It's not clear this is needed - Linux doesn't use the MPS table even if
available, and no system having one was seen so far.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

--- a/xen/arch/x86/efi/boot.c
+++ b/xen/arch/x86/efi/boot.c
@@ -897,12 +897,15 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SY
     {
         static EFI_GUID __initdata acpi2_guid = ACPI_20_TABLE_GUID;
         static EFI_GUID __initdata acpi_guid = ACPI_TABLE_GUID;
+        static EFI_GUID __initdata mps_guid = MPS_TABLE_GUID;
         static EFI_GUID __initdata smbios_guid = SMBIOS_TABLE_GUID;
 
         if ( match_guid(&acpi