hyperv: simplify and rename generate_guest_id

The generate_guest_id function is more suitable for use after the
following modifications.

1. The return value of the function is modified to u64.
2. Remove the d_info1 and d_info2 parameters from the function, keep the
   u64 type kernel_version parameter.
3. Rename the function to make it clearly a Hyper-V related function,
   and modify it to hv_generate_guest_id.
Signed-off-by: Li kunyu <kunyu@nfschina.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20220928064046.3545-1-kunyu@nfschina.comSigned-off-by: Wei Liu <wei.liu@kernel.org>

arch/arm64/hyperv/mshyperv.c

@@ -38,7 +38,7 @@ static int __init hyperv_init(void)
 		return 0;
 
 	/* Setup the guest ID */
-	guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);
+	guest_id = hv_generate_guest_id(LINUX_VERSION_CODE);
 	hv_set_vpreg(HV_REGISTER_GUEST_OSID, guest_id);
 
 	/* Get the features and hints from Hyper-V */

arch/x86/hyperv/hv_init.c

@@ -426,7 +426,7 @@ void __init hyperv_init(void)
 	 * 1. Register the guest ID
 	 * 2. Enable the hypercall and register the hypercall page
 	 */
-	guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);
+	guest_id = hv_generate_guest_id(LINUX_VERSION_CODE);
 	wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
 
 	/* Hyper-V requires to write guest os id via ghcb in SNP IVM. */

include/asm-generic/mshyperv.h

@@ -105,15 +105,12 @@ static inline u64 hv_do_rep_hypercall(u16 code, u16 rep_count, u16 varhead_size,
 }
 
 /* Generate the guest OS identifier as described in the Hyper-V TLFS */
-static inline  __u64 generate_guest_id(__u64 d_info1, __u64 kernel_version,
-				       __u64 d_info2)
+static inline u64 hv_generate_guest_id(u64 kernel_version)
 {
-	__u64 guest_id = 0;
+	u64 guest_id;
 
-	guest_id = (((__u64)HV_LINUX_VENDOR_ID) << 48);
-	guest_id |= (d_info1 << 48);
+	guest_id = (((u64)HV_LINUX_VENDOR_ID) << 48);
 	guest_id |= (kernel_version << 16);
-	guest_id |= d_info2;
 
 	return guest_id;
 }