[PATCH v1 03/13] mshv: add SEV-SNP isolated page hypercalls

[Wei Hu <weh@linux.microsoft.com>]

From: Wei Liu <wei.liu@kernel.org>

Add helpers for importing isolated pages and completing isolated
imports.  These are used by SEV-SNP guest launch flows to transfer
isolated page state to the hypervisor.

Signed-off-by: Wei Liu <wei.liu@kernel.org>
---
 drivers/hv/mshv_root.h         | 12 +++++
 drivers/hv/mshv_root_hv_call.c | 97 ++++++++++++++++++++++++++++++++++
 2 files changed, 109 insertions(+)

diff --git a/drivers/hv/mshv_root.h b/drivers/hv/mshv_root.h
index 8abb080938fd..69226179cfbf 100644
--- a/drivers/hv/mshv_root.h
+++ b/drivers/hv/mshv_root.h
@@ -379,6 +379,18 @@ void mshv_region_movable_fini(struct mshv_mem_region *region);
 bool mshv_region_movable_init(struct mshv_mem_region *region);
 
 #ifdef HV_SUPPORTS_SEV_SNP_GUESTS
+int hv_call_import_isolated_pages(u64 partition_id, u64 *pages,
+				  u64 num_pages,
+				  enum hv_isolated_page_type page_type,
+				  enum hv_isolated_page_size page_size,
+				  void (*completion_handler)(void *data,
+							     u64 *status),
+				  void *completion_data);
+int hv_call_complete_isolated_import(u64 partition_id,
+				     union hv_partition_complete_isolated_import_data *import_data,
+				     void (*completion_handler)(void *data,
+								u64 *status),
+				     void *completion_data);
 int hv_call_issue_psp_guest_request(u64 partition_id, u64 req_pfn,
 				    u64 rsp_pfn,
 				    void (*completion_handler)(void *data,
diff --git a/drivers/hv/mshv_root_hv_call.c b/drivers/hv/mshv_root_hv_call.c
index 48abe338c06f..9ddc8dd73da7 100644
--- a/drivers/hv/mshv_root_hv_call.c
+++ b/drivers/hv/mshv_root_hv_call.c
@@ -14,6 +14,10 @@
 
 #include "mshv_root.h"
 
+#define HV_ISOLATED_PAGE_BATCH_SIZE					       \
+	((HV_HYP_PAGE_SIZE - sizeof(struct hv_input_import_isolated_pages)) /  \
+	 sizeof(u64))
+
 /* Determined empirically */
 #define HV_INIT_PARTITION_DEPOSIT_PAGES 208
 #define HV_MAP_GPA_DEPOSIT_PAGES	256
@@ -1010,6 +1014,99 @@ int hv_unmap_stats_page(enum hv_stats_object_type type,
 }
 
 #ifdef HV_SUPPORTS_SEV_SNP_GUESTS
+int hv_call_import_isolated_pages(u64 partition_id, u64 *pages,
+				  u64 num_pages,
+				  enum hv_isolated_page_type page_type,
+				  enum hv_isolated_page_size page_size,
+				  void (*completion_handler)(void *data,
+							     u64 *status),
+				  void *completion_data)
+{
+	struct hv_input_import_isolated_pages *input;
+	unsigned long remaining = num_pages;
+	unsigned long flags;
+	u64 *gpa = pages;
+	u64 completed;
+	u64 status;
+	int rep_count;
+
+	if (!num_pages)
+		return -EINVAL;
+
+	if (!completion_handler) {
+		pr_err("%s: missing completion handler, page_type=%u\n",
+		       __func__, page_type);
+		return -EINVAL;
+	}
+
+	while (remaining) {
+		rep_count = min_t(unsigned long, remaining,
+				  HV_ISOLATED_PAGE_BATCH_SIZE);
+
+		local_irq_save(flags);
+		input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+		memset(input, 0, sizeof(*input));
+		input->partition_id = partition_id;
+		input->page_type = page_type;
+		input->page_size = page_size;
+		memcpy(input->page_number, gpa, rep_count * sizeof(*gpa));
+		status = hv_do_rep_hypercall(HVCALL_IMPORT_ISOLATED_PAGES,
+					     rep_count, 0, input, NULL);
+		local_irq_restore(flags);
+
+		completed = hv_repcomp(status);
+		if (hv_result(status) == HV_STATUS_CALL_PENDING)
+			completion_handler(completion_data, &status);
+
+		if (!hv_result_success(status)) {
+			pr_err("%s: completed %llu of %llu, %s\n", __func__,
+			       num_pages - remaining, num_pages,
+			       hv_result_to_string(status));
+			return hv_result_to_errno(status);
+		}
+
+		gpa += completed;
+		remaining -= completed;
+	}
+
+	return 0;
+}
+
+int hv_call_complete_isolated_import(u64 partition_id,
+				     union hv_partition_complete_isolated_import_data *import_data,
+				     void (*completion_handler)(void *data,
+								u64 *status),
+				     void *completion_data)
+{
+	struct hv_input_complete_isolated_import *input;
+	unsigned long flags;
+	u64 status;
+
+	if (!completion_handler) {
+		pr_err("%s: missing completion handler\n", __func__);
+		return -EINVAL;
+	}
+
+	local_irq_save(flags);
+	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+	memset(input, 0, sizeof(*input));
+	input->partition_id = partition_id;
+	input->import_data = *import_data;
+	status = hv_do_hypercall(HVCALL_COMPLETE_ISOLATED_IMPORT, input, NULL);
+	local_irq_restore(flags);
+
+	if (hv_result(status) == HV_STATUS_CALL_PENDING)
+		completion_handler(completion_data, &status);
+
+	if (!hv_result_success(status)) {
+		pr_err("%s: status=%s partition_id=%llu\n", __func__,
+		       hv_result_to_string(status), partition_id);
+		return hv_result_to_errno(status);
+	}
+
+	return 0;
+}
+
 int hv_call_issue_psp_guest_request(u64 partition_id, u64 req_pfn,
 				    u64 rsp_pfn,
 				    void (*completion_handler)(void *data,
-- 
2.43.0