Merge tag 'kvm-s390-master-4.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD

KVM: s390: Fixes and improvements for 4.16

- optimization for the exitless interrupt support that was merged
  in 4.16-rc1
- improve the branch prediction blocking for nested KVM
- replace some jump tables with switch statements to improve
  expoline performance

5 files changed, 200 insertions, 154 deletions

diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index 9c7d70715862..07c6e81163bf 100644
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -22,22 +22,6 @@
 #include "trace.h"
 #include "trace-s390.h"
 
-
-static const intercept_handler_t instruction_handlers[256] = {
-	[0x01] = kvm_s390_handle_01,
-	[0x82] = kvm_s390_handle_lpsw,
-	[0x83] = kvm_s390_handle_diag,
-	[0xaa] = kvm_s390_handle_aa,
-	[0xae] = kvm_s390_handle_sigp,
-	[0xb2] = kvm_s390_handle_b2,
-	[0xb6] = kvm_s390_handle_stctl,
-	[0xb7] = kvm_s390_handle_lctl,
-	[0xb9] = kvm_s390_handle_b9,
-	[0xe3] = kvm_s390_handle_e3,
-	[0xe5] = kvm_s390_handle_e5,
-	[0xeb] = kvm_s390_handle_eb,
-};
-
 u8 kvm_s390_get_ilen(struct kvm_vcpu *vcpu)
 {
 	struct kvm_s390_sie_block *sie_block = vcpu->arch.sie_block;
@@ -129,16 +113,39 @@ static int handle_validity(struct kvm_vcpu *vcpu)
 
 static int handle_instruction(struct kvm_vcpu *vcpu)
 {
-	intercept_handler_t handler;
-
 	vcpu->stat.exit_instruction++;
 	trace_kvm_s390_intercept_instruction(vcpu,
 					     vcpu->arch.sie_block->ipa,
 					     vcpu->arch.sie_block->ipb);
-	handler = instruction_handlers[vcpu->arch.sie_block->ipa >> 8];
-	if (handler)
-		return handler(vcpu);
-	return -EOPNOTSUPP;
+
+	switch (vcpu->arch.sie_block->ipa >> 8) {
+	case 0x01:
+		return kvm_s390_handle_01(vcpu);
+	case 0x82:
+		return kvm_s390_handle_lpsw(vcpu);
+	case 0x83:
+		return kvm_s390_handle_diag(vcpu);
+	case 0xaa:
+		return kvm_s390_handle_aa(vcpu);
+	case 0xae:
+		return kvm_s390_handle_sigp(vcpu);
+	case 0xb2:
+		return kvm_s390_handle_b2(vcpu);
+	case 0xb6:
+		return kvm_s390_handle_stctl(vcpu);
+	case 0xb7:
+		return kvm_s390_handle_lctl(vcpu);
+	case 0xb9:
+		return kvm_s390_handle_b9(vcpu);
+	case 0xe3:
+		return kvm_s390_handle_e3(vcpu);
+	case 0xe5:
+		return kvm_s390_handle_e5(vcpu);
+	case 0xeb:
+		return kvm_s390_handle_eb(vcpu);
+	default:
+		return -EOPNOTSUPP;
+	}
 }
 
 static int inject_prog_on_prog_intercept(struct kvm_vcpu *vcpu)
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index aabf46f5f883..3f2c49b1a393 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -187,12 +187,6 @@ static int cpu_timer_irq_pending(struct kvm_vcpu *vcpu)
 	return kvm_s390_get_cpu_timer(vcpu) >> 63;
 }
 
-static inline int is_ioirq(unsigned long irq_type)
-{
-	return ((irq_type >= IRQ_PEND_IO_ISC_7) &&
-		(irq_type <= IRQ_PEND_IO_ISC_0));
-}
-
 static uint64_t isc_to_isc_bits(int isc)
 {
 	return (0x80 >> isc) << 24;
@@ -236,10 +230,15 @@ static inline int kvm_s390_gisa_tac_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gis
 	return test_and_clear_bit_inv(IPM_BIT_OFFSET + gisc, (unsigned long *) gisa);
 }
 
