[PATCH 5/6] mshv: Allocate vp state page for HVCALL_MAP_VP_STATE_PAGE on L1VH

[Nuno Das Neves <nunodasneves@linux.microsoft.com>]

From: Jinank Jain <jinankjain@linux.microsoft.com>

Introduce mshv_use_overlay_gpfn() to check if a page needs to be
allocated and passed to the hypervisor to map VP state pages. This is
only needed on L1VH, and only on some (newer) versions of the
hypervisor, hence the need to check vmm_capabilities.

Introduce functions hv_map/unmap_vp_state_page() to handle the
allocation and freeing.

Signed-off-by: Jinank Jain <jinankjain@linux.microsoft.com>
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
---
 drivers/hv/mshv_root.h         | 11 +++---
 drivers/hv/mshv_root_hv_call.c | 61 +++++++++++++++++++++++++---
 drivers/hv/mshv_root_main.c    | 72 +++++++++++++++++-----------------
 3 files changed, 96 insertions(+), 48 deletions(-)

diff --git a/drivers/hv/mshv_root.h b/drivers/hv/mshv_root.h
index 0cb1e2589fe1..d7c9520ef788 100644
--- a/drivers/hv/mshv_root.h
+++ b/drivers/hv/mshv_root.h
@@ -279,11 +279,12 @@ int hv_call_set_vp_state(u32 vp_index, u64 partition_id,
 			 /* Choose between pages and bytes */
 			 struct hv_vp_state_data state_data, u64 page_count,
 			 struct page **pages, u32 num_bytes, u8 *bytes);
-int hv_call_map_vp_state_page(u64 partition_id, u32 vp_index, u32 type,
-			      union hv_input_vtl input_vtl,
-			      struct page **state_page);
-int hv_call_unmap_vp_state_page(u64 partition_id, u32 vp_index, u32 type,
-				union hv_input_vtl input_vtl);
+int hv_map_vp_state_page(u64 partition_id, u32 vp_index, u32 type,
+			 union hv_input_vtl input_vtl,
+			 struct page **state_page);
+int hv_unmap_vp_state_page(u64 partition_id, u32 vp_index, u32 type,
+			   void *page_addr,
+			   union hv_input_vtl input_vtl);
 int hv_call_create_port(u64 port_partition_id, union hv_port_id port_id,
 			u64 connection_partition_id, struct hv_port_info *port_info,
 			u8 port_vtl, u8 min_connection_vtl, int node);
diff --git a/drivers/hv/mshv_root_hv_call.c b/drivers/hv/mshv_root_hv_call.c
index 7589b1ff3515..1882cc90f2f5 100644
--- a/drivers/hv/mshv_root_hv_call.c
+++ b/drivers/hv/mshv_root_hv_call.c
@@ -526,9 +526,9 @@ int hv_call_set_vp_state(u32 vp_index, u64 partition_id,
 	return ret;
 }
 
-int hv_call_map_vp_state_page(u64 partition_id, u32 vp_index, u32 type,
-			      union hv_input_vtl input_vtl,
-			      struct page **state_page)
+static int hv_call_map_vp_state_page(u64 partition_id, u32 vp_index, u32 type,
+				     union hv_input_vtl input_vtl,
+				     struct page **state_page)
 {
 	struct hv_input_map_vp_state_page *input;
 	struct hv_output_map_vp_state_page *output;
@@ -547,7 +547,14 @@ int hv_call_map_vp_state_page(u64 partition_id, u32 vp_index, u32 type,
 		input->type = type;
 		input->input_vtl = input_vtl;
 
-		status = hv_do_hypercall(HVCALL_MAP_VP_STATE_PAGE, input, output);
+		if (*state_page) {
+			input->flags.map_location_provided = 1;
+			input->requested_map_location =
+				page_to_pfn(*state_page);
+		}
+
+		status = hv_do_hypercall(HVCALL_MAP_VP_STATE_PAGE, input,
+					 output);
 
 		if (hv_result(status) != HV_STATUS_INSUFFICIENT_MEMORY) {
 			if (hv_result_success(status))
@@ -565,8 +572,39 @@ int hv_call_map_vp_state_page(u64 partition_id, u32 vp_index, u32 type,
 	return ret;
 }
 
