On Wed, Dec 02, 2015 at 03:29:50PM +0000, Marc Zyngier wrote: > On 02/12/15 11:53, Christoffer Dall wrote: > > On Fri, Nov 27, 2015 at 06:50:06PM +0000, Marc Zyngier 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 | 7 +++++++ > >> arch/arm64/kvm/hyp/switch.c | 8 ++++++++ > >> arch/arm64/kvm/hyp/sysreg-sr.c | 2 +- > >> 6 files changed, 81 insertions(+), 2 deletions(-) > >> 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 > > > > nit: Add a comment along the lines of: > > // Skip restoring fpexc32 for AArch64 guests > > > >> + 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 f0427ee..18365dd 100644 > >> --- a/arch/arm64/kvm/hyp/hyp.h > >> +++ b/arch/arm64/kvm/hyp/hyp.h > >> @@ -66,6 +66,13 @@ void __debug_restore_state(struct kvm_vcpu *vcpu, > >> void __debug_cond_save_host_state(struct kvm_vcpu *vcpu); > >> void __debug_cond_restore_host_state(struct kvm_vcpu *vcpu); > >> > >> +void __fpsimd_save_state(struct user_fpsimd_state *fp_regs); > >> +void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs); > >> +static inline bool __fpsimd_enabled(void) > >> +{ > >> + return !(read_sysreg(cptr_el2) & CPTR_EL2_TFP); > >> +} > >> + > >> 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 d67ed9e..8affc19 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 = __fpsimd_enabled(); > >> + > > > > what does 'enabled' really mean here? Isn't it really > > __fpsimd_is_dirty() or __fpsimd_is_guest() or something like that (I > > suck at naming too). > > It really means "the FP regs are accessible and won't explode in your > face". It doesn't necessary means dirty (though that's the way we use it > below. > > Your call, really. > meh, it's fine the way it is. Enabled for the guest I suppose is valid enough :) -Christoffer -- 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