-static inline unsigned long pending_irqs(struct kvm_vcpu *vcpu)
+static inline unsigned long pending_irqs_no_gisa(struct kvm_vcpu *vcpu)
 {
 	return vcpu->kvm->arch.float_int.pending_irqs |
-		vcpu->arch.local_int.pending_irqs |
+		vcpu->arch.local_int.pending_irqs;
+}
+
+static inline unsigned long pending_irqs(struct kvm_vcpu *vcpu)
+{
+	return pending_irqs_no_gisa(vcpu) |
 		kvm_s390_gisa_get_ipm(vcpu->kvm->arch.gisa) << IRQ_PEND_IO_ISC_7;
 }
 
@@ -337,7 +336,7 @@ static void __reset_intercept_indicators(struct kvm_vcpu *vcpu)
 
 static void set_intercept_indicators_io(struct kvm_vcpu *vcpu)
 {
-	if (!(pending_irqs(vcpu) & IRQ_PEND_IO_MASK))
+	if (!(pending_irqs_no_gisa(vcpu) & IRQ_PEND_IO_MASK))
 		return;
 	else if (psw_ioint_disabled(vcpu))
 		kvm_s390_set_cpuflags(vcpu, CPUSTAT_IO_INT);
@@ -1011,24 +1010,6 @@ out:
 	return rc;
 }
 
-typedef int (*deliver_irq_t)(struct kvm_vcpu *vcpu);
-
-static const deliver_irq_t deliver_irq_funcs[] = {
-	[IRQ_PEND_MCHK_EX]        = __deliver_machine_check,
-	[IRQ_PEND_MCHK_REP]       = __deliver_machine_check,
-	[IRQ_PEND_PROG]           = __deliver_prog,
-	[IRQ_PEND_EXT_EMERGENCY]  = __deliver_emergency_signal,
-	[IRQ_PEND_EXT_EXTERNAL]   = __deliver_external_call,
-	[IRQ_PEND_EXT_CLOCK_COMP] = __deliver_ckc,
-	[IRQ_PEND_EXT_CPU_TIMER]  = __deliver_cpu_timer,
-	[IRQ_PEND_RESTART]        = __deliver_restart,
-	[IRQ_PEND_SET_PREFIX]     = __deliver_set_prefix,
-	[IRQ_PEND_PFAULT_INIT]    = __deliver_pfault_init,
-	[IRQ_PEND_EXT_SERVICE]    = __deliver_service,
-	[IRQ_PEND_PFAULT_DONE]    = __deliver_pfault_done,
-	[IRQ_PEND_VIRTIO]         = __deliver_virtio,
-};
-
 /* Check whether an external call is pending (deliverable or not) */
 int kvm_s390_ext_call_pending(struct kvm_vcpu *vcpu)
 {
@@ -1192,7 +1173,6 @@ void kvm_s390_clear_local_irqs(struct kvm_vcpu *vcpu)
 int __must_check kvm_s390_deliver_pending_interrupts(struct kvm_vcpu *vcpu)
 {
 	struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;
-	deliver_irq_t func;
 	int rc = 0;
 	unsigned long irq_type;
 	unsigned long irqs;
@@ -1212,16 +1192,57 @@ int __must_check kvm_s390_deliver_pending_interrupts(struct kvm_vcpu *vcpu)
 	while ((irqs = deliverable_irqs(vcpu)) && !rc) {
 		/* bits are in the reverse order of interrupt priority */
 		irq_type = find_last_bit(&irqs, IRQ_PEND_COUNT);
-		if (is_ioirq(irq_type)) {
+		switch (irq_type) {
+		case IRQ_PEND_IO_ISC_0:
+		case IRQ_PEND_IO_ISC_1:
+		case IRQ_PEND_IO_ISC_2:
+		case IRQ_PEND_IO_ISC_3:
+		case IRQ_PEND_IO_ISC_4:
+		case IRQ_PEND_IO_ISC_5:
+		case IRQ_PEND_IO_ISC_6:
+		case IRQ_PEND_IO_ISC_7:
 			rc = __deliver_io(vcpu, irq_type);
-		} else {
-			func = deliver_irq_funcs[irq_type];
-			if (!func) {
-				WARN_ON_ONCE(func == NULL);
-				clear_bit(irq_type, &li->pending_irqs);
-				continue;
-			}
-			rc = func(vcpu);
+			break;
+		case IRQ_PEND_MCHK_EX:
+		case IRQ_PEND_MCHK_REP:
+			rc = __deliver_machine_check(vcpu);
+			break;
+		case IRQ_PEND_PROG:
+			rc = __deliver_prog(vcpu);
+			break;
+		case IRQ_PEND_EXT_EMERGENCY:
+			rc = __deliver_emergency_signal(vcpu);
+			break;
+		case IRQ_PEND_EXT_EXTERNAL:
+			rc = __deliver_external_call(vcpu);
+			break;
+		case IRQ_PEND_EXT_CLOCK_COMP:
+			rc = __deliver_ckc(vcpu);
+			break;
+		case IRQ_PEND_EXT_CPU_TIMER:
+			rc = __deliver_cpu_timer(vcpu);
+			break;
+		case IRQ_PEND_RESTART:
+			rc = __deliver_restart(vcpu);
+			break;
+		case IRQ_PEND_SET_PREFIX:
+			rc = __deliver_set_prefix(vcpu);
+			break;
+		case IRQ_PEND_PFAULT_INIT:
+			rc = __deliver_pfault_init(vcpu);
+			break;
+		case IRQ_PEND_EXT_SERVICE:
+			rc = __deliver_service(vcpu);
+			break;
+		case IRQ_PEND_PFAULT_DONE:
+			rc = __deliver_pfault_done(vcpu);
+			break;
+		case IRQ_PEND_VIRTIO:
+			rc = __deliver_virtio(vcpu);
+			break;
+		default:
+			WARN_ONCE(1, "Unknown pending irq type %ld", irq_type);
+			clear_bit(irq_type, &li->pending_irqs);
 		}
 	}
 
