From 8fae845f4956de0becc115e926d33eff46722e94 Mon Sep 17 00:00:00 2001 From: Scott Wood Date: Tue, 20 Dec 2011 15:34:45 +0000 Subject: [PATCH] KVM: PPC: booke: standard PPC floating point support e500mc has a normal PPC FPU, rather than SPE which is found on e500v1/v2. Based on code from Liu Yu . Signed-off-by: Scott Wood Signed-off-by: Alexander Graf Signed-off-by: Avi Kivity --- arch/powerpc/include/asm/switch_to.h | 1 + arch/powerpc/kvm/booke.c | 44 ++++++++++++++++++++++++++++ arch/powerpc/kvm/booke.h | 31 ++++++++++++++++++++ 3 files changed, 76 insertions(+) diff --git a/arch/powerpc/include/asm/switch_to.h b/arch/powerpc/include/asm/switch_to.h index caf82d0a00de..1622c356ba90 100644 --- a/arch/powerpc/include/asm/switch_to.h +++ b/arch/powerpc/include/asm/switch_to.h @@ -17,6 +17,7 @@ extern struct task_struct *_switch(struct thread_struct *prev, struct thread_struct *next); 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 75dbaeb2efa3..0b77be187cf7 100644 --- a/arch/powerpc/kvm/booke.c +++ b/arch/powerpc/kvm/booke.c @@ -457,6 +457,11 @@ 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; @@ -479,7 +484,46 @@ 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 + 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 d53bcf2558f5..62c4fe55d19b 100644 --- a/arch/powerpc/kvm/booke.h +++ b/arch/powerpc/kvm/booke.h @@ -23,6 +23,7 @@ #include #include #include +#include #include "timing.h" /* interrupt priortity ordering */ @@ -96,4 +97,34 @@ 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; + } +#endif +} + +/* + * Save guest vcpu FP state into thread. + * It requires to be called with preemption disabled. + */ +static inline void kvmppc_save_guest_fp(struct kvm_vcpu *vcpu) +{ +#ifdef CONFIG_PPC_FPU + if (vcpu->fpu_active && (current->thread.regs->msr & MSR_FP)) + giveup_fpu(current); +#endif +} #endif /* __KVM_BOOKE_H__ */ -- 2.39.2