KVM: PPC: Introduce shared page
For transparent variable sharing between the hypervisor and guest, I introduce
a shared page. This shared page will contain all the registers the guest can
read and write safely without exiting guest context.
This patch only implements the stubs required for the basic structure of the
shared page. The actual register moving follows.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
index a3cef30..b3385dd 100644
--- a/arch/powerpc/kvm/book3s.c
+++ b/arch/powerpc/kvm/book3s.c
@@ -1242,6 +1242,10 @@
if (err)
goto free_shadow_vcpu;
+ vcpu->arch.shared = (void*)__get_free_page(GFP_KERNEL|__GFP_ZERO);
+ if (!vcpu->arch.shared)
+ goto uninit_vcpu;
+
vcpu->arch.host_retip = kvm_return_point;
vcpu->arch.host_msr = mfmsr();
#ifdef CONFIG_PPC_BOOK3S_64
@@ -1268,10 +1272,12 @@
err = kvmppc_mmu_init(vcpu);
if (err < 0)
- goto free_shadow_vcpu;
+ goto uninit_vcpu;
return vcpu;
+uninit_vcpu:
+ kvm_vcpu_uninit(vcpu);
free_shadow_vcpu:
kfree(vcpu_book3s->shadow_vcpu);
free_vcpu:
@@ -1284,6 +1290,7 @@
{
struct kvmppc_vcpu_book3s *vcpu_book3s = to_book3s(vcpu);
+ free_page((unsigned long)vcpu->arch.shared);
kvm_vcpu_uninit(vcpu);
kfree(vcpu_book3s->shadow_vcpu);
vfree(vcpu_book3s);