KVM: x86: interrupt based APF 'page ready' event delivery
Concerns were expressed around APF delivery via synthetic #PF exception as
in some cases such delivery may collide with real page fault. For 'page
ready' notifications we can easily switch to using an interrupt instead.
Introduce new MSR_KVM_ASYNC_PF_INT mechanism and deprecate the legacy one.
One notable difference between the two mechanisms is that interrupt may not
get handled immediately so whenever we would like to deliver next event
(regardless of its type) we must be sure the guest had read and cleared
previous event in the slot.
While on it, get rid on 'type 1/type 2' names for APF events in the
documentation as they are causing confusion. Use 'page not present'
and 'page ready' everywhere instead.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20200525144125.143875-6-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f3897e4..2d39571 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -767,7 +767,9 @@ struct kvm_vcpu_arch {
bool halted;
gfn_t gfns[ASYNC_PF_PER_VCPU];
struct gfn_to_hva_cache data;
- u64 msr_val;
+ u64 msr_en_val; /* MSR_KVM_ASYNC_PF_EN */
+ u64 msr_int_val; /* MSR_KVM_ASYNC_PF_INT */
+ u16 vec;
u32 id;
bool send_user_only;
u32 host_apf_flags;