-int hv_call_unmap_vp_state_page(u64 partition_id, u32 vp_index, u32 type,
-				union hv_input_vtl input_vtl)
+static bool mshv_use_overlay_gpfn(void)
+{
+	return hv_l1vh_partition() &&
+	       mshv_root.vmm_caps.vmm_can_provide_overlay_gpfn;
+}
+
+int hv_map_vp_state_page(u64 partition_id, u32 vp_index, u32 type,
+			 union hv_input_vtl input_vtl,
+			 struct page **state_page)
+{
+	int ret = 0;
+	struct page *allocated_page = NULL;
+
+	if (mshv_use_overlay_gpfn()) {
+		allocated_page = alloc_page(GFP_KERNEL);
+		if (!allocated_page)
+			return -ENOMEM;
+		*state_page = allocated_page;
+	} else {
+		*state_page = NULL;
+	}
+
+	ret = hv_call_map_vp_state_page(partition_id, vp_index, type, input_vtl,
+					state_page);
+
+	if (ret && allocated_page)
+		__free_page(allocated_page);
+
+	return ret;
+}
+
+static int hv_call_unmap_vp_state_page(u64 partition_id, u32 vp_index, u32 type,
+				       union hv_input_vtl input_vtl)
 {
 	unsigned long flags;
 	u64 status;
@@ -590,6 +628,17 @@ int hv_call_unmap_vp_state_page(u64 partition_id, u32 vp_index, u32 type,
 	return hv_result_to_errno(status);
 }
 
+int hv_unmap_vp_state_page(u64 partition_id, u32 vp_index, u32 type,
+			   void *page_addr, union hv_input_vtl input_vtl)
+{
+	int ret = hv_call_unmap_vp_state_page(partition_id, vp_index, type, input_vtl);
+
+	if (mshv_use_overlay_gpfn() && page_addr)
+		__free_page(virt_to_page(page_addr));
+
+	return ret;
+}
+
 int
 hv_call_get_partition_property_ex(u64 partition_id, u64 property_code, u64 arg,
 				  void *property_value, size_t property_value_sz)
diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c
index 29f61ecc9771..f91880cc9e29 100644
--- a/drivers/hv/mshv_root_main.c
+++ b/drivers/hv/mshv_root_main.c
@@ -964,28 +964,25 @@ mshv_partition_ioctl_create_vp(struct mshv_partition *partition,
 	if (ret)
 		return ret;
 
-	ret = hv_call_map_vp_state_page(partition->pt_id, args.vp_index,
-					HV_VP_STATE_PAGE_INTERCEPT_MESSAGE,
-					input_vtl_zero,
-					&intercept_message_page);
+	ret = hv_map_vp_state_page(partition->pt_id, args.vp_index,
+				   HV_VP_STATE_PAGE_INTERCEPT_MESSAGE,
+				   input_vtl_zero, &intercept_message_page);
 	if (ret)
 		goto destroy_vp;
 
 	if (!mshv_partition_encrypted(partition)) {
-		ret = hv_call_map_vp_state_page(partition->pt_id, args.vp_index,
-						HV_VP_STATE_PAGE_REGISTERS,
-						input_vtl_zero,
-						&register_page);
+		ret = hv_map_vp_state_page(partition->pt_id, args.vp_index,
+					   HV_VP_STATE_PAGE_REGISTERS,
+					   input_vtl_zero, &register_page);
 		if (ret)
 			goto unmap_intercept_message_page;
 	}
 
