On 17/11/15 11:49, Steve Capper wrote: > On 17 November 2015 at 11:25, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: >> 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 Marc, > kvm-arm64/vhe-wsinc works well on my test system. Right. So for the record (and my karma), the actual fix is: diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index a2885f5..6241785 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -29,7 +29,7 @@ static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu) * we set FPEXC.EN to prevent traps to EL1, when setting the TFP bit. */ val = vcpu->arch.hcr_el2; - if (val & HCR_RW) { + if (!(val & HCR_RW)) { write_sysreg(1 << 30, fpexc32_el2); isb(); } @@ -118,7 +118,7 @@ static 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); + fp_enabled = !(read_sysreg(cptr_el2) & CPTR_EL2_TFP); __sysreg_save_state(guest_ctxt); __sysreg32_save_state(vcpu); I'll push out both branches again later today, with these fixes (and a couple more). Many thanks for testing this Steve. 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
