KVM: PPC: booke: standard PPC floating point support (8fae845f) · Commits · 戴 / test

arch/powerpc/include/asm/switch_to.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -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 *);

arch/powerpc/kvm/booke.c

+44 −0

Original line number	Diff line number	Diff line
		@@ -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:

arch/powerpc/kvm/booke.h

+31 −0

Original line number	Diff line number	Diff line
		@@ -23,6 +23,7 @@
		#include <linux/types.h>
		#include <linux/kvm_host.h>
		#include <asm/kvm_ppc.h>
		#include <asm/switch_to.h>
		#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__ */

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