Subject: [PATCH v3 03/18] KVM: arm64: pkvm: Save host FPMR in host cpu context

From: Mark Rutland <[email-masked]>
Date: Tue, 2 Jun 2026 16:11:35 +0100

Protected KVM stores most of the host's system register state in
kvm_host_data::host_ctxt, which is an instance of struct
kvm_cpu_context. As kvm_cpu_context::sys_regs[] has a slot for FPMR, we
can store the host's FPMR there.

Do so, and remove kvm_host_data::fpmr.

Signed-off-by: Mark Rutland <[email-masked]>
Reviewed-by: Vladimir Murzin <[email-masked]>
Cc: Catalin Marinas <[email-masked]>
Cc: Fuad Tabba <[email-masked]>
Cc: James Morse <[email-masked]>
Cc: Marc Zyngier <[email-masked]>
Cc: Mark Brown <[email-masked]>
Cc: Oliver Upton <[email-masked]>
Cc: Will Deacon <[email-masked]>
---
 arch/arm64/include/asm/kvm_host.h       | 3 ---
 arch/arm64/kvm/hyp/include/hyp/switch.h | 6 ++++--
 arch/arm64/kvm/hyp/nvhe/hyp-main.c      | 5 +++--
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 65eead8362e0b..42b1c4764a4bf 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -775,9 +775,6 @@ struct kvm_host_data {
 	 */
 	struct cpu_sve_state *sve_state;
 
-	/* Used by pKVM only. */
-	u64	fpmr;
-
 	/* Ownership of the FP regs */
 	enum {
 		FP_STATE_FREE,
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index 98b2976837b11..cc4d011a2b380 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -554,6 +554,8 @@ static inline void fpsimd_lazy_switch_to_host(struct kvm_vcpu *vcpu)
 
 static void kvm_hyp_save_fpsimd_host(struct kvm_vcpu *vcpu)
 {
+	struct kvm_cpu_context *hctxt = host_data_ptr(host_ctxt);
+
 	/*
 	 * Non-protected kvm relies on the host restoring its sve state.
 	 * Protected kvm restores the host's sve state as not to reveal that
@@ -562,11 +564,11 @@ static void kvm_hyp_save_fpsimd_host(struct kvm_vcpu *vcpu)
 	if (system_supports_sve()) {
 		__hyp_sve_save_host();
 	} else {
-		__fpsimd_save_state(host_data_ptr(host_ctxt.fp_regs));
+		__fpsimd_save_state(&hctxt->fp_regs);
 	}
 
 	if (kvm_has_fpmr(kern_hyp_va(vcpu->kvm)))
-		*host_data_ptr(fpmr) = read_sysreg_s(SYS_FPMR);
+		ctxt_sys_reg(hctxt, FPMR) = read_sysreg_s(SYS_FPMR);
 }

diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 06db299c37a89..db60f770060e5 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -66,6 +66,7 @@ static void fpsimd_sve_flush(void)
 
 static void fpsimd_sve_sync(struct kvm_vcpu *vcpu)
 {
+	struct kvm_cpu_context *hctxt = host_data_ptr(host_ctxt);
 	bool has_fpmr;
 
 	if (!guest_owns_fp_regs())
@@ -89,10 +90,10 @@ static void fpsimd_sve_sync(struct kvm_vcpu *vcpu)
 	if (system_supports_sve())
 		__hyp_sve_restore_host();
 	else
-		__fpsimd_restore_state(host_data_ptr(host_ctxt.fp_regs));
+		__fpsimd_restore_state(&hctxt->fp_regs);
 
 	if (has_fpmr)
-		write_sysreg_s(*host_data_ptr(fpmr), SYS_FPMR);
+		write_sysreg_s(ctxt_sys_reg(hctxt, FPMR), SYS_FPMR);
 
 	*host_data_ptr(fp_owner) = FP_STATE_HOST_OWNED;
 }
-- 
2.30.2