From: Mark Rutland Date: Thu, 19 Jun 2025 13:48:17 +0000 (+0100) Subject: KVM: arm64: Remove kvm_arch_vcpu_run_map_fp() X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=42ce432522a17685f5a84529de49e555477c0a1f;p=linux-2.6-block.git KVM: arm64: Remove kvm_arch_vcpu_run_map_fp() Historically KVM hyp code saved the host's FPSIMD state into the hosts's fpsimd_state memory, and so it was necessary to map this into the hyp Stage-1 mappings before running a vCPU. This is no longer necessary as of commits: * fbc7e61195e2 ("KVM: arm64: Unconditionally save+flush host FPSIMD/SVE/SME state") * 8eca7f6d5100 ("KVM: arm64: Remove host FPSIMD saving for non-protected KVM") Since those commits, we eagerly save the host's FPSIMD state before calling into hyp to run a vCPU, and hyp code never reads nor writes the host's fpsimd_state memory. There's no longer any need to map the host's fpsimd_state memory into the hyp Stage-1, and kvm_arch_vcpu_run_map_fp() is unnecessary but benign. Remove kvm_arch_vcpu_run_map_fp(). Currently there is no code to perform a corresponding unmap, and we never mapped the host's SVE or SME state into the hyp Stage-1, so no other code needs to be removed. Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: Fuad Tabba Cc: Marc Zyngier Cc: Mark Brown Cc: Oliver Upton Cc: Will Deacon Cc: kvmarm@lists.linux.dev Reviewed-by: Mark Brown Tested-by: Fuad Tabba Reviewed-by: Fuad Tabba Link: https://lore.kernel.org/r/20250619134817.4075340-1-mark.rutland@arm.com Signed-off-by: Marc Zyngier --- diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index d27079968341..3e41a880b062 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -1480,7 +1480,6 @@ int kvm_vm_ioctl_get_reg_writable_masks(struct kvm *kvm, struct reg_mask_range *range); /* Guest/host FPSIMD coordination helpers */ -int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu); void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu); void kvm_arch_vcpu_ctxflush_fp(struct kvm_vcpu *vcpu); void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu); diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index b223d21c063c..23dd3f3fc3eb 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -825,10 +825,6 @@ int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu) if (!kvm_arm_vcpu_is_finalized(vcpu)) return -EPERM; - ret = kvm_arch_vcpu_run_map_fp(vcpu); - if (ret) - return ret; - if (likely(vcpu_has_run_once(vcpu))) return 0; diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c index 8f6c8f57c6b9..15e17aca1dec 100644 --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -14,32 +14,6 @@ #include #include -/* - * Called on entry to KVM_RUN unless this vcpu previously ran at least - * once and the most recent prior KVM_RUN for this vcpu was called from - * the same task as current (highly likely). - * - * This is guaranteed to execute before kvm_arch_vcpu_load_fp(vcpu), - * such that on entering hyp the relevant parts of current are already - * mapped. - */ -int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu) -{ - struct user_fpsimd_state *fpsimd = ¤t->thread.uw.fpsimd_state; - int ret; - - /* pKVM has its own tracking of the host fpsimd state. */ - if (is_protected_kvm_enabled()) - return 0; - - /* Make sure the host task fpsimd state is visible to hyp: */ - ret = kvm_share_hyp(fpsimd, fpsimd + 1); - if (ret) - return ret; - - return 0; -} - /* * Prepare vcpu for saving the host's FPSIMD state and loading the guest's. * The actual loading is done by the FPSIMD access trap taken to hyp.