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