 	if (mshv_partition_encrypted(partition) &&
 	    is_ghcb_mapping_available()) {
-		ret = hv_call_map_vp_state_page(partition->pt_id, args.vp_index,
-						HV_VP_STATE_PAGE_GHCB,
-						input_vtl_normal,
-						&ghcb_page);
+		ret = hv_map_vp_state_page(partition->pt_id, args.vp_index,
+					   HV_VP_STATE_PAGE_GHCB,
+					   input_vtl_normal, &ghcb_page);
 		if (ret)
 			goto unmap_register_page;
 	}
@@ -1049,21 +1046,19 @@ mshv_partition_ioctl_create_vp(struct mshv_partition *partition,
 	if (hv_scheduler_type == HV_SCHEDULER_TYPE_ROOT)
 		mshv_vp_stats_unmap(partition->pt_id, args.vp_index);
 unmap_ghcb_page:
-	if (mshv_partition_encrypted(partition) && is_ghcb_mapping_available()) {
-		hv_call_unmap_vp_state_page(partition->pt_id, args.vp_index,
-					    HV_VP_STATE_PAGE_GHCB,
-					    input_vtl_normal);
-	}
+	if (mshv_partition_encrypted(partition) && is_ghcb_mapping_available())
+		hv_unmap_vp_state_page(partition->pt_id, args.vp_index,
+				       HV_VP_STATE_PAGE_GHCB, vp->vp_ghcb_page,
+				       input_vtl_normal);
 unmap_register_page:
-	if (!mshv_partition_encrypted(partition)) {
-		hv_call_unmap_vp_state_page(partition->pt_id, args.vp_index,
-					    HV_VP_STATE_PAGE_REGISTERS,
-					    input_vtl_zero);
-	}
+	if (!mshv_partition_encrypted(partition))
+		hv_unmap_vp_state_page(partition->pt_id, args.vp_index,
+				       HV_VP_STATE_PAGE_REGISTERS,
+				       vp->vp_register_page, input_vtl_zero);
 unmap_intercept_message_page:
-	hv_call_unmap_vp_state_page(partition->pt_id, args.vp_index,
-				    HV_VP_STATE_PAGE_INTERCEPT_MESSAGE,
-				    input_vtl_zero);
+	hv_unmap_vp_state_page(partition->pt_id, args.vp_index,
+			       HV_VP_STATE_PAGE_INTERCEPT_MESSAGE,
+			       vp->vp_intercept_msg_page, input_vtl_zero);
 destroy_vp:
 	hv_call_delete_vp(partition->pt_id, args.vp_index);
 	return ret;
@@ -1804,24 +1799,27 @@ static void destroy_partition(struct mshv_partition *partition)
 				mshv_vp_stats_unmap(partition->pt_id, vp->vp_index);
 
 			if (vp->vp_register_page) {
-				(void)hv_call_unmap_vp_state_page(partition->pt_id,
-								  vp->vp_index,
-								  HV_VP_STATE_PAGE_REGISTERS,
-								  input_vtl_zero);
+				(void)hv_unmap_vp_state_page(partition->pt_id,
+							     vp->vp_index,
+							     HV_VP_STATE_PAGE_REGISTERS,
+							     vp->vp_register_page,
+							     input_vtl_zero);
 				vp->vp_register_page = NULL;
 			}
 
-			(void)hv_call_unmap_vp_state_page(partition->pt_id,
-							  vp->vp_index,
-							  HV_VP_STATE_PAGE_INTERCEPT_MESSAGE,
-							  input_vtl_zero);
+			(void)hv_unmap_vp_state_page(partition->pt_id,
+						     vp->vp_index,
+						     HV_VP_STATE_PAGE_INTERCEPT_MESSAGE,
+						     vp->vp_intercept_msg_page,
+						     input_vtl_zero);
 			vp->vp_intercept_msg_page = NULL;
 
 			if (vp->vp_ghcb_page) {
-				(void)hv_call_unmap_vp_state_page(partition->pt_id,
-								  vp->vp_index,
-								  HV_VP_STATE_PAGE_GHCB,
-								  input_vtl_normal);
+				(void)hv_unmap_vp_state_page(partition->pt_id,
+							     vp->vp_index,
+							     HV_VP_STATE_PAGE_GHCB,
+							     vp->vp_ghcb_page,
+							     input_vtl_normal);
 				vp->vp_ghcb_page = NULL;
 			}
 
-- 
2.34.1