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Commit bf65014d authored by Radim Krčmář's avatar Radim Krčmář
Browse files

Merge tag 'kvm-s390-next-4.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux 

KVM: s390: Changes for 4.10 (via kvm/next)

Two small optimizations to not do register reloading in
vcpu_put/get, instead do it in the ioctl path. This reduces
the overhead for schedule-intense workload that does not
exit to QEMU. (e.g. KVM guest with eventfd/irqfd that
does a lot of context switching with vhost or iothreads).
parents 8370c3d0 e1788bb9

arch/s390/kvm/interrupt.c

+1 −1
Original line number Diff line number Diff line
@@ -415,7 +415,7 @@ static int __write_machine_check(struct kvm_vcpu *vcpu, 
	int rc;



	mci.val = mchk->mcic;

	/* take care of lazy register loading via vcpu load/put */

	/* take care of lazy register loading */

	save_fpu_regs();

	save_access_regs(vcpu->run->s.regs.acrs);

arch/s390/kvm/kvm-s390.c

+26 −31
Original line number Diff line number Diff line
@@ -1812,22 +1812,7 @@ __u64 kvm_s390_get_cpu_timer(struct kvm_vcpu *vcpu) 


void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)

{

	/* Save host register state */

	save_fpu_regs();

	vcpu->arch.host_fpregs.fpc = current->thread.fpu.fpc;

	vcpu->arch.host_fpregs.regs = current->thread.fpu.regs;



	if (MACHINE_HAS_VX)

		current->thread.fpu.regs = vcpu->run->s.regs.vrs;

	else

		current->thread.fpu.regs = vcpu->run->s.regs.fprs;

	current->thread.fpu.fpc = vcpu->run->s.regs.fpc;

	if (test_fp_ctl(current->thread.fpu.fpc))

		/* User space provided an invalid FPC, let's clear it */

		current->thread.fpu.fpc = 0;



	save_access_regs(vcpu->arch.host_acrs);

	restore_access_regs(vcpu->run->s.regs.acrs);

	gmap_enable(vcpu->arch.enabled_gmap);

	atomic_or(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);

	if (vcpu->arch.cputm_enabled && !is_vcpu_idle(vcpu))
@@ -1844,16 +1829,6 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) 
	vcpu->arch.enabled_gmap = gmap_get_enabled();

	gmap_disable(vcpu->arch.enabled_gmap);



	/* Save guest register state */

	save_fpu_regs();

	vcpu->run->s.regs.fpc = current->thread.fpu.fpc;



	/* Restore host register state */

	current->thread.fpu.fpc = vcpu->arch.host_fpregs.fpc;

	current->thread.fpu.regs = vcpu->arch.host_fpregs.regs;



	save_access_regs(vcpu->run->s.regs.acrs);

	restore_access_regs(vcpu->arch.host_acrs);

}



static void kvm_s390_vcpu_initial_reset(struct kvm_vcpu *vcpu)
@@ -2243,7 +2218,6 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu, 
{

	memcpy(&vcpu->run->s.regs.acrs, &sregs->acrs, sizeof(sregs->acrs));

	memcpy(&vcpu->arch.sie_block->gcr, &sregs->crs, sizeof(sregs->crs));

	restore_access_regs(vcpu->run->s.regs.acrs);

	return 0;

}
@@ -2257,11 +2231,9 @@ int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu, 


int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)

{

	/* make sure the new values will be lazily loaded */

	save_fpu_regs();

	if (test_fp_ctl(fpu->fpc))

		return -EINVAL;

	current->thread.fpu.fpc = fpu->fpc;

	vcpu->run->s.regs.fpc = fpu->fpc;

	if (MACHINE_HAS_VX)

		convert_fp_to_vx((__vector128 *) vcpu->run->s.regs.vrs,

				 (freg_t *) fpu->fprs);
@@ -2279,7 +2251,7 @@ int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu) 
				 (__vector128 *) vcpu->run->s.regs.vrs);

	else

		memcpy(fpu->fprs, vcpu->run->s.regs.fprs, sizeof(fpu->fprs));

	fpu->fpc = current->thread.fpu.fpc;

	fpu->fpc = vcpu->run->s.regs.fpc;

	return 0;

}
@@ -2740,6 +2712,20 @@ static void sync_regs(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) 
		if (riccb->valid)

			vcpu->arch.sie_block->ecb3 |= 0x01;

	}

	save_access_regs(vcpu->arch.host_acrs);

	restore_access_regs(vcpu->run->s.regs.acrs);

	/* save host (userspace) fprs/vrs */

	save_fpu_regs();

	vcpu->arch.host_fpregs.fpc = current->thread.fpu.fpc;

	vcpu->arch.host_fpregs.regs = current->thread.fpu.regs;

	if (MACHINE_HAS_VX)

		current->thread.fpu.regs = vcpu->run->s.regs.vrs;

	else

		current->thread.fpu.regs = vcpu->run->s.regs.fprs;

	current->thread.fpu.fpc = vcpu->run->s.regs.fpc;

	if (test_fp_ctl(current->thread.fpu.fpc))

		/* User space provided an invalid FPC, let's clear it */

		current->thread.fpu.fpc = 0;



	kvm_run->kvm_dirty_regs = 0;

}
@@ -2758,6 +2744,15 @@ static void store_regs(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) 
	kvm_run->s.regs.pft = vcpu->arch.pfault_token;

	kvm_run->s.regs.pfs = vcpu->arch.pfault_select;

	kvm_run->s.regs.pfc = vcpu->arch.pfault_compare;

	save_access_regs(vcpu->run->s.regs.acrs);

	restore_access_regs(vcpu->arch.host_acrs);

	/* Save guest register state */

	save_fpu_regs();

	vcpu->run->s.regs.fpc = current->thread.fpu.fpc;

	/* Restore will be done lazily at return */

	current->thread.fpu.fpc = vcpu->arch.host_fpregs.fpc;

	current->thread.fpu.regs = vcpu->arch.host_fpregs.regs;



}



int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
@@ -2874,7 +2869,7 @@ int kvm_s390_vcpu_store_status(struct kvm_vcpu *vcpu, unsigned long addr) 
{

	/*

	 * The guest FPRS and ACRS are in the host FPRS/ACRS due to the lazy

	 * copying in vcpu load/put. Lets update our copies before we save

	 * switch in the run ioctl. Let's update our copies before we save

	 * it into the save area

	 */

	save_fpu_regs();