@@ -1701,7 +1722,8 @@ static void __floating_irq_kick(struct kvm *kvm, u64 type)
 		kvm_s390_set_cpuflags(dst_vcpu, CPUSTAT_STOP_INT);
 		break;
 	case KVM_S390_INT_IO_MIN...KVM_S390_INT_IO_MAX:
-		kvm_s390_set_cpuflags(dst_vcpu, CPUSTAT_IO_INT);
+		if (!(type & KVM_S390_INT_IO_AI_MASK && kvm->arch.gisa))
+			kvm_s390_set_cpuflags(dst_vcpu, CPUSTAT_IO_INT);
 		break;
 	default:
 		kvm_s390_set_cpuflags(dst_vcpu, CPUSTAT_EXT_INT);
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index bd31b37b0e6f..3c0a975c2477 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -19,8 +19,6 @@
 #include <asm/processor.h>
 #include <asm/sclp.h>
 
-typedef int (*intercept_handler_t)(struct kvm_vcpu *vcpu);
-
 /* Transactional Memory Execution related macros */
 #define IS_TE_ENABLED(vcpu)	((vcpu->arch.sie_block->ecb & ECB_TE))
 #define TDB_FORMAT1		1
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index c4c4e157c036..a74578cdd3f3 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -795,55 +795,60 @@ out:
 	return rc;
 }
 
