[PATCH v4 3/7] x86/hyperv: Use hv_setup_*() to set up hypercall arguments -- part 2

[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 calls to memset()
and explicit zero'ing of input fields.

For hv_mark_gpa_visibility(), use the computed batch_size instead
of HV_MAX_MODIFY_GPA_REP_COUNT. Also update the associated gpa_page_list[]
field to have zero size, which is more consistent with other array
arguments to hypercalls. Due to the interaction with the calling
hv_vtom_set_host_visibility(), HV_MAX_MODIFY_GPA_REP_COUNT cannot be
completely eliminated without some further restructuring, but that's
for another patch set.

Similarly, for the nested flush functions, update the gpa_list[] to
have zero size. Again, separate restructuring would be required to
completely eliminate the need for HV_MAX_FLUSH_REP_COUNT.

Finally, hyperv_flush_tlb_others_ex() requires special handling
because the input consists of two arrays -- one for the hv_vp_set and
another for the gva list. The batch_size computed by hv_setup_in_array()
is adjusted to account for the number of entries in the hv_vp_set.

Signed-off-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Nuno Das Neves <nunodasneves@linux.microsoft.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 v2:
    * In hyperv_flush_tlb_others_ex(), added check of the adjusted
      max_gvas to make sure it doesn't go to zero or negative, which would
      happen if there is insufficient space to hold the hv_vpset and have
      at least one entry in the gva list. Since an hv_vpset currently
      represents a maximum of 4096 CPUs, the hv_vpset size does not exceed
      512 bytes and there should always be sufficent space. But do the
      check just in case something changes. [Nuno Das Neves]

 arch/x86/hyperv/ivm.c       | 18 +++++++++---------
 arch/x86/hyperv/mmu.c       | 19 +++++--------------
 arch/x86/hyperv/nested.c    | 14 +++++---------
 include/hyperv/hvgdk_mini.h |  4 ++--
 4 files changed, 21 insertions(+), 34 deletions(-)

diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index ade6c665c97e..3084ae8a3eed 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -474,30 +474,30 @@ static int hv_mark_gpa_visibility(u16 count, const u64 pfn[],
 {
 	struct hv_gpa_range_for_visibility *input;
 	u64 hv_status;
+	int batch_size;
 	unsigned long flags;
 
 	/* no-op if partition isolation is not enabled */
 	if (!hv_is_isolation_supported())
 		return 0;
 
-	if (count > HV_MAX_MODIFY_GPA_REP_COUNT) {
-		pr_err("Hyper-V: GPA count:%d exceeds supported:%lu\n", count,
-			HV_MAX_MODIFY_GPA_REP_COUNT);
+	local_irq_save(flags);
+	batch_size = hv_setup_in_array(&input, sizeof(*input),
+					sizeof(input->gpa_page_list[0]));
+	if (unlikely(!input)) {
+		local_irq_restore(flags);
 		return -EINVAL;
 	}
 
-	local_irq_save(flags);
-	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
-
-	if (unlikely(!input)) {
+	if (count > batch_size) {
+		pr_err("Hyper-V: GPA count:%d exceeds supported:%u\n", count,
+		       batch_size);
 		local_irq_restore(flags);
 		return -EINVAL;
 	}
 
 	input->partition_id = HV_PARTITION_ID_SELF;
 	input->host_visibility = visibility;
-	input->reserved0 = 0;
-	input->reserved1 = 0;
 	memcpy((void *)input->gpa_page_list, pfn, count * sizeof(*pfn));
 	hv_status = hv_do_rep_hypercall(
 			HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY, count,
diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c
index cfcb60468b01..f1aeb5bdb29a 100644
--- a/arch/x86/hyperv/mmu.c
+++ b/arch/x86/hyperv/mmu.c
@@ -72,7 +72,7 @@ static void hyperv_flush_tlb_multi(const struct cpumask *cpus,
 
 	local_irq_save(flags);
 
-	flush = *this_cpu_ptr(hyperv_pcpu_input_arg);
+	max_gvas = hv_setup_in_array(&flush, sizeof(*flush), sizeof(flush->gva_list[0]));
 
 	if (unlikely(!flush)) {
 		local_irq_restore(flags);
@@ -86,13 +86,10 @@ static void hyperv_flush_tlb_multi(const struct cpumask *cpus,
 		 */
 		flush->address_space = virt_to_phys(info->mm->pgd);
 		flush->address_space &= CR3_ADDR_MASK;
-		flush->flags = 0;
 	} else {
-		flush->address_space = 0;
 		flush->flags = HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES;
 	}
 
-	flush->processor_mask = 0;
 	if (cpumask_equal(cpus, cpu_present_mask)) {
 		flush->flags |= HV_FLUSH_ALL_PROCESSORS;
 	} else {
@@ -139,8 +136,6 @@ static void hyperv_flush_tlb_multi(const struct cpumask *cpus,
 	 * We can flush not more than max_gvas with one hypercall. Flush the
 	 * whole address space if we were asked to do more.
 	 */
-	max_gvas = (PAGE_SIZE - sizeof(*flush)) / sizeof(flush->gva_list[0]);
-
 	if (info->end == TLB_FLUSH_ALL) {
 		flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
 		status = hv_do_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE,
@@ -179,7 +174,7 @@ static u64 hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
 	if (!(ms_hyperv.hints & HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
 		return HV_STATUS_INVALID_PARAMETER;
 
