[PATCH v5 24/31] KVM: s390: arm64: Introduce host definitions
Steffen Eiden
seiden at linux.ibm.com
Fri Jul 31 06:08:52 PDT 2026
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), and various defines required
to run arm64 guests.
Enlighten asm/kvm_host.h for the new header variant. The new
header is chosen instead of asm/kvm_host_s390.h if KVM_S390_ARM64
is defined.
Co-developed-by: Andreas Grapentin <gra at linux.ibm.com>
Signed-off-by: Andreas Grapentin <gra at linux.ibm.com>
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/s390/include/asm/kvm.h | 6 +
arch/s390/include/asm/kvm_host.h | 9 +
arch/s390/include/asm/kvm_host_arm64.h | 224 +++++++++++++++++++++++++
arch/s390/kernel/entry.S | 3 -
4 files changed, 239 insertions(+), 3 deletions(-)
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..aeb11dc631d5
--- /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/arm64/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 147325978225..cd6d572883ab 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_OPERATION 0x01
#define PGM_PRIVILEGED_OP 0x02
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..956ae6636597
--- /dev/null
+++ b/arch/s390/include/asm/kvm_host_arm64.h
@@ -0,0 +1,224 @@
+/* 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_types.h>
+#include <asm/debug.h>
+
+#define vcpu_gp_regs(v) ((v)->arch.sae_block.gpr)
+
+#include <arm64/kvm_host.h>
+#include <arm64/ptrace.h>
+
+#include <asm/sae.h>
+
+#define KVM_HAVE_MMU_RWLOCK
+#define KVM_MAX_VCPUS 1
+#define KVM_S390_ARM64_IMPL_FEATURES \
+ (BIT(KVM_ARM_VCPU_PTRAUTH_ADDRESS) | BIT(KVM_ARM_VCPU_PTRAUTH_GENERIC))
+
+#define KVM_HALT_POLL_NS_DEFAULT 50000
+
+/* Minimal (=no) vgic definitions */
+#define KVM_IRQCHIP_NUM_PINS 1
+#define irqchip_in_kernel(_k) false
+
+#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.
+ */
+ 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_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;
+};
+
+static inline bool __vcpu_has_feature(const struct kvm_arch *ka, int feature)
+{
+ return test_bit(feature, ka->vcpu_features);
+}
+
+struct kvm_vm_stat {
+ struct kvm_vm_stat_generic generic;
+};
+
+static inline bool system_has_full_ptr_auth(void)
+{
+ return true;
+}
+
+#define kvm_vm_is_protected(_kvm) false
+#define vcpu_is_protected(_vcpu) false
+
+#define vcpu_is_loaded(_vcpu) ((_vcpu)->cpu != -1)
+
+#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);
+
+/* unused, but required functions */
+static inline void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot) {}
+static inline void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen) {}
+static inline void kvm_arch_flush_shadow_all(struct kvm *kvm) {}
+static inline void kvm_arch_flush_shadow_memslot(struct kvm *kvm, struct kvm_memory_slot *slot) {}
+static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {}
+static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {}
+static inline void kvm_arch_sync_events(struct kvm *kvm) {}
+static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
+static inline void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
+ struct kvm_memory_slot *slot,
+ gfn_t gfn_offset,
+ unsigned long mask) {}
+
+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 */
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 248bea26921b..4e5b499b3540 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -253,9 +253,6 @@ SYM_FUNC_START(__sae64a)
stmg %r6,%r14,__SF_GPRS(%r15) # store kernel registers
STBEAR __SF_SAE_BEAR(%r15) # save breaking event address register
.insn rre,0xb9a50000,%r2,0 # Start Arm Execution
-# Let the next instruction be NOP to avoid triggering a machine check
-# and handling it in a guest as result of the instruction execution.
- nopr 7
LBEAR __SF_SAE_BEAR(%r15) # restore breaking event address register
lmg %r6,%r14,__SF_GPRS(%r15) # restore kernel registers
xgr %r0,%r0 # clear guest registers to
--
2.53.0
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