[RFC PATCH v1 18/34] KVM: introspection: extend KVMI_VM_SET_PAGE_ACCESS with EPT view info

[Adalbert Lazăr <alazar@xxxxxxxxxxxxxxx>]

From: Ștefan Șicleru <ssicleru@xxxxxxxxxxxxxxx>

The introspection tool uses this command to set distinct access rights
on different EPT views.

Signed-off-by: Ștefan Șicleru <ssicleru@xxxxxxxxxxxxxxx>
Signed-off-by: Adalbert Lazăr <alazar@xxxxxxxxxxxxxxx>
---
 Documentation/virt/kvm/kvmi.rst |  8 +++++---
 include/uapi/linux/kvmi.h       |  4 ++--
 virt/kvm/introspection/kvmi.c   | 10 ++++++++--
 3 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/Documentation/virt/kvm/kvmi.rst b/Documentation/virt/kvm/kvmi.rst
index f4c60aba9b53..658c9df01469 100644
--- a/Documentation/virt/kvm/kvmi.rst
+++ b/Documentation/virt/kvm/kvmi.rst
@@ -1003,8 +1003,8 @@ to control events for any other register will fail with -KVM_EINVAL::
 
 	struct kvmi_vm_set_page_access {
 		__u16 count;
-		__u16 padding1;
-		__u32 padding2;
+		__u16 view;
+		__u32 padding;
 		struct kvmi_page_access_entry entries[0];
 	};
 
@@ -1026,7 +1026,7 @@ where::
 	struct kvmi_error_code
 
 Sets the access bits (rwx) for an array of ``count`` guest physical
-addresses.
+addresses, for the selected view.
 
 The valid access bits are::
 
@@ -1048,7 +1048,9 @@ In order to 'forget' an address, all three bits ('rwx') must be set.
 
 * -KVM_EINVAL - the specified access bits combination is invalid
 * -KVM_EINVAL - the padding is not zero
+* -KVM_EINVAL - the selected EPT view is invalid
 * -KVM_EINVAL - the message size is invalid
+* -KVM_EOPNOTSUPP - an EPT view was selected but the hardware doesn't support it
 * -KVM_EAGAIN - the selected vCPU can't be introspected yet
 * -KVM_ENOMEM - there is not enough memory to add the page tracking structures
 
diff --git a/include/uapi/linux/kvmi.h b/include/uapi/linux/kvmi.h
index a72c536a2c80..505a865cd115 100644
--- a/include/uapi/linux/kvmi.h
+++ b/include/uapi/linux/kvmi.h
@@ -191,8 +191,8 @@ struct kvmi_page_access_entry {
 
 struct kvmi_vm_set_page_access {
 	__u16 count;
-	__u16 padding1;
-	__u32 padding2;
+	__u16 view;
+	__u32 padding;
 	struct kvmi_page_access_entry entries[0];
 };
 
diff --git a/virt/kvm/introspection/kvmi.c b/virt/kvm/introspection/kvmi.c
index 737fe3c7a956..44b0092e304f 100644
--- a/virt/kvm/introspection/kvmi.c
+++ b/virt/kvm/introspection/kvmi.c
@@ -1187,14 +1187,20 @@ int kvmi_cmd_set_page_access(struct kvm_introspection *kvmi,
 	const struct kvmi_page_access_entry *end = req->entries + req->count;
 	int ec = 0;
 
-	if (req->padding1 || req->padding2)
+	if (req->padding)
 		return -KVM_EINVAL;
 
 	if (msg->size < struct_size(req, entries, req->count))
 		return -KVM_EINVAL;
 
+	if (!is_valid_view(req->view))
+		return -KVM_EINVAL;
+
+	if (req->view != 0 && !kvm_eptp_switching_supported)
+		return -KVM_EOPNOTSUPP;
+
 	for (; entry < end; entry++) {
-		int r = set_page_access_entry(kvmi, 0, entry);
+		int r = set_page_access_entry(kvmi, req->view, entry);
 
 		if (r && !ec)
 			ec = r;