From: Christian Borntraeger <borntraeger@de.ibm.com>

Date: Wed, 17 Jan 2018 14:44:34 +0100

Subject: KVM: s390: wire up bpb feature

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Patch-mainline: v4.15-rc9

Git-commit: 35b3fde6203b932b2b1a5b53b3d8808abc9c4f60

References: bsc#1077761

The new firmware interfaces for branch prediction behaviour changes

are transparently available for the guest. Nevertheless, there is

new state attached that should be migrated and properly resetted.

Provide a mechanism for handling reset, migration and VSIE.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

Reviewed-by: David Hildenbrand <david@redhat.com>

Reviewed-by: Cornelia Huck <cohuck@redhat.com>

[Changed capability number to 152. - Radim]

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

Acked-by: Alexander Graf <agraf@suse.de>

---

 arch/s390/include/asm/kvm_host.h |    3 ++-

 arch/s390/include/uapi/asm/kvm.h |    5 ++++-

 arch/s390/kvm/kvm-s390.c         |   12 ++++++++++++

 arch/s390/kvm/vsie.c             |   10 ++++++++++

 include/uapi/linux/kvm.h         |    1 +

 5 files changed, 29 insertions(+), 2 deletions(-)

--- a/arch/s390/include/asm/kvm_host.h

+++ b/arch/s390/include/asm/kvm_host.h

@@ -210,7 +210,8 @@

 	__u16	ipa;			/* 0x0056 */

 	__u32	ipb;			/* 0x0058 */

 	__u32	scaoh;			/* 0x005c */

-	__u8	reserved60;		/* 0x0060 */

+#define FPF_BPBC 	0x20

+	__u8	fpf;			/* 0x0060 */

 #define ECB_GS		0x40

 #define ECB_TE		0x10

 #define ECB_SRSI	0x04

--- a/arch/s390/include/uapi/asm/kvm.h

+++ b/arch/s390/include/uapi/asm/kvm.h

@@ -227,6 +227,7 @@

 #define KVM_SYNC_RICCB  (1UL << 7)

 #define KVM_SYNC_FPRS   (1UL << 8)

 #define KVM_SYNC_GSCB   (1UL << 9)

+#define KVM_SYNC_BPBC   (1UL << 10)

 /* length and alignment of the sdnx as a power of two */

 #define SDNXC 8

 #define SDNXL (1UL << SDNXC)

@@ -250,7 +251,9 @@

 	};

 	__u8  reserved[512];	/* for future vector expansion */

 	__u32 fpc;		/* valid on KVM_SYNC_VRS or KVM_SYNC_FPRS */

-	__u8 padding1[52];	/* riccb needs to be 64byte aligned */

+	__u8 bpbc : 1;		/* bp mode */

+	__u8 reserved2 : 7;

+	__u8 padding1[51];	/* riccb needs to be 64byte aligned */

 	__u8 riccb[64];		/* runtime instrumentation controls block */

 	__u8 padding2[192];	/* sdnx needs to be 256byte aligned */

 	union {

--- a/arch/s390/kvm/kvm-s390.c

+++ b/arch/s390/kvm/kvm-s390.c

@@ -421,6 +421,9 @@

 	case KVM_CAP_S390_GS:

 		r = test_facility(133);

 		break;

+	case KVM_CAP_S390_BPB:

+		r = test_facility(82);

+		break;

 	default:

 		r = 0;

 	}

@@ -2198,6 +2201,8 @@

 	kvm_s390_set_prefix(vcpu, 0);

 	if (test_kvm_facility(vcpu->kvm, 64))

 		vcpu->run->kvm_valid_regs |= KVM_SYNC_RICCB;

+	if (test_kvm_facility(vcpu->kvm, 82))

+		vcpu->run->kvm_valid_regs |= KVM_SYNC_BPBC;

 	if (test_kvm_facility(vcpu->kvm, 133))

 		vcpu->run->kvm_valid_regs |= KVM_SYNC_GSCB;

 	/* fprs can be synchronized via vrs, even if the guest has no vx. With

@@ -2339,6 +2344,7 @@

 	current->thread.fpu.fpc = 0;

 	vcpu->arch.sie_block->gbea = 1;

 	vcpu->arch.sie_block->pp = 0;

+	vcpu->arch.sie_block->fpf &= ~FPF_BPBC;

 	vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;

 	kvm_clear_async_pf_completion_queue(vcpu);

 	if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm))

@@ -3298,6 +3304,11 @@

 		vcpu->arch.sie_block->ecd |= ECD_HOSTREGMGMT;

 		vcpu->arch.gs_enabled = 1;

 	}

+	if ((kvm_run->kvm_dirty_regs & KVM_SYNC_BPBC) &&

+	    test_kvm_facility(vcpu->kvm, 82)) {

+		vcpu->arch.sie_block->fpf &= ~FPF_BPBC;

+		vcpu->arch.sie_block->fpf |= kvm_run->s.regs.bpbc ? FPF_BPBC : 0;

+	}

 	save_access_regs(vcpu->arch.host_acrs);

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

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

@@ -3344,6 +3355,7 @@

 	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;

+	kvm_run->s.regs.bpbc = (vcpu->arch.sie_block->fpf & FPF_BPBC) == FPF_BPBC;

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

 	restore_access_regs(vcpu->arch.host_acrs);

 	/* Save guest register state */

--- a/arch/s390/kvm/vsie.c

+++ b/arch/s390/kvm/vsie.c

@@ -223,6 +223,12 @@

 	memcpy(scb_o->gcr, scb_s->gcr, 128);

 	scb_o->pp = scb_s->pp;

+	/* branch prediction */

+	if (test_kvm_facility(vcpu->kvm, 82)) {

+		scb_o->fpf &= ~FPF_BPBC;

+		scb_o->fpf |= scb_s->fpf & FPF_BPBC;

+	}

+

 	/* interrupt intercept */

 	switch (scb_s->icptcode) {

 	case ICPT_PROGI:

@@ -265,6 +271,7 @@

 	scb_s->ecb3 = 0;

 	scb_s->ecd = 0;

 	scb_s->fac = 0;

+	scb_s->fpf = 0;

 	rc = prepare_cpuflags(vcpu, vsie_page);

 	if (rc)

@@ -324,6 +331,9 @@

 			prefix_unmapped(vsie_page);

 		scb_s->ecb |= scb_o->ecb & ECB_TE;

 	}

+	/* branch prediction */

+	if (test_kvm_facility(vcpu->kvm, 82))

+		scb_s->fpf |= scb_o->fpf & FPF_BPBC;

 	/* SIMD */

 	if (test_kvm_facility(vcpu->kvm, 129)) {

 		scb_s->eca |= scb_o->eca & ECA_VX;

--- a/include/uapi/linux/kvm.h

+++ b/include/uapi/linux/kvm.h

@@ -932,6 +932,7 @@

 #define KVM_CAP_HYPERV_VP_INDEX 149

 #define KVM_CAP_S390_AIS_MIGRATION 150

 #define KVM_CAP_PPC_GET_CPU_CHAR 151

+#define KVM_CAP_S390_BPB 152

 #ifdef KVM_CAP_IRQ_ROUTING