-	flush = *this_cpu_ptr(hyperv_pcpu_input_arg);
+	max_gvas = hv_setup_in_array(&flush, sizeof(*flush), sizeof(flush->gva_list[0]));
 
 	if (info->mm) {
 		/*
@@ -188,14 +183,10 @@ static u64 hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
 		 */
 		flush->address_space = virt_to_phys(info->mm->pgd);
 		flush->address_space &= CR3_ADDR_MASK;
-		flush->flags = 0;
 	} else {
-		flush->address_space = 0;
 		flush->flags = HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES;
 	}
 
-	flush->hv_vp_set.valid_bank_mask = 0;
-
 	flush->hv_vp_set.format = HV_GENERIC_SET_SPARSE_4K;
 	nr_bank = cpumask_to_vpset_skip(&flush->hv_vp_set, cpus,
 			info->freed_tables ? NULL : cpu_is_lazy);
@@ -210,10 +201,10 @@ static u64 hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
 	 * of flush->hv_vp_set as part of the fixed size input header.
 	 * So the variable input header size is equal to nr_bank.
 	 */
-	max_gvas =
-		(PAGE_SIZE - sizeof(*flush) - nr_bank *
-		 sizeof(flush->hv_vp_set.bank_contents[0])) /
+	max_gvas -= (nr_bank * sizeof(flush->hv_vp_set.bank_contents[0])) /
 		sizeof(flush->gva_list[0]);
+	if (max_gvas <= 0)
+		return HV_STATUS_INVALID_PARAMETER;
 
 	if (info->end == TLB_FLUSH_ALL) {
 		flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
diff --git a/arch/x86/hyperv/nested.c b/arch/x86/hyperv/nested.c
index 8ccbb7c4fc27..8eeda2e2ad29 100644
--- a/arch/x86/hyperv/nested.c
+++ b/arch/x86/hyperv/nested.c
@@ -30,15 +30,13 @@ int hyperv_flush_guest_mapping(u64 as)
 
 	local_irq_save(flags);
 
-	flush = *this_cpu_ptr(hyperv_pcpu_input_arg);
-
+	hv_setup_in(&flush, sizeof(*flush));
 	if (unlikely(!flush)) {
 		local_irq_restore(flags);
 		goto fault;
 	}
 
 	flush->address_space = as;
-	flush->flags = 0;
 
 	status = hv_do_hypercall(HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE,
 				 flush, NULL);
@@ -91,25 +89,23 @@ int hyperv_flush_guest_mapping_range(u64 as,
 	u64 status;
 	unsigned long flags;
 	int ret = -ENOTSUPP;
-	int gpa_n = 0;
+	int batch_size, gpa_n = 0;
 
 	if (!hv_hypercall_pg || !fill_flush_list_func)
 		goto fault;
 
 	local_irq_save(flags);
 
-	flush = *this_cpu_ptr(hyperv_pcpu_input_arg);
-
+	batch_size = hv_setup_in_array(&flush, sizeof(*flush),
+					sizeof(flush->gpa_list[0]));
 	if (unlikely(!flush)) {
 		local_irq_restore(flags);
 		goto fault;
 	}
 
 	flush->address_space = as;
-	flush->flags = 0;
-
 	gpa_n = fill_flush_list_func(flush, data);
-	if (gpa_n < 0) {
+	if (gpa_n < 0 || gpa_n > batch_size) {
 		local_irq_restore(flags);
 		goto fault;
 	}
diff --git a/include/hyperv/hvgdk_mini.h b/include/hyperv/hvgdk_mini.h
index 1be7f6a02304..5590b5fe318c 100644
--- a/include/hyperv/hvgdk_mini.h
+++ b/include/hyperv/hvgdk_mini.h
@@ -557,7 +557,7 @@ union hv_gpa_page_range {
 struct hv_guest_mapping_flush_list {
 	u64 address_space;
 	u64 flags;
-	union hv_gpa_page_range gpa_list[HV_MAX_FLUSH_REP_COUNT];
+	union hv_gpa_page_range gpa_list[];
 };
 
 struct hv_tlb_flush {	 /* HV_INPUT_FLUSH_VIRTUAL_ADDRESS_LIST */
@@ -1244,7 +1244,7 @@ struct hv_gpa_range_for_visibility {
 	u32 host_visibility : 2;
 	u32 reserved0 : 30;
 	u32 reserved1;
-	u64 gpa_page_list[HV_MAX_MODIFY_GPA_REP_COUNT];
+	u64 gpa_page_list[];
 } __packed;
 
 #if defined(CONFIG_X86)
-- 
2.25.1