/kvm_host_arm64.h

diff --git a/arch/s390/include/asm/kvm.h b/arch/s390/include/asm/kvm.h
new file mode 100644
index 000000000000..d9e727d2378c
--- /dev/null
+++ b/arch/s390/include/asm/kvm.h
@@ -0,0 +1,6 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifdef KVM_S390_ARM64
+#include <uapi/arch/arm64/asm/kvm.h>
+#else
+#include <uapi/asm/kvm.h>
+#endif
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 1c20168a3ef5..0330d3e503d8 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -3,7 +3,16 @@
#ifndef ASM_KVM_HOST_H
#define ASM_KVM_HOST_H

+#ifdef KVM_S390_ARM64
+#include <asm/kvm_host_arm64.h>
+#else
#include <asm/kvm_host_s390.h>
+#endif
+
+static inline bool kvm_arch_pmi_in_guest(struct kvm_vcpu *vcpu)
+{
+ return false;
+}

#define PGM_PROTECTION 0x04
#define PGM_ADDRESSING 0x05
diff --git a/arch/s390/include/asm/kvm_host_arm64.h b/arch/s390/include/asm/kvm_host_arm64.h
new file mode 100644
index 000000000000..08fbb2a75778
--- /dev/null
+++ b/arch/s390/include/asm/kvm_host_arm64.h
@@ -0,0 +1,202 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef ASM_KVM_HOST_ARM64_H
+#define ASM_KVM_HOST_ARM64_H
+
+#include <linux/bug.h>
+
+#include <asm/kvm_host_arm64_types.h>
+#include <asm/debug.h>
+
+#include <kvm/arm_vgic.h>
+
+#define vcpu_gp_regs(v) ((v)->arch.sae_block.gpr)
+
+#define HAVE_KVM_MMIO
+
+#include <kvm/arm64/kvm_host.h>
+#include <asm/sae.h>
+
+#define KVM_HAVE_MMU_RWLOCK
+#define KVM_MAX_VCPUS 1
+
+#define KVM_VCPU_VALID_FEATURES 0
+
+#define KVM_HALT_POLL_NS_DEFAULT 50000
+
+#define __ctxt_sys_reg(ctx, reg) NULL
+struct kvm_cpu_context {
+ /*
+ * These are just for 32 bit, which we don't have, making them RES0.
+ * They are exposed to user space.
+ * Arm KVM seemingly does not enforce RES0.
+ */
+ u64 spsr_abt;
+ u64 spsr_und;
+ u64 spsr_irq;
+ u64 spsr_fiq;
+
+ __vector128 __aligned(16) vregs[32];
+};
+
+struct kvm_vcpu_arch {
+ struct kvm_sae_block sae_block;
+ struct kvm_sae_save_area save_area;
+ struct kvm_cpu_context ctxt;
+
+ u32 host_acrs[NUM_ACRS];
+
+ /* Hypervisor Configuration Register */
+ u64 hcr_elz;
+
+ /* Configuration flags, set once and for all before the vcpu can run */
+ u8 cflags;
+
+ /* Input flags to the hypervisor code, potentially cleared after use */
+ u8 iflags;
+
+ /* State flags for kernel bookkeeping, unused by the hypervisor code */
+ u8 sflags;
+
+ /*
+ * Don't run the guest (internal implementation need).
+ *
+ * Contrary to the flags above, this is set/cleared outside of
+ * a vcpu context, and thus cannot be mixed with the flags
+ * themselves (or the flag accesses need to be made atomic).
+ */
+ bool pause;
+
+ /* vcpu power state */
+ struct kvm_mp_state mp_state;
+ /* lock for mp_state & reset_state.reset */
+ spinlock_t mp_state_lock;
+
+ /* vcpu reset state */
+ struct vcpu_reset_state reset_state;
+
+ /* GMAP */
+ struct gmap *gmap;
+ struct kvm_s390_mmu_cache *mc;
+
+ void *debugfs_state_data;
+};
+
+struct kvm_vcpu_stat {
+ struct kvm_vcpu_stat_generic generic;
+ /* ARM64 stats */
+ u64 hvc_exit_stat;
+ u64 wfe_exit_stat;
+ u64 wfi_exit_stat;
