KVM: s390: wire up bpb feature

BugLink: http://bugs.launchpad.net/bugs/1747090
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>
(back ported from commit 35b3fde6203b932b2b1a5b53b3d8808abc9c4f60)
Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index a409d59919344a277fac0858c2bd12ece1bd83c9..bc61c11d76844afd1c0824f94827052169dddc39 100644 (file)
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -210,7 +210,8 @@ struct kvm_s390_sie_block {
        __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

diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h
index 69d09c39bbcd00858121ebf9f6bb1f7a57ff20e1..3baf0d2df1f7e3202562b72ac0469b699676a688 100644 (file)
--- a/arch/s390/include/uapi/asm/kvm.h
+++ b/arch/s390/include/uapi/asm/kvm.h
@@ -221,6 +221,7 @@ struct kvm_guest_debug_arch {
 #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)
@@ -244,7 +245,9 @@ struct kvm_sync_regs {
        };
        __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 {

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index af09d3437631d348dca2f1a6699c34ed49c624ed..8457f676bc45b0194398472970c013b2ea7c543e 100644 (file)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -417,6 +417,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
        case KVM_CAP_S390_GS:
                r = test_facility(133);
                break;
+       case KVM_CAP_S390_BPB:
+               r = test_facility(82);
+               break;
        default:
                r = 0;
        }
@@ -2124,6 +2127,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
        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
@@ -2265,6 +2270,7 @@ static void kvm_s390_vcpu_initial_reset(struct kvm_vcpu *vcpu)
        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))
@@ -3187,6 +3193,11 @@ static void sync_regs(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
                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 */
@@ -3233,6 +3244,7 @@ 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;
+       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 */

diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index 715c19c45d9adbf565c28839d6f9d45cdb627b15..225acd515847e77d83acac3087c18b129ceba1b5 100644 (file)
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -226,6 +226,12 @@ static void unshadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
        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:
@@ -268,6 +274,7 @@ static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
        scb_s->ecb3 = 0;
        scb_s->ecd = 0;
        scb_s->fac = 0;
+       scb_s->fpf = 0;
 
        rc = prepare_cpuflags(vcpu, vsie_page);
        if (rc)
@@ -327,6 +334,9 @@ static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
                        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;

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 6cd63c18708ae1d23dbc280ed49aed55f817a2f5..7be3a85d925341cd25d1cffa60feca115a5e5ea7 100644 (file)
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -929,6 +929,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_PPC_SMT_POSSIBLE 147
 #define KVM_CAP_HYPERV_SYNIC2 148
 #define KVM_CAP_HYPERV_VP_INDEX 149
+#define KVM_CAP_S390_BPB 152
 
 #ifdef KVM_CAP_IRQ_ROUTING