diff options
Diffstat (limited to 'arch/arm64/kvm')
| -rw-r--r-- | arch/arm64/kvm/fpsimd.c | 17 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/include/hyp/switch.h | 16 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/nvhe/switch.c | 2 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/vhe/switch.c | 2 |
4 files changed, 14 insertions, 23 deletions
diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c index 6012b08ecb14..edbc0183c89b 100644 --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -107,16 +107,19 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu) } /* - * Called just before entering the guest once we are no longer - * preemptable. Syncs the host's TIF_FOREIGN_FPSTATE with the KVM - * mirror of the flag used by the hypervisor. + * Called just before entering the guest once we are no longer preemptable + * and interrupts are disabled. If we have managed to run anything using + * FP while we were preemptible (such as off the back of an interrupt), + * then neither the host nor the guest own the FP hardware (and it was the + * responsibility of the code that used FP to save the existing state). + * + * Note that not supporting FP is basically the same thing as far as the + * hypervisor is concerned (nothing to save). */ void kvm_arch_vcpu_ctxflush_fp(struct kvm_vcpu *vcpu) { - if (test_thread_flag(TIF_FOREIGN_FPSTATE)) - vcpu->arch.flags |= KVM_ARM64_FP_FOREIGN_FPSTATE; - else - vcpu->arch.flags &= ~KVM_ARM64_FP_FOREIGN_FPSTATE; + if (!system_supports_fpsimd() || test_thread_flag(TIF_FOREIGN_FPSTATE)) + vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED | KVM_ARM64_FP_HOST); } /* diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index 37d9f211c200..e54320384943 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -37,21 +37,9 @@ struct kvm_exception_table_entry { extern struct kvm_exception_table_entry __start___kvm_ex_table; extern struct kvm_exception_table_entry __stop___kvm_ex_table; -/* Check whether the FP regs were dirtied while in the host-side run loop: */ -static inline bool update_fp_enabled(struct kvm_vcpu *vcpu) +/* Check whether the FP regs are owned by the guest */ +static inline bool guest_owns_fp_regs(struct kvm_vcpu *vcpu) { - /* - * When the system doesn't support FP/SIMD, we cannot rely on - * the _TIF_FOREIGN_FPSTATE flag. However, we always inject an - * abort on the very first access to FP and thus we should never - * see KVM_ARM64_FP_ENABLED. For added safety, make sure we always - * trap the accesses. - */ - if (!system_supports_fpsimd() || - vcpu->arch.flags & KVM_ARM64_FP_FOREIGN_FPSTATE) - vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED | - KVM_ARM64_FP_HOST); - return !!(vcpu->arch.flags & KVM_ARM64_FP_ENABLED); } diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c index 6db801db8f27..a6b9f1186577 100644 --- a/arch/arm64/kvm/hyp/nvhe/switch.c +++ b/arch/arm64/kvm/hyp/nvhe/switch.c @@ -43,7 +43,7 @@ static void __activate_traps(struct kvm_vcpu *vcpu) val = vcpu->arch.cptr_el2; val |= CPTR_EL2_TTA | CPTR_EL2_TAM; - if (!update_fp_enabled(vcpu)) { + if (!guest_owns_fp_regs(vcpu)) { val |= CPTR_EL2_TFP | CPTR_EL2_TZ; __activate_traps_fpsimd32(vcpu); } diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c index 969f20daf97a..46f365254e9f 100644 --- a/arch/arm64/kvm/hyp/vhe/switch.c +++ b/arch/arm64/kvm/hyp/vhe/switch.c @@ -55,7 +55,7 @@ static void __activate_traps(struct kvm_vcpu *vcpu) val |= CPTR_EL2_TAM; - if (update_fp_enabled(vcpu)) { + if (guest_owns_fp_regs(vcpu)) { if (vcpu_has_sve(vcpu)) val |= CPACR_EL1_ZEN_EL0EN | CPACR_EL1_ZEN_EL1EN; } else { |