HYGON: x86/amd_nb: Check vendor in AMD-only functions

commit b7a5cb4f220e78490735b2b984ad29b7d8e612a9 upstream.

Exit early in functions which are meant to run on AMD only but which get
run on different vendor (VMs, etc).

 [ bp: rewrite commit message. ]
Signed-off-by: NPu Wen <puwen@hygon.cn>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: bhelgaas@google.com
Cc: tglx@linutronix.de
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: x86@kernel.org
Cc: thomas.lendacky@amd.com
Cc: helgaas@kernel.org
Link: https://lkml.kernel.org/r/487d8078708baedaf63eb00a82251e228b58f1c2.1537885177.git.puwen@hygon.cnAcked-by: NCaspar Zhang <caspar@linux.alibaba.com>

arch/x86/include/asm/amd_nb.h

@@ -103,6 +103,9 @@ static inline u16 amd_pci_dev_to_node_id(struct pci_dev *pdev)
 
 static inline bool amd_gart_present(void)
 {
+	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
+		return false;
+
 	/* GART present only on Fam15h, upto model 0fh */
 	if (boot_cpu_data.x86 == 0xf || boot_cpu_data.x86 == 0x10 ||
 	    (boot_cpu_data.x86 == 0x15 && boot_cpu_data.x86_model < 0x10))

arch/x86/kernel/amd_nb.c

@@ -302,6 +302,10 @@ bool __init early_is_amd_nb(u32 device)
 	const struct pci_device_id *id;
 	u32 vendor = device & 0xffff;
 
+	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
+	    boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
+		return false;
+
 	device >>= 16;
 	for (id = amd_nb_misc_ids; id->vendor; id++)
 		if (vendor == id->vendor && device == id->device)