-static const intercept_handler_t b2_handlers[256] = {
-	[0x02] = handle_stidp,
-	[0x04] = handle_set_clock,
-	[0x10] = handle_set_prefix,
-	[0x11] = handle_store_prefix,
-	[0x12] = handle_store_cpu_address,
-	[0x14] = kvm_s390_handle_vsie,
-	[0x21] = handle_ipte_interlock,
-	[0x29] = handle_iske,
-	[0x2a] = handle_rrbe,
-	[0x2b] = handle_sske,
-	[0x2c] = handle_test_block,
-	[0x30] = handle_io_inst,
-	[0x31] = handle_io_inst,
-	[0x32] = handle_io_inst,
-	[0x33] = handle_io_inst,
-	[0x34] = handle_io_inst,
-	[0x35] = handle_io_inst,
-	[0x36] = handle_io_inst,
-	[0x37] = handle_io_inst,
-	[0x38] = handle_io_inst,
-	[0x39] = handle_io_inst,
-	[0x3a] = handle_io_inst,
-	[0x3b] = handle_io_inst,
-	[0x3c] = handle_io_inst,
-	[0x50] = handle_ipte_interlock,
-	[0x56] = handle_sthyi,
-	[0x5f] = handle_io_inst,
-	[0x74] = handle_io_inst,
-	[0x76] = handle_io_inst,
-	[0x7d] = handle_stsi,
-	[0xb1] = handle_stfl,
-	[0xb2] = handle_lpswe,
-};
-
 int kvm_s390_handle_b2(struct kvm_vcpu *vcpu)
 {
-	intercept_handler_t handler;
-
-	/*
-	 * A lot of B2 instructions are priviledged. Here we check for
-	 * the privileged ones, that we can handle in the kernel.
-	 * Anything else goes to userspace.
-	 */
-	handler = b2_handlers[vcpu->arch.sie_block->ipa & 0x00ff];
-	if (handler)
-		return handler(vcpu);
-
-	return -EOPNOTSUPP;
+	switch (vcpu->arch.sie_block->ipa & 0x00ff) {
+	case 0x02:
+		return handle_stidp(vcpu);
+	case 0x04:
+		return handle_set_clock(vcpu);
+	case 0x10:
+		return handle_set_prefix(vcpu);
+	case 0x11:
+		return handle_store_prefix(vcpu);
+	case 0x12:
+		return handle_store_cpu_address(vcpu);
+	case 0x14:
+		return kvm_s390_handle_vsie(vcpu);
+	case 0x21:
+	case 0x50:
+		return handle_ipte_interlock(vcpu);
+	case 0x29:
+		return handle_iske(vcpu);
+	case 0x2a:
+		return handle_rrbe(vcpu);
+	case 0x2b:
+		return handle_sske(vcpu);
+	case 0x2c:
+		return handle_test_block(vcpu);
+	case 0x30:
+	case 0x31:
+	case 0x32:
+	case 0x33:
+	case 0x34:
+	case 0x35:
+	case 0x36:
+	case 0x37:
+	case 0x38:
+	case 0x39:
+	case 0x3a:
+	case 0x3b:
+	case 0x3c:
+	case 0x5f:
+	case 0x74:
+	case 0x76:
+		return handle_io_inst(vcpu);
+	case 0x56:
+		return handle_sthyi(vcpu);
+	case 0x7d:
+		return handle_stsi(vcpu);
+	case 0xb1:
+		return handle_stfl(vcpu);
+	case 0xb2:
+		return handle_lpswe(vcpu);
+	default:
+		return -EOPNOTSUPP;
+	}
 }
 
 static int handle_epsw(struct kvm_vcpu *vcpu)
@@ -1105,25 +1110,22 @@ static int handle_essa(struct kvm_vcpu *vcpu)
 	return 0;
 }
 
-static const intercept_handler_t b9_handlers[256] = {
-	[0x8a] = handle_ipte_interlock,
-	[0x8d] = handle_epsw,
-	[0x8e] = handle_ipte_interlock,
-	[0x8f] = handle_ipte_interlock,
-	[0xab] = handle_essa,
-	[0xaf] = handle_pfmf,
-};
-
 int kvm_s390_handle_b9(struct kvm_vcpu *vcpu)
 {
-	intercept_handler_t handler;
-
-	/* This is handled just as for the B2 instructions. */
-	handler = b9_handlers[vcpu->arch.sie_block->ipa & 0x00ff];
-	if (handler)
-		return handler(vcpu);
-
-	return -EOPNOTSUPP;
+	switch (vcpu->arch.sie_block->ipa & 0x00ff) {
+	case 0x8a:
+	case 0x8e:
+	case 0x8f:
+		return handle_ipte_interlock(vcpu);
+	case 0x8d:
+		return handle_epsw(vcpu);
+	case 0xab:
+		return handle_essa(vcpu);
+	case 0xaf:
+		return handle_pfmf(vcpu);
+	default:
+		return -EOPNOTSUPP;
+	}
 }
 
 int kvm_s390_handle_lctl(struct kvm_vcpu *vcpu)
@@ -1271,22 +1273,20 @@ static int handle_stctg(struct kvm_vcpu *vcpu)
 	return rc ? kvm_s390_inject_prog_cond(vcpu, rc) : 0;
 }
 
