1 files changed, 49 insertions, 5 deletions

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 3206bfda586d..b5c8e04deacb 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -25,7 +25,7 @@
 #include <linux/vmalloc.h>
 #include <linux/mm.h>
 
-void *hv_hypercall_pg;
+static void *hypercall_pg;
 /*
  * This function is to be invoked early in the boot sequence after the
  * hypervisor has been detected.
@@ -48,15 +48,59 @@ void hyperv_init(void)
 	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) {
+	hypercall_pg  = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_EXEC);
+	if (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);
+	hypercall_msr.guest_physical_address = vmalloc_to_pfn(hypercall_pg);
 	wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 }
-EXPORT_SYMBOL_GPL(hv_hypercall_pg);
+
+/*
+ * hv_do_hypercall- Invoke the specified hypercall
+ */
+u64 hv_do_hypercall(u64 control, void *input, void *output)
+{
+	u64 input_address = (input) ? virt_to_phys(input) : 0;
+	u64 output_address = (output) ? virt_to_phys(output) : 0;
+#ifdef CONFIG_X86_64
+	u64 hv_status = 0;
+
+	if (!hypercall_pg)
+		return (u64)ULLONG_MAX;
+
+	__asm__ __volatile__("mov %0, %%r8" : : "r" (output_address) : "r8");
+	__asm__ __volatile__("call *%3" : "=a" (hv_status) :
+			     "c" (control), "d" (input_address),
+			     "m" (hypercall_pg));
+
+	return hv_status;
+
+#else
+
+	u32 control_hi = control >> 32;
+	u32 control_lo = control & 0xFFFFFFFF;
+	u32 hv_status_hi = 1;
+	u32 hv_status_lo = 1;
+	u32 input_address_hi = input_address >> 32;
+	u32 input_address_lo = input_address & 0xFFFFFFFF;
+	u32 output_address_hi = output_address >> 32;
+	u32 output_address_lo = output_address & 0xFFFFFFFF;
+
+	if (!hypercall_pg)
+		return (u64)ULLONG_MAX;
+
+	__asm__ __volatile__ ("call *%8" : "=d"(hv_status_hi),
+			      "=a"(hv_status_lo) : "d" (control_hi),
+			      "a" (control_lo), "b" (input_address_hi),
+			      "c" (input_address_lo), "D"(output_address_hi),
+			      "S"(output_address_lo), "m" (hypercall_pg));
+
+	return hv_status_lo | ((u64)hv_status_hi << 32);
+#endif /* !x86_64 */
+}
+EXPORT_SYMBOL_GPL(hv_do_hypercall);