On 16 November 2015 at 13:11, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: > Implement the fpsimd save restore, keeping the lazy part in > assembler (as returning to C would be overkill). > > Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> > --- > arch/arm64/kvm/hyp/Makefile | 1 + > arch/arm64/kvm/hyp/entry.S | 32 +++++++++++++++++++++++++++++++- > arch/arm64/kvm/hyp/fpsimd.S | 33 +++++++++++++++++++++++++++++++++ > arch/arm64/kvm/hyp/hyp.h | 3 +++ > arch/arm64/kvm/hyp/switch.c | 8 ++++++++ > 5 files changed, 76 insertions(+), 1 deletion(-) > create mode 100644 arch/arm64/kvm/hyp/fpsimd.S > > diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile > index 9c11b0f..56238d0 100644 > --- a/arch/arm64/kvm/hyp/Makefile > +++ b/arch/arm64/kvm/hyp/Makefile > @@ -9,3 +9,4 @@ obj-$(CONFIG_KVM_ARM_HOST) += sysreg-sr.o > obj-$(CONFIG_KVM_ARM_HOST) += debug-sr.o > obj-$(CONFIG_KVM_ARM_HOST) += entry.o > obj-$(CONFIG_KVM_ARM_HOST) += switch.o > +obj-$(CONFIG_KVM_ARM_HOST) += fpsimd.o > diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S > index 2c4449a..7552922 100644 > --- a/arch/arm64/kvm/hyp/entry.S > +++ b/arch/arm64/kvm/hyp/entry.S > @@ -27,6 +27,7 @@ > > #define CPU_GP_REG_OFFSET(x) (CPU_GP_REGS + x) > #define CPU_XREG_OFFSET(x) CPU_GP_REG_OFFSET(CPU_USER_PT_REGS + 8*x) > +#define CPU_SYSREG_OFFSET(x) (CPU_SYSREGS + 8*x) > > .text > .pushsection .hyp.text, "ax" > @@ -152,4 +153,33 @@ ENTRY(__guest_exit) > ret > ENDPROC(__guest_exit) > > - /* Insert fault handling here */ > +ENTRY(__fpsimd_guest_restore) > + push x4, lr > + > + mrs x2, cptr_el2 > + bic x2, x2, #CPTR_EL2_TFP > + msr cptr_el2, x2 > + isb > + > + mrs x3, tpidr_el2 > + > + ldr x0, [x3, #VCPU_HOST_CONTEXT] > + kern_hyp_va x0 > + add x0, x0, #CPU_GP_REG_OFFSET(CPU_FP_REGS) > + bl __fpsimd_save_state > + > + add x2, x3, #VCPU_CONTEXT > + add x0, x2, #CPU_GP_REG_OFFSET(CPU_FP_REGS) > + bl __fpsimd_restore_state > + > + mrs x1, hcr_el2 > + tbnz x1, #HCR_RW_SHIFT, 1f > + ldr x4, [x2, #CPU_SYSREG_OFFSET(FPEXC32_EL2)] > + msr fpexc32_el2, x4 > +1: > + pop x4, lr > + pop x2, x3 > + pop x0, x1 > + > + eret > +ENDPROC(__fpsimd_guest_restore) > diff --git a/arch/arm64/kvm/hyp/fpsimd.S b/arch/arm64/kvm/hyp/fpsimd.S > new file mode 100644 > index 0000000..da3f22c > --- /dev/null > +++ b/arch/arm64/kvm/hyp/fpsimd.S > @@ -0,0 +1,33 @@ > +/* > + * Copyright (C) 2015 - ARM Ltd > + * Author: Marc Zyngier <marc.zyngier@xxxxxxx> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program. If not, see <http://www.gnu.org/licenses/>. > + */ > + > +#include <linux/linkage.h> > + > +#include <asm/fpsimdmacros.h> > + > + .text > + .pushsection .hyp.text, "ax" > + > +ENTRY(__fpsimd_save_state) > + fpsimd_save x0, 1 > + ret > +ENDPROC(__fpsimd_save_state) > + > +ENTRY(__fpsimd_restore_state) > + fpsimd_restore x0, 1 > + ret > +ENDPROC(__fpsimd_restore_state) > diff --git a/arch/arm64/kvm/hyp/hyp.h b/arch/arm64/kvm/hyp/hyp.h > index bf13238..240fb79 100644 > --- a/arch/arm64/kvm/hyp/hyp.h > +++ b/arch/arm64/kvm/hyp/hyp.h > @@ -70,6 +70,9 @@ void __debug_clear_restore_state(struct kvm_vcpu *vcpu, > struct kvm_guest_debug_arch *dbg, > struct kvm_cpu_context *ctxt); > > +void __fpsimd_save_state(struct user_fpsimd_state *fp_regs); > +void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs); > + > u64 __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context *host_ctxt); > > #endif /* __ARM64_KVM_HYP_H__ */ > diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c > index a3af81a..06d3e20 100644 > --- a/arch/arm64/kvm/hyp/switch.c > +++ b/arch/arm64/kvm/hyp/switch.c > @@ -88,6 +88,7 @@ int __hyp_text __guest_run(struct kvm_vcpu *vcpu) > { > struct kvm_cpu_context *host_ctxt; > struct kvm_cpu_context *guest_ctxt; > + bool fp_enabled; > u64 exit_code; > > vcpu = kern_hyp_va(vcpu); > @@ -117,6 +118,8 @@ int __hyp_text __guest_run(struct kvm_vcpu *vcpu) > exit_code = __guest_enter(vcpu, host_ctxt); > /* And we're baaack! */ > > + fp_enabled = !!(read_sysreg(cptr_el2) & CPTR_EL2_TFP); Should this not be a single logical not? If CPTR_EL2_TFP is set then the floating point will trap in the guest, thus floating point hasn't been used by the guest? I am chasing some issues when running kvmtool on my system with this patch set applied. The above change stops NetworkManager crashing on my host. Unfortunately I am still chasing some problems with the guest (illegal instructions). > + > __sysreg_save_state(guest_ctxt); > __sysreg32_save_state(vcpu); > __timer_save_state(vcpu); > @@ -127,6 +130,11 @@ int __hyp_text __guest_run(struct kvm_vcpu *vcpu) > > __sysreg_restore_state(host_ctxt); > > + if (fp_enabled) { > + __fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs); > + __fpsimd_restore_state(&host_ctxt->gp_regs.fp_regs); > + } > + > __debug_save_state(vcpu, &vcpu->arch.vcpu_debug_state, guest_ctxt); > __debug_clear_restore_state(vcpu, &vcpu->arch.host_debug_state, host_ctxt); > > -- > 2.1.4 > > _______________________________________________ > kvmarm mailing list > kvmarm@xxxxxxxxxxxxxxxxxxxxx > https://lists.cs.columbia.edu/mailman/listinfo/kvmarm -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
