On 21.12.2011, at 02:34, Scott Wood wrote:
> e500mc has a normal PPC FPU, rather than SPE which is found
> on e500v1/v2.
>
> Based on code from Liu Yu <yu....@freescale.com>.
>
> Signed-off-by: Scott Wood <scottw...@freescale.com>
> ---
> arch/powerpc/include/asm/system.h | 1 +
> arch/powerpc/kvm/booke.c | 44 +++++++++++++++++++++++++++++++++++++
> arch/powerpc/kvm/booke.h | 30 +++++++++++++++++++++++++
> 3 files changed, 75 insertions(+), 0 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/system.h
> b/arch/powerpc/include/asm/system.h
> index e30a13d..0561356 100644
> --- a/arch/powerpc/include/asm/system.h
> +++ b/arch/powerpc/include/asm/system.h
> @@ -140,6 +140,7 @@ extern void via_cuda_init(void);
> extern void read_rtc_time(void);
> extern void pmac_find_display(void);
> extern void giveup_fpu(struct task_struct *);
> +extern void load_up_fpu(void);
> extern void disable_kernel_fp(void);
> extern void enable_kernel_fp(void);
> extern void flush_fp_to_thread(struct task_struct *);
> diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
> index cf63b93..4bf43f9 100644
> --- a/arch/powerpc/kvm/booke.c
> +++ b/arch/powerpc/kvm/booke.c
> @@ -460,6 +460,11 @@ void kvmppc_core_prepare_to_enter(struct kvm_vcpu *vcpu)
> int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
> {
> int ret;
> +#ifdef CONFIG_PPC_FPU
> + unsigned int fpscr;
> + int fpexc_mode;
> + u64 fpr[32];
> +#endif
>
> if (!vcpu->arch.sane) {
> kvm_run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
> @@ -482,7 +487,46 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct
> kvm_vcpu *vcpu)
> }
>
> kvm_guest_enter();
> +
> +#ifdef CONFIG_PPC_FPU
> + /* Save userspace FPU state in stack */
> + enable_kernel_fp();
> + memcpy(fpr, current->thread.fpr, sizeof(current->thread.fpr));
> + fpscr = current->thread.fpscr.val;
> + fpexc_mode = current->thread.fpexc_mode;
> +
> + /* Restore guest FPU state to thread */
> + memcpy(current->thread.fpr, vcpu->arch.fpr, sizeof(vcpu->arch.fpr));
> + current->thread.fpscr.val = vcpu->arch.fpscr;
> +
> + /*
> + * Since we can't trap on MSR_FP in GS-mode, we consider the guest
> + * as always using the FPU. Kernel usage of FP (via
> + * enable_kernel_fp()) in this thread must not occur while
> + * vcpu->fpu_active is set.
> + */
> + vcpu->fpu_active = 1;
> +
> + kvmppc_load_guest_fp(vcpu);
> +#endif
Do you think it's possible to combine this with the book3s_pr code, so we don't
duplicate too much here?
> +
> ret = __kvmppc_vcpu_run(kvm_run, vcpu);
> +
> +#ifdef CONFIG_PPC_FPU
> + kvmppc_save_guest_fp(vcpu);
> +
> + vcpu->fpu_active = 0;
> +
> + /* Save guest FPU state from thread */
> + memcpy(vcpu->arch.fpr, current->thread.fpr, sizeof(vcpu->arch.fpr));
> + vcpu->arch.fpscr = current->thread.fpscr.val;
> +
> + /* Restore userspace FPU state from stack */
> + memcpy(current->thread.fpr, fpr, sizeof(current->thread.fpr));
> + current->thread.fpscr.val = fpscr;
> + current->thread.fpexc_mode = fpexc_mode;
> +#endif
> +
> kvm_guest_exit();
>
> out:
> diff --git a/arch/powerpc/kvm/booke.h b/arch/powerpc/kvm/booke.h
> index d53bcf2..3bf5eda 100644
> --- a/arch/powerpc/kvm/booke.h
> +++ b/arch/powerpc/kvm/booke.h
> @@ -96,4 +96,34 @@ enum int_class {
>
> void kvmppc_set_pending_interrupt(struct kvm_vcpu *vcpu, enum int_class type);
>
> +/*
> + * Load up guest vcpu FP state if it's needed.
> + * It also set the MSR_FP in thread so that host know
> + * we're holding FPU, and then host can help to save
> + * guest vcpu FP state if other threads require to use FPU.
> + * This simulates an FP unavailable fault.
> + *
> + * It requires to be called with preemption disabled.
> + */
> +static inline void kvmppc_load_guest_fp(struct kvm_vcpu *vcpu)
> +{
> +#ifdef CONFIG_PPC_FPU
> + if (vcpu->fpu_active && !(current->thread.regs->msr & MSR_FP)) {
> + load_up_fpu();
> + current->thread.regs->msr |= MSR_FP;
I'm having a hard time to grasp when shared->msr, shadow_msr and regs->msr is
used in your code :).
Alex
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