[PATCH v4 4/7] Drivers: hv: Use hv_setup_*() to set up hypercall arguments

[mhkelley58@gmail.com]

From: Michael Kelley <mhklinux@outlook.com>

Update hypercall call sites to use the new hv_setup_*() functions
to set up hypercall arguments. Since these functions zero the
fixed portion of input memory, remove now redundant zero'ing of
input fields.

In hv_post_message(), the payload area is treated as an array to
avoid wasting cycles on zero'ing it and then overwriting with
memcpy().

Signed-off-by: Michael Kelley <mhklinux@outlook.com>
---

Notes:
    Changes in v4:
    * Rename hv_hvcall_*() functions to hv_setup_*() [Easwar Hariharan]
    * Rename hv_hvcall_in_batch_size() to hv_get_input_batch_size()
      [Easwar Hariharan]
    
    Changes in v3:
    * Removed change to definition of struct hv_input_post_message so the
      'payload' remains a fixed size array. Adjust hv_post_message() so
      that the 'payload' array is not zero'ed. [Nuno Das Neves]
    * Added check of the batch size in hv_free_page_report(). [Nuno Das Neves]
    * In hv_call_deposit_pages(), use the new hv_hvcall_in_batch_size() to
      get the batch size at the start of the function, and check the
      'num_pages' input parameter against that batch size instead of against
      a separately defined constant. Also use the batch size to compute the
      size of the memory allocation. [Nuno Das Neves]

 drivers/hv/hv.c         |  4 +++-
 drivers/hv/hv_balloon.c |  8 ++++----
 drivers/hv/hv_common.c  |  9 +++------
 drivers/hv/hv_proc.c    | 23 ++++++++++-------------
 4 files changed, 20 insertions(+), 24 deletions(-)

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index b14c5f9e0ef2..ad063f535f95 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -66,7 +66,9 @@ int hv_post_message(union hv_connection_id connection_id,
 	if (hv_isolation_type_tdx() && ms_hyperv.paravisor_present)
 		aligned_msg = this_cpu_ptr(hv_context.cpu_context)->post_msg_page;
 	else
-		aligned_msg = *this_cpu_ptr(hyperv_pcpu_input_arg);
+		hv_setup_in_array(&aligned_msg,
+				   offsetof(typeof(*aligned_msg), payload),
+				   sizeof(aligned_msg->payload[0]));
 
 	aligned_msg->connectionid = connection_id;
 	aligned_msg->reserved = 0;
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index 2b4080e51f97..d9b569b204d2 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -1577,21 +1577,21 @@ static int hv_free_page_report(struct page_reporting_dev_info *pr_dev_info,
 {
 	unsigned long flags;
 	struct hv_memory_hint *hint;
-	int i, order;
+	int i, order, batch_size;
 	u64 status;
 	struct scatterlist *sg;
 
-	WARN_ON_ONCE(nents > HV_MEMORY_HINT_MAX_GPA_PAGE_RANGES);
 	WARN_ON_ONCE(sgl->length < (HV_HYP_PAGE_SIZE << page_reporting_order));
 	local_irq_save(flags);
-	hint = *this_cpu_ptr(hyperv_pcpu_input_arg);
+
+	batch_size = hv_setup_in_array(&hint, sizeof(*hint), sizeof(hint->ranges[0]));
 	if (!hint) {
 		local_irq_restore(flags);
 		return -ENOSPC;
 	}
+	WARN_ON_ONCE(nents > batch_size);
 
 	hint->heat_type = HV_EXTMEM_HEAT_HINT_COLD_DISCARD;
-	hint->reserved = 0;
 	for_each_sg(sgl, sg, nents, i) {
 		union hv_gpa_page_range *range;
 
