From: Christian Borntraeger <borntraeger@xxxxxxxxxx>
[ Upstream commit 35b3fde6203b932b2b1a5b53b3d8808abc9c4f60 ]
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@xxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
[Changed capability number to 152. - Radim]
Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
---
arch/s390/include/asm/kvm_host.h | 3 ++-
arch/s390/include/uapi/asm/kvm.h | 5 ++++-
arch/s390/kvm/kvm-s390.c | 13 ++++++++++++-
arch/s390/kvm/vsie.c | 10 ++++++++++
include/uapi/linux/kvm.h | 1 +
5 files changed, 29 insertions(+), 3 deletions(-)
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index a41faf34b034..5792590d0e7c 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -181,7 +181,8 @@ struct kvm_s390_sie_block {
__u16 ipa; /* 0x0056 */
__u32 ipb; /* 0x0058 */
__u32 scaoh; /* 0x005c */
- __u8 reserved60; /* 0x0060 */
+#define FPF_BPBC 0x20
+ __u8 fpf; /* 0x0060 */
__u8 ecb; /* 0x0061 */
__u8 ecb2; /* 0x0062 */
#define ECB3_AES 0x04
diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h
index a2ffec4139ad..81c02e198527 100644
--- a/arch/s390/include/uapi/asm/kvm.h
+++ b/arch/s390/include/uapi/asm/kvm.h
@@ -197,6 +197,7 @@ struct kvm_guest_debug_arch {
#define KVM_SYNC_VRS (1UL << 6)
#define KVM_SYNC_RICCB (1UL << 7)
#define KVM_SYNC_FPRS (1UL << 8)
+#define KVM_SYNC_BPBC (1UL << 10)
/* definition of registers in kvm_run */
struct kvm_sync_regs {
__u64 prefix; /* prefix register */
@@ -217,7 +218,9 @@ struct kvm_sync_regs {
};
__u8 reserved[512]; /* for future vector expansion */
__u32 fpc; /* valid on KVM_SYNC_VRS or KVM_SYNC_FPRS */
- __u8 padding[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 */
};
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index a70ff09b4982..2032ab81b2d7 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -401,6 +401,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
case KVM_CAP_S390_RI:
r = test_facility(64);
break;
+ case KVM_CAP_S390_BPB:
+ r = test_facility(82);
+ break;
default:
r = 0;
}
@@ -1713,6 +1716,8 @@ 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;
/* fprs can be synchronized via vrs, even if the guest has no vx. With
* MACHINE_HAS_VX, (load|store)_fpu_regs() will work with vrs format.
*/
@@ -1829,7 +1834,6 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
if (test_fp_ctl(current->thread.fpu.fpc))
/* User space provided an invalid FPC, let's clear it */
current->thread.fpu.fpc = 0;
-
save_access_regs(vcpu->arch.host_acrs);
restore_access_regs(vcpu->run->s.regs.acrs);
gmap_enable(vcpu->arch.enabled_gmap);
@@ -1877,6 +1881,7 @@ 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))
@@ -2744,6 +2749,11 @@ static void sync_regs(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
if (riccb->valid)
vcpu->arch.sie_block->ecb3 |= 0x01;
}
+ 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;
+ }
kvm_run->kvm_dirty_regs = 0;
}
@@ -2762,6 +2772,7 @@ 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;
}
int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index d8673e243f13..e56b7724054c 100644
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -217,6 +217,12 @@ 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:
@@ -259,6 +265,7 @@ 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)
@@ -316,6 +323,9 @@ static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
prefix_unmapped(vsie_page);
scb_s->ecb |= scb_o->ecb & 0x10U;
}
+ /* 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 & 0x00020000U;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 4ee67cb99143..05b9bb63dbec 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -870,6 +870,7 @@ struct kvm_ppc_smmu_info {
#define KVM_CAP_S390_USER_INSTR0 130
#define KVM_CAP_MSI_DEVID 131
#define KVM_CAP_PPC_HTM 132
+#define KVM_CAP_S390_BPB 152
#ifdef KVM_CAP_IRQ_ROUTING
--
2.13.5