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. Cheers, -- Steve -- 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
