diff options
| author | David Woodhouse <dwmw@amazon.co.uk> | 2021-02-02 15:48:05 +0000 |
|---|---|---|
| committer | David Woodhouse <dwmw@amazon.co.uk> | 2021-02-04 14:19:38 +0000 |
| commit | 7d6bbebb7bb0294ede7bda04847272854e34f87c (patch) | |
| tree | f406d06318ceeb0e6dffa26c415f0100b69eb9c5 /arch/x86/kvm/xen.c | |
| parent | 78e9878cb376969d184a4b7fff392528fe17a3ce (diff) | |
KVM: x86/xen: Add kvm_xen_enabled static key
The code paths for Xen support are all fairly lightweight but if we hide
them behind this, they're even *more* lightweight for any system which
isn't actually hosting Xen guests.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Diffstat (limited to 'arch/x86/kvm/xen.c')
| -rw-r--r-- | arch/x86/kvm/xen.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c index b52549fc6dbc..7d03d918e595 100644 --- a/arch/x86/kvm/xen.c +++ b/arch/x86/kvm/xen.c @@ -16,6 +16,8 @@ #include "trace.h" +DEFINE_STATIC_KEY_DEFERRED_FALSE(kvm_xen_enabled, HZ); + int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data) { struct kvm *kvm = vcpu->kvm; @@ -93,10 +95,25 @@ int kvm_xen_hvm_config(struct kvm *kvm, struct kvm_xen_hvm_config *xhc) xhc->blob_size_32 || xhc->blob_size_64)) return -EINVAL; + mutex_lock(&kvm->lock); + + if (xhc->msr && !kvm->arch.xen_hvm_config.msr) + static_branch_inc(&kvm_xen_enabled.key); + else if (!xhc->msr && kvm->arch.xen_hvm_config.msr) + static_branch_slow_dec_deferred(&kvm_xen_enabled); + memcpy(&kvm->arch.xen_hvm_config, xhc, sizeof(*xhc)); + + mutex_unlock(&kvm->lock); return 0; } +void kvm_xen_destroy_vm(struct kvm *kvm) +{ + if (kvm->arch.xen_hvm_config.msr) + static_branch_slow_dec_deferred(&kvm_xen_enabled); +} + static int kvm_xen_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result) { kvm_rax_write(vcpu, result); |