-static const intercept_handler_t eb_handlers[256] = {
-	[0x2f] = handle_lctlg,
-	[0x25] = handle_stctg,
-	[0x60] = handle_ri,
-	[0x61] = handle_ri,
-	[0x62] = handle_ri,
-};
-
 int kvm_s390_handle_eb(struct kvm_vcpu *vcpu)
 {
-	intercept_handler_t handler;
-
-	handler = eb_handlers[vcpu->arch.sie_block->ipb & 0xff];
-	if (handler)
-		return handler(vcpu);
-	return -EOPNOTSUPP;
+	switch (vcpu->arch.sie_block->ipb & 0x000000ff) {
+	case 0x25:
+		return handle_stctg(vcpu);
+	case 0x2f:
+		return handle_lctlg(vcpu);
+	case 0x60:
+	case 0x61:
+	case 0x62:
+		return handle_ri(vcpu);
+	default:
+		return -EOPNOTSUPP;
+	}
 }
 
 static int handle_tprot(struct kvm_vcpu *vcpu)
@@ -1346,10 +1346,12 @@ out_unlock:
 
 int kvm_s390_handle_e5(struct kvm_vcpu *vcpu)
 {
-	/* For e5xx... instructions we only handle TPROT */
-	if ((vcpu->arch.sie_block->ipa & 0x00ff) == 0x01)
+	switch (vcpu->arch.sie_block->ipa & 0x00ff) {
+	case 0x01:
 		return handle_tprot(vcpu);
-	return -EOPNOTSUPP;
+	default:
+		return -EOPNOTSUPP;
+	}
 }
 
 static int handle_sckpf(struct kvm_vcpu *vcpu)
@@ -1380,17 +1382,14 @@ static int handle_ptff(struct kvm_vcpu *vcpu)
 	return 0;
 }
 
-static const intercept_handler_t x01_handlers[256] = {
-	[0x04] = handle_ptff,
-	[0x07] = handle_sckpf,
-};
-
 int kvm_s390_handle_01(struct kvm_vcpu *vcpu)
 {
-	intercept_handler_t handler;
-
-	handler = x01_handlers[vcpu->arch.sie_block->ipa & 0x00ff];
-	if (handler)
-		return handler(vcpu);
-	return -EOPNOTSUPP;
+	switch (vcpu->arch.sie_block->ipa & 0x00ff) {
+	case 0x04:
+		return handle_ptff(vcpu);
+	case 0x07:
+		return handle_sckpf(vcpu);
+	default:
+		return -EOPNOTSUPP;
+	}
 }
diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index ec772700ff96..8961e3970901 100644
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -821,6 +821,7 @@ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 {
 	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
 	struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
+	int guest_bp_isolation;
 	int rc;
 
 	handle_last_fault(vcpu, vsie_page);
@@ -831,6 +832,20 @@ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 		s390_handle_mcck();
 
 	srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
+
+	/* save current guest state of bp isolation override */
+	guest_bp_isolation = test_thread_flag(TIF_ISOLATE_BP_GUEST);
+
+	/*
+	 * The guest is running with BPBC, so we have to force it on for our
+	 * nested guest. This is done by enabling BPBC globally, so the BPBC
+	 * control in the SCB (which the nested guest can modify) is simply
+	 * ignored.
+	 */
+	if (test_kvm_facility(vcpu->kvm, 82) &&
+	    vcpu->arch.sie_block->fpf & FPF_BPBC)
+		set_thread_flag(TIF_ISOLATE_BP_GUEST);
+
 	local_irq_disable();
 	guest_enter_irqoff();
 	local_irq_enable();
@@ -840,6 +855,11 @@ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 	local_irq_disable();
 	guest_exit_irqoff();
 	local_irq_enable();
+
+	/* restore guest state for bp isolation override */
+	if (!guest_bp_isolation)
+		clear_thread_flag(TIF_ISOLATE_BP_GUEST);
+
 	vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
 
 	if (rc == -EINTR) {