Drivers: hv vmbus: Move Hypercall page setup out of common code

As part of the effort to separate out architecture specific code, move the
hypercall page setup to an architecture specific file.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

MAINTAINERS

@@ -5962,6 +5962,7 @@ S:	Maintained
 F:	arch/x86/include/asm/mshyperv.h
 F:	arch/x86/include/uapi/asm/hyperv.h
 F:	arch/x86/kernel/cpu/mshyperv.c
+F:	arch/x86/hyperv
 F:	drivers/hid/hid-hyperv.c
 F:	drivers/hv/
 F:	drivers/input/serio/hyperv-keyboard.c

arch/x86/Kbuild

@@ -7,6 +7,9 @@ obj-$(CONFIG_KVM) += kvm/
 # Xen paravirtualization support
 obj-$(CONFIG_XEN) += xen/
 
+# Hyper-V paravirtualization support
+obj-$(CONFIG_HYPERVISOR_GUEST) += hyperv/
+
 # lguest paravirtualization support
 obj-$(CONFIG_LGUEST_GUEST) += lguest/
 

arch/x86/hyperv/Makefile

+obj-y		:= hv_init.o

arch/x86/hyperv/hv_init.c

+/*
+ * X86 specific Hyper-V initialization code.
+ *
+ * Copyright (C) 2016, Microsoft, Inc.
+ *
+ * Author : K. Y. Srinivasan <kys@microsoft.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT.  See the GNU General Public License for more
+ * details.
+ *
+ */
+
+#include <linux/types.h>
+#include <asm/hypervisor.h>
+#include <asm/hyperv.h>
+#include <asm/mshyperv.h>
+#include <linux/version.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+
+void *hv_hypercall_pg;
+/*
+ * This function is to be invoked early in the boot sequence after the
+ * hypervisor has been detected.
+ *
+ * 1. Setup the hypercall page.
+ */
+void hyperv_init(void)
+{
+	u64 guest_id;
+	union hv_x64_msr_hypercall_contents hypercall_msr;
+
+	if (x86_hyper != &x86_hyper_ms_hyperv)
+		return;
+
+	/*
+	 * Setup the hypercall page and enable hypercalls.
+	 * 1. Register the guest ID
+	 * 2. Enable the hypercall and register the hypercall page
+	 */
+	guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);
+	wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
+
+	hv_hypercall_pg  = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_EXEC);
+	if (hv_hypercall_pg == NULL) {
+		wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
+		return;
+	}
+
+	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+	hypercall_msr.enable = 1;
+	hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
+	wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+}
+EXPORT_SYMBOL_GPL(hv_hypercall_pg);

arch/x86/include/asm/mshyperv.h

@@ -80,4 +80,9 @@ void hv_setup_kexec_handler(void (*handler)(void));
 void hv_remove_kexec_handler(void);
 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs));
 void hv_remove_crash_handler(void);
+
+#if IS_ENABLED(CONFIG_HYPERV)
+void hyperv_init(void);
+extern void *hv_hypercall_pg;
+#endif
 #endif

arch/x86/kernel/cpu/mshyperv.c

@@ -227,6 +227,13 @@ static void __init ms_hyperv_init_platform(void)
 	 */
 	if (efi_enabled(EFI_BOOT))
 		x86_platform.get_nmi_reason = hv_get_nmi_reason;
+
+#if IS_ENABLED(CONFIG_HYPERV)
+	/*
+	 * Setup the hook to get control post apic initialization.
+	 */
+	x86_platform.apic_post_init = hyperv_init;
+#endif
 }
 
 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {

drivers/hv/hv.c

@@ -193,7 +193,6 @@ int hv_init(void)
 {
 	int max_leaf;
 	union hv_x64_msr_hypercall_contents hypercall_msr;
-	void *virtaddr = NULL;
 
 	memset(hv_context.synic_event_page, 0, sizeof(void *) * NR_CPUS);
 	memset(hv_context.synic_message_page, 0,
@@ -211,33 +210,15 @@ int hv_init(void)
 
 	max_leaf = query_hypervisor_info();
 
-	/*
-	 * Write our OS ID.
-	 */
-	hv_context.guestid = generate_guest_id(0, LINUX_VERSION_CODE, 0);
-	wrmsrl(HV_X64_MSR_GUEST_OS_ID, hv_context.guestid);
 
 	/* See if the hypercall page is already set */
-	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
-
-	virtaddr = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_EXEC);
-
-	if (!virtaddr)
-		goto cleanup;
-
-	hypercall_msr.enable = 1;
-
-	hypercall_msr.guest_physical_address = vmalloc_to_pfn(virtaddr);
-	wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
-
-	/* Confirm that hypercall page did get setup. */
 	hypercall_msr.as_uint64 = 0;
 	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 
 	if (!hypercall_msr.enable)
-		goto cleanup;
+		return -ENOTSUPP;
 
-	hv_context.hypercall_page = virtaddr;
+	hv_context.hypercall_page = hv_hypercall_pg;
 
 #ifdef CONFIG_X86_64
 	if (ms_hyperv.features & HV_X64_MSR_REFERENCE_TSC_AVAILABLE) {
@@ -261,15 +242,6 @@ int hv_init(void)
 	return 0;
 
 cleanup:
-	if (virtaddr) {
-		if (hypercall_msr.enable) {
-			hypercall_msr.as_uint64 = 0;
-			wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
-		}
-
-		vfree(virtaddr);
-	}
-
 	return -ENOTSUPP;
 }
 
@@ -280,20 +252,9 @@ int hv_init(void)
  */
 void hv_cleanup(bool crash)
 {
-	union hv_x64_msr_hypercall_contents hypercall_msr;
-
-	/* Reset our OS id */
-	wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
-
-	if (hv_context.hypercall_page) {
-		hypercall_msr.as_uint64 = 0;
-		wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
-		if (!crash)
-			vfree(hv_context.hypercall_page);
-		hv_context.hypercall_page = NULL;
-	}
 
 #ifdef CONFIG_X86_64
+	union hv_x64_msr_hypercall_contents hypercall_msr;
 	/*
 	 * Cleanup the TSC page based CS.
 	 */