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index 49898d10faff..ae56397af1ed 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -267,7 +267,7 @@ void __init hv_get_partition_id(void)
 	u64 status, pt_id;
 
 	local_irq_save(flags);
-	output = *this_cpu_ptr(hyperv_pcpu_input_arg);
+	hv_setup_inout(NULL, 0, &output, sizeof(*output));
 	status = hv_do_hypercall(HVCALL_GET_PARTITION_ID, NULL, output);
 	pt_id = output->partition_id;
 	local_irq_restore(flags);
@@ -288,13 +288,10 @@ u8 __init get_vtl(void)
 	u64 ret;
 
 	local_irq_save(flags);
-	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
-	output = *this_cpu_ptr(hyperv_pcpu_output_arg);
-
-	memset(input, 0, struct_size(input, names, 1));
+	hv_setup_inout_array(&input, sizeof(*input), sizeof(input->names[0]),
+			     &output, sizeof(*output), sizeof(output->values[0]));
 	input->partition_id = HV_PARTITION_ID_SELF;
 	input->vp_index = HV_VP_INDEX_SELF;
-	input->input_vtl.as_uint8 = 0;
 	input->names[0] = HV_REGISTER_VSM_VP_STATUS;
 
 	ret = hv_do_hypercall(control, input, output);
diff --git a/drivers/hv/hv_proc.c b/drivers/hv/hv_proc.c
index fbb4eb3901bb..bd63830b4141 100644
--- a/drivers/hv/hv_proc.c
+++ b/drivers/hv/hv_proc.c
@@ -9,12 +9,6 @@
 #include <linux/export.h>
 #include <asm/mshyperv.h>
 
-/*
- * See struct hv_deposit_memory. The first u64 is partition ID, the rest
- * are GPAs.
- */
-#define HV_DEPOSIT_MAX (HV_HYP_PAGE_SIZE / sizeof(u64) - 1)
-
 /* Deposits exact number of pages. Must be called with interrupts enabled.  */
 int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages)
 {
@@ -25,11 +19,13 @@ int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages)
 	int order;
 	u64 status;
 	int ret;
-	u64 base_pfn;
+	u64 base_pfn, batch_size;
 	struct hv_deposit_memory *input_page;
 	unsigned long flags;
 
-	if (num_pages > HV_DEPOSIT_MAX)
+	batch_size = hv_get_input_batch_size(sizeof(*input_page),
+			   sizeof(input_page->gpa_page_list[0]));
+	if (num_pages > batch_size)
 		return -E2BIG;
 	if (!num_pages)
 		return 0;
@@ -40,7 +36,7 @@ int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages)
 		return -ENOMEM;
 	pages = page_address(page);
 
-	counts = kcalloc(HV_DEPOSIT_MAX, sizeof(int), GFP_KERNEL);
+	counts = kcalloc(batch_size, sizeof(int), GFP_KERNEL);
 	if (!counts) {
 		free_page((unsigned long)pages);
 		return -ENOMEM;
@@ -74,7 +70,9 @@ int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages)
 
 	local_irq_save(flags);
 
-	input_page = *this_cpu_ptr(hyperv_pcpu_input_arg);
+	/* Batch size is checked at the start of function; no need to repeat */
+	hv_setup_in_array(&input_page, sizeof(*input_page),
+			   sizeof(input_page->gpa_page_list[0]));
 
 	input_page->partition_id = partition_id;
 
@@ -126,9 +124,8 @@ int hv_call_add_logical_proc(int node, u32 lp_index, u32 apic_id)
 	do {
 		local_irq_save(flags);
 
-		input = *this_cpu_ptr(hyperv_pcpu_input_arg);
 		/* We don't do anything with the output right now */
-		output = *this_cpu_ptr(hyperv_pcpu_output_arg);
+		hv_setup_inout(&input, sizeof(*input), &output, sizeof(*output));
 
 		input->lp_index = lp_index;
 		input->apic_id = apic_id;
@@ -169,7 +166,7 @@ int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags)
 	do {
 		local_irq_save(irq_flags);
 
-		input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+		hv_setup_in(&input, sizeof(*input));
 
 		input->partition_id = partition_id;
 		input->vp_index = vp_index;
-- 
2.25.1