[RFC PATCH 09/12] linux-headers/kvm.h: add capability to forward hypercall

[Heyi Guo <guoheyi@huawei.com>]

To keep backward compatibility, we add new KVM capability
"KVM_CAP_FORWARD_HYPERCALL" to probe whether KVM supports forwarding
hypercall to userspace.

The capability should be enabled explicitly, for we don't want user
space application to deal with unexpected hypercall exits. We also use
an additional argument to pass exception bit mask, to request KVM to
forward all hypercalls except the classes specified in the bit mask.

Currently only PSCI can be set as exception, so that we can still keep
consistent with the original PSCI processing flow.

Signed-off-by: Heyi Guo <guoheyi@huawei.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Cornelia Huck <cohuck@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
---
 linux-headers/linux/kvm.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
index 18892d6..20e8a68 100644
--- a/linux-headers/linux/kvm.h
+++ b/linux-headers/linux/kvm.h
@@ -711,6 +711,8 @@ struct kvm_enable_cap {
 	__u8  pad[64];
 };
 
+#define KVM_CAP_FORWARD_HYPERCALL_EXCL_PSCI (1 << 0)
+
 /* for KVM_PPC_GET_PVINFO */
 
 #define KVM_PPC_PVINFO_FLAGS_EV_IDLE   (1<<0)
@@ -995,6 +997,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_ARM_SVE 170
 #define KVM_CAP_ARM_PTRAUTH_ADDRESS 171
 #define KVM_CAP_ARM_PTRAUTH_GENERIC 172
+#define KVM_CAP_FORWARD_HYPERCALL 174
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
-- 
1.8.3.1