[PATCH v5 03/12] KVM/x86: KVM_CAP_X86_GUEST_LBR

[Wei Wang]

Introduce KVM_CAP_X86_GUEST_LBR to allow per-VM enabling of the guest
lbr feature.

Signed-off-by: Wei Wang <wei.w.w...@intel.com>
Cc: Paolo Bonzini <pbonz...@redhat.com>
Cc: Andi Kleen <a...@linux.intel.com>
Cc: Peter Zijlstra <pet...@infradead.org>
---
 arch/x86/include/asm/kvm_host.h |  2 ++
 arch/x86/kvm/x86.c              | 15 +++++++++++++++
 include/uapi/linux/kvm.h        |  1 +
 3 files changed, 18 insertions(+)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 4660ce9..e6f6760 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -869,6 +869,7 @@ struct kvm_arch {
        atomic_t vapics_in_nmi_mode;
        struct mutex apic_map_lock;
        struct kvm_apic_map *apic_map;
+       struct x86_perf_lbr_stack lbr_stack;
 
        bool apic_access_page_done;
 
@@ -877,6 +878,7 @@ struct kvm_arch {
        bool mwait_in_guest;
        bool hlt_in_guest;
        bool pause_in_guest;
+       bool lbr_in_guest;
 
        unsigned long irq_sources_bitmap;
        s64 kvmclock_offset;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3d27206..2cdebe7 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3028,6 +3028,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long 
ext)
        case KVM_CAP_GET_MSR_FEATURES:
        case KVM_CAP_MSR_PLATFORM_INFO:
        case KVM_CAP_EXCEPTION_PAYLOAD:
+       case KVM_CAP_X86_GUEST_LBR:
                r = 1;
                break;
        case KVM_CAP_SYNC_REGS:
@@ -4562,6 +4563,20 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
                kvm->arch.exception_payload_enabled = cap->args[0];
                r = 0;
                break;
+       case KVM_CAP_X86_GUEST_LBR:
+               r = -EINVAL;
+               if (cap->args[0] &&
+                   x86_perf_get_lbr_stack(&kvm->arch.lbr_stack)) {
+                       pr_err("Failed to enable the guest lbr feature\n");
+                       break;
+               }
+               if (copy_to_user((void __user *)cap->args[1],
+                                &kvm->arch.lbr_stack,
+                                sizeof(struct x86_perf_lbr_stack)))
+                       break;
+               kvm->arch.lbr_in_guest = cap->args[0];
+               r = 0;
+               break;
        default:
                r = -EINVAL;
                break;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 6d4ea4b..a7cac96 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -988,6 +988,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_ARM_VM_IPA_SIZE 165
 #define KVM_CAP_MANUAL_DIRTY_LOG_PROTECT 166
 #define KVM_CAP_HYPERV_CPUID 167
+#define KVM_CAP_X86_GUEST_LBR 168
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
-- 
2.7.4