On 17/11/15 11:13, Steve Capper wrote: > 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). Yeah, it looks like I screwed up in the base code, and somewhat fixed it in the VHE branch... And as I'm testing the full setup, I didn't spot it, sorry. Can you please give the kvm-arm64/vhe-wsinc branch a spin and let me know if it works for you? Thanks, M. -- Jazz is not dead. It just smells funny... -- 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
