Drivers: hv: Make portions of Hyper-V init code be arch neutral

The code to allocate and initialize the hv_vp_index array is
architecture neutral. Similarly, the code to allocate and
populate the hypercall input and output arg pages is architecture
neutral.  Move both sets of code out from arch/x86 and into
utility functions in drivers/hv/hv_common.c that can be shared
by Hyper-V initialization on ARM64.

No functional changes. However, the allocation of the hypercall
input and output arg pages is done differently so that the
size is always the Hyper-V page size, even if not the same as
the guest page size (such as with ARM64's 64K page size).

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1626287687-2045-2-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>

1 files changed, 10 insertions, 81 deletions

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 6952e219cba3..5cc0c0f30e75 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -39,48 +39,17 @@ EXPORT_SYMBOL_GPL(hv_hypercall_pg);
 /* Storage to save the hypercall page temporarily for hibernation */
 static void *hv_hypercall_pg_saved;
 
-u32 *hv_vp_index;
-EXPORT_SYMBOL_GPL(hv_vp_index);
-
 struct hv_vp_assist_page **hv_vp_assist_page;
 EXPORT_SYMBOL_GPL(hv_vp_assist_page);
 
-void  __percpu **hyperv_pcpu_input_arg;
-EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg);
-
-void  __percpu **hyperv_pcpu_output_arg;
-EXPORT_SYMBOL_GPL(hyperv_pcpu_output_arg);
-
-u32 hv_max_vp_index;
-EXPORT_SYMBOL_GPL(hv_max_vp_index);
-
 static int hv_cpu_init(unsigned int cpu)
 {
-	u64 msr_vp_index;
 	struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()];
-	void **input_arg;
-	struct page *pg;
-
-	/* hv_cpu_init() can be called with IRQs disabled from hv_resume() */
-	pg = alloc_pages(irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL, hv_root_partition ? 1 : 0);
-	if (unlikely(!pg))
-		return -ENOMEM;
-
-	input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
-	*input_arg = page_address(pg);
-	if (hv_root_partition) {
-		void **output_arg;
-
-		output_arg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
-		*output_arg = page_address(pg + 1);
-	}
-
-	msr_vp_index = hv_get_register(HV_REGISTER_VP_INDEX);
-
-	hv_vp_index[smp_processor_id()] = msr_vp_index;
+	int ret;
 
-	if (msr_vp_index > hv_max_vp_index)
-		hv_max_vp_index = msr_vp_index;
+	ret = hv_common_cpu_init(cpu);
+	if (ret)
+		return ret;
 
 	if (!hv_vp_assist_page)
 		return 0;
@@ -198,25 +167,8 @@ static int hv_cpu_die(unsigned int cpu)
 {
 	struct hv_reenlightenment_control re_ctrl;
 	unsigned int new_cpu;
-	unsigned long flags;
-	void **input_arg;
-	void *pg;
 
-	local_irq_save(flags);
-	input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
-	pg = *input_arg;
-	*input_arg = NULL;
-
-	if (hv_root_partition) {
-		void **output_arg;
-
-		output_arg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
-		*output_arg = NULL;
-	}
-
-	local_irq_restore(flags);
-
-	free_pages((unsigned long)pg, hv_root_partition ? 1 : 0);
+	hv_common_cpu_die(cpu);
 
 	if (hv_vp_assist_page && hv_vp_assist_page[cpu])
 		wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, 0);
@@ -368,7 +320,7 @@ void __init hyperv_init(void)
 {
 	u64 guest_id, required_msrs;
 	union hv_x64_msr_hypercall_contents hypercall_msr;
-	int cpuhp, i;
+	int cpuhp;
 
 	if (x86_hyper_type != X86_HYPER_MS_HYPERV)
 		return;
@@ -380,36 +332,14 @@ void __init hyperv_init(void)
 	if ((ms_hyperv.features & required_msrs) != required_msrs)
 		return;
 
-	/*
-	 * Allocate the per-CPU state for the hypercall input arg.
-	 * If this allocation fails, we will not be able to setup
-	 * (per-CPU) hypercall input page and thus this failure is
-	 * fatal on Hyper-V.
-	 */
-	hyperv_pcpu_input_arg = alloc_percpu(void  *);
-
-	BUG_ON(hyperv_pcpu_input_arg == NULL);
-
-	/* Allocate the per-CPU state for output arg for root */
-	if (hv_root_partition) {
-		hyperv_pcpu_output_arg = alloc_percpu(void *);
-		BUG_ON(hyperv_pcpu_output_arg == NULL);
-	}
-
-	/* Allocate percpu VP index */
-	hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index),
-				    GFP_KERNEL);
-	if (!hv_vp_index)
+	if (hv_common_init())
 		return;
 
-	for (i = 0; i < num_possible_cpus(); i++)
-		hv_vp_index[i] = VP_INVAL;
-
 	hv_vp_assist_page = kcalloc(num_possible_cpus(),
 				    sizeof(*hv_vp_assist_page), GFP_KERNEL);
 	if (!hv_vp_assist_page) {
 		ms_hyperv.hints &= ~HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
-		goto free_vp_index;
+		goto common_free;
 	}
 
 	cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
@@ -507,9 +437,8 @@ remove_cpuhp_state:
 free_vp_assist_page:
 	kfree(hv_vp_assist_page);
 	hv_vp_assist_page = NULL;
-free_vp_index:
-	kfree(hv_vp_index);
-	hv_vp_index = NULL;
+common_free:
+	hv_common_free();
 }
 
 /*