+ u64 mmio_exit_user;
+ u64 mmio_exit_kernel;
+ u64 signal_exits;
+ u64 exits;
+ /* GMAP stats */
+ u64 pfault_sync;
+};
+
+#define kvm_vcpu_get_sp_el1(__vcpu) (&((__vcpu)->arch.sae_block.sp_el1))
+#define kvm_vcpu_get_vreg(__vcpu, _off) (&(__vcpu)->arch.ctxt.vregs[_off])
+#define kvm_vcpu_get_vregs(__vcpu) (&(__vcpu)->arch.ctxt.vregs)
+#define kvm_vcpu_get_fpsr(__vcpu) (&(__vcpu)->arch.sae_block.fpsr)
+#define kvm_vcpu_get_fpcr(__vcpu) (&(__vcpu)->arch.sae_block.fpcr)
+
+#define __vcpu_flags_preempt_disable() preempt_disable()
+#define __vcpu_flags_preempt_enable() preempt_enable()
+
+#define _vcpu_get_flag(v, flagset, ...) \
+ __vcpu_get_flag(&(v)->arch.flagset, __VA_ARGS__)
+#define _vcpu_set_flag(v, flagset, ...) \
+ __vcpu_set_flag(&(v)->arch.flagset, __VA_ARGS__)
+#define _vcpu_clear_flag(v, flagset, ...) \
+ __vcpu_clear_flag(&(v)->arch.flagset, __VA_ARGS__)
+#define _vcpu_test_and_clear_flag(v, flagset, ...) \
+ __vcpu_test_and_clear_flag(&(v)->arch.flagset, __VA_ARGS__)
+
+#define kvm_has_mte(_kvm) false
+#define vcpu_has_sve(_vcpu) false
+#define vcpu_has_ptrauth(_vcpu) false
+
+struct kvm_arch_memory_slot {
+};
+
+struct kvm_arch {
+ struct gmap *gmap;
+ u64 guest_phys_size;
+
+ /* VM-wide vCPU feature set */
+ unsigned long flags;
+
+ /* Protects VM-scoped configuration data */
+ struct mutex config_lock;
+
+ debug_info_t *dbf;
+
+ DECLARE_BITMAP(vcpu_features, KVM_VCPU_MAX_FEATURES);
+
+ unsigned long mem_limit;
+};
+
+struct kvm_vm_stat {
+ struct kvm_vm_stat_generic generic;
+};
+
+#define kvm_vm_is_protected(_kvm) false
+
+#define KVM_HVA_ERR_BAD -1UL
+#define KVM_HVA_ERR_RO_BAD -2UL
+
+#define kvm_phys_size(__kvm) ((__kvm)->arch.guest_phys_size)
+static inline bool kvm_is_error_hva(unsigned long addr)
+{
+ return IS_ERR_VALUE(addr);
+}
+
+u32 get_kvm_ipa_limit(void);
+
+static inline void kvm_arch_sync_events(struct kvm *kvm) {}
+static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
+
+int kvm_handle_guest_abort(struct kvm_vcpu *vcpu);
+
+/* arm64 guests do not use async-pf. Defined because Kbuild requires it as s390 kvm turns it on. */
+#define ASYNC_PF_PER_VCPU 0
+struct kvm_arch_async_pf {
+ unsigned long pfault_token;
+};
+
+#define __unsupp_async_call(fn) WARN_ONCE(true, "async not supported on kvm-arm64 %s", fn)
+
+static inline bool kvm_arch_can_dequeue_async_page_present(struct kvm_vcpu *vcpu)
+{
+ __unsupp_async_call(__func__);
+ return false;
+};
+
+static inline void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu,
+ struct kvm_async_pf *work)
+{
+ __unsupp_async_call(__func__);
+};
+
+static inline bool kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu,
+ struct kvm_async_pf *work)
+{
+ __unsupp_async_call(__func__);
+ return false;
+};
+
+static inline void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
+ struct kvm_async_pf *work)
+{
+ __unsupp_async_call(__func__);
+};
+
+static inline void kvm_arch_async_page_present_queued(struct kvm_vcpu *vcpu)
+{
+ __unsupp_async_call(__func__);
+};
+
+#define kvm_supports_32bit_el0() false
+
+#endif /* ASM_KVM_HOST_ARM64_H */
--
2.51.0