KVM: PPC: Book3S HV: Nested guest entry via hypercall

This adds a new hypercall, H_ENTER_NESTED, which is used by a nested
hypervisor to enter one of its nested guests.  The hypercall supplies
register values in two structs.  Those values are copied by the level 0
(L0) hypervisor (the one which is running in hypervisor mode) into the
vcpu struct of the L1 guest, and then the guest is run until an
interrupt or error occurs which needs to be reported to L1 via the
hypercall return value.

Currently this assumes that the L0 and L1 hypervisors are the same
endianness, and the structs passed as arguments are in native
endianness.  If they are of different endianness, the version number
check will fail and the hcall will be rejected.

Nested hypervisors do not support indep_threads_mode=N, so this adds
code to print a warning message if the administrator has set
indep_threads_mode=N, and treat it as Y.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 230 insertions, 0 deletions

diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
index 327826248314..5b9fd7c8d931 100644
--- a/arch/powerpc/kvm/book3s_hv_nested.c
+++ b/arch/powerpc/kvm/book3s_hv_nested.c
@@ -20,6 +20,231 @@ static struct patb_entry *pseries_partition_tb;
 
 static void kvmhv_update_ptbl_cache(struct kvm_nested_guest *gp);
 
+void kvmhv_save_hv_regs(struct kvm_vcpu *vcpu, struct hv_guest_state *hr)
+{
+	struct kvmppc_vcore *vc = vcpu->arch.vcore;
+
+	hr->pcr = vc->pcr;
+	hr->dpdes = vc->dpdes;
+	hr->hfscr = vcpu->arch.hfscr;
+	hr->tb_offset = vc->tb_offset;
+	hr->dawr0 = vcpu->arch.dawr;
+	hr->dawrx0 = vcpu->arch.dawrx;
+	hr->ciabr = vcpu->arch.ciabr;
+	hr->purr = vcpu->arch.purr;
+	hr->spurr = vcpu->arch.spurr;
+	hr->ic = vcpu->arch.ic;
+	hr->vtb = vc->vtb;
+	hr->srr0 = vcpu->arch.shregs.srr0;
+	hr->srr1 = vcpu->arch.shregs.srr1;
+	hr->sprg[0] = vcpu->arch.shregs.sprg0;
+	hr->sprg[1] = vcpu->arch.shregs.sprg1;
+	hr->sprg[2] = vcpu->arch.shregs.sprg2;
+	hr->sprg[3] = vcpu->arch.shregs.sprg3;
+	hr->pidr = vcpu->arch.pid;
+	hr->cfar = vcpu->arch.cfar;
+	hr->ppr = vcpu->arch.ppr;
+}
+
+static void save_hv_return_state(struct kvm_vcpu *vcpu, int trap,
+				 struct hv_guest_state *hr)
+{
+	struct kvmppc_vcore *vc = vcpu->arch.vcore;
+
+	hr->dpdes = vc->dpdes;
+	hr->hfscr = vcpu->arch.hfscr;
+	hr->purr = vcpu->arch.purr;
+	hr->spurr = vcpu->arch.spurr;
+	hr->ic = vcpu->arch.ic;
+	hr->vtb = vc->vtb;
+	hr->srr0 = vcpu->arch.shregs.srr0;
+	hr->srr1 = vcpu->arch.shregs.srr1;
+	hr->sprg[0] = vcpu->arch.shregs.sprg0;
+	hr->sprg[1] = vcpu->arch.shregs.sprg1;
+	hr->sprg[2] = vcpu->arch.shregs.sprg2;
+	hr->sprg[3] = vcpu->arch.shregs.sprg3;
+	hr->pidr = vcpu->arch.pid;
+	hr->cfar = vcpu->arch.cfar;
+	hr->ppr = vcpu->arch.ppr;
+	switch (trap) {
+	case BOOK3S_INTERRUPT_H_DATA_STORAGE:
+		hr->hdar = vcpu->arch.fault_dar;
+		hr->hdsisr = vcpu->arch.fault_dsisr;
+		hr->asdr = vcpu->arch.fault_gpa;
+		break;
+	case BOOK3S_INTERRUPT_H_INST_STORAGE:
+		hr->asdr = vcpu->arch.fault_gpa;
+		break;
+	case BOOK3S_INTERRUPT_H_EMUL_ASSIST:
+		hr->heir = vcpu->arch.emul_inst;
+		break;
+	}
+}
+
+static void restore_hv_regs(struct kvm_vcpu *vcpu, struct hv_guest_state *hr)
+{
+	struct kvmppc_vcore *vc = vcpu->arch.vcore;
+
+	vc->pcr = hr->pcr;
+	vc->dpdes = hr->dpdes;
+	vcpu->arch.hfscr = hr->hfscr;
+	vcpu->arch.dawr = hr->dawr0;
+	vcpu->arch.dawrx = hr->dawrx0;
+	vcpu->arch.ciabr = hr->ciabr;
+	vcpu->arch.purr = hr->purr;
+	vcpu->arch.spurr = hr->spurr;
+	vcpu->arch.ic = hr->ic;
+	vc->vtb = hr->vtb;
+	vcpu->arch.shregs.srr0 = hr->srr0;
+	vcpu->arch.shregs.srr1 = hr->srr1;
+	vcpu->arch.shregs.sprg0 = hr->sprg[0];
+	vcpu->arch.shregs.sprg1 = hr->sprg[1];
+	vcpu->arch.shregs.sprg2 = hr->sprg[2];
+	vcpu->arch.shregs.sprg3 = hr->sprg[3];
+	vcpu->arch.pid = hr->pidr;
+	vcpu->arch.cfar = hr->cfar;
+	vcpu->arch.ppr = hr->ppr;
+}
+
+void kvmhv_restore_hv_return_state(struct kvm_vcpu *vcpu,
+				   struct hv_guest_state *hr)
+{
+	struct kvmppc_vcore *vc = vcpu->arch.vcore;
+
+	vc->dpdes = hr->dpdes;
+	vcpu->arch.hfscr = hr->hfscr;
+	vcpu->arch.purr = hr->purr;
+	vcpu->arch.spurr = hr->spurr;
+	vcpu->arch.ic = hr->ic;
+	vc->vtb = hr->vtb;
+	vcpu->arch.fault_dar = hr->hdar;
+	vcpu->arch.fault_dsisr = hr->hdsisr;
+	vcpu->arch.fault_gpa = hr->asdr;
+	vcpu->arch.emul_inst = hr->heir;
+	vcpu->arch.shregs.srr0 = hr->srr0;
+	vcpu->arch.shregs.srr1 = hr->srr1;
+	vcpu->arch.shregs.sprg0 = hr->sprg[0];
+	vcpu->arch.shregs.sprg1 = hr->sprg[1];
+	vcpu->arch.shregs.sprg2 = hr->sprg[2];
+	vcpu->arch.shregs.sprg3 = hr->sprg[3];
+	vcpu->arch.pid = hr->pidr;
+	vcpu->arch.cfar = hr->cfar;
+	vcpu->arch.ppr = hr->ppr;
+}
+
+long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
+{
+	long int err, r;
+	struct kvm_nested_guest *l2;
+	struct pt_regs l2_regs, saved_l1_regs;
+	struct hv_guest_state l2_hv, saved_l1_hv;
+	struct kvmppc_vcore *vc = vcpu->arch.vcore;
+	u64 hv_ptr, regs_ptr;
+	u64 hdec_exp;
+	s64 delta_purr, delta_spurr, delta_ic, delta_vtb;
+	u64 mask;
+	unsigned long lpcr;
+
+	if (vcpu->kvm->arch.l1_ptcr == 0)
+		return H_NOT_AVAILABLE;
+
+	/* copy parameters in */
+	hv_ptr = kvmppc_get_gpr(vcpu, 4);
+	err = kvm_vcpu_read_guest(vcpu, hv_ptr, &l2_hv,
+				  sizeof(struct hv_guest_state));
+	if (err)
+		return H_PARAMETER;
+	if (l2_hv.version != HV_GUEST_STATE_VERSION)
+		return H_P2;
+
+	regs_ptr = kvmppc_get_gpr(vcpu, 5);
+	err = kvm_vcpu_read_guest(vcpu, regs_ptr, &l2_regs,
+				  sizeof(struct pt_regs));
+	if (err)
+		return H_PARAMETER;
+
+	/* translate lpid */
+	l2 = kvmhv_get_nested(vcpu->kvm, l2_hv.lpid, true);
+	if (!l2)
+		return H_PARAMETER;
+	if (!l2->l1_gr_to_hr) {
+		mutex_lock(&l2->tlb_lock);
+		kvmhv_update_ptbl_cache(l2);
+		mutex_unlock(&l2->tlb_lock);
+	}
+
+	/* save l1 values of things */
+	vcpu->arch.regs.msr = vcpu->arch.shregs.msr;
+	saved_l1_regs = vcpu->arch.regs;
+	kvmhv_save_hv_regs(vcpu, &saved_l1_hv);
+
+	/* convert TB values/offsets to host (L0) values */
+	hdec_exp = l2_hv.hdec_expiry - vc->tb_offset;
+	vc->tb_offset += l2_hv.tb_offset;
+
+	/* set L1 state to L2 state */
+	vcpu->arch.nested = l2;
+	vcpu->arch.nested_vcpu_id = l2_hv.vcpu_token;
+	vcpu->arch.regs = l2_regs;
+	vcpu->arch.shregs.msr = vcpu->arch.regs.msr;
+	mask = LPCR_DPFD | LPCR_ILE | LPCR_TC | LPCR_AIL | LPCR_LD |
+		LPCR_LPES | LPCR_MER;
+	lpcr = (vc->lpcr & ~mask) | (l2_hv.lpcr & mask);
+	restore_hv_regs(vcpu, &l2_hv);
+
+	vcpu->arch.ret = RESUME_GUEST;
+	vcpu->arch.trap = 0;
+	do {
+		if (mftb() >= hdec_exp) {
+			vcpu->arch.trap = BOOK3S_INTERRUPT_HV_DECREMENTER;
+			r = RESUME_HOST;
+			break;
+		}
+		r = kvmhv_run_single_vcpu(vcpu->arch.kvm_run, vcpu, hdec_exp,
+					  lpcr);
+	} while (is_kvmppc_resume_guest(r));
+
+	/* save L2 state for return */
+	l2_regs = vcpu->arch.regs;
+	l2_regs.msr = vcpu->arch.shregs.msr;
+	delta_purr = vcpu->arch.purr - l2_hv.purr;
+	delta_spurr = vcpu->arch.spurr - l2_hv.spurr;
+	delta_ic = vcpu->arch.ic - l2_hv.ic;
+	delta_vtb = vc->vtb - l2_hv.vtb;
+	save_hv_return_state(vcpu, vcpu->arch.trap, &l2_hv);
+
+	/* restore L1 state */
+	vcpu->arch.nested = NULL;
+	vcpu->arch.regs = saved_l1_regs;
+	vcpu->arch.shregs.msr = saved_l1_regs.msr & ~MSR_TS_MASK;
+	/* set L1 MSR TS field according to L2 transaction state */
+	if (l2_regs.msr & MSR_TS_MASK)
+		vcpu->arch.shregs.msr |= MSR_TS_S;
+	vc->tb_offset = saved_l1_hv.tb_offset;
+	restore_hv_regs(vcpu, &saved_l1_hv);
+	vcpu->arch.purr += delta_purr;
+	vcpu->arch.spurr += delta_spurr;
+	vcpu->arch.ic += delta_ic;
+	vc->vtb += delta_vtb;
+
+	kvmhv_put_nested(l2);
+
+	/* copy l2_hv_state and regs back to guest */
+	err = kvm_vcpu_write_guest(vcpu, hv_ptr, &l2_hv,
+				   sizeof(struct hv_guest_state));
+	if (err)
+		return H_AUTHORITY;
+	err = kvm_vcpu_write_guest(vcpu, regs_ptr, &l2_regs,
+				   sizeof(struct pt_regs));
+	if (err)
+		return H_AUTHORITY;
+
+	if (r == -EINTR)
+		return H_INTERRUPT;
+
+	return vcpu->arch.trap;
+}
+
 long kvmhv_nested_init(void)
 {
 	long int ptb_order;
@@ -299,3 +524,8 @@ void kvmhv_put_nested(struct kvm_nested_guest *gp)
 	if (ref == 0)
 		kvmhv_release_nested(gp);
 }
+
+long kvmhv_nested_page_fault(struct kvm_vcpu *vcpu)
+{
+	return RESUME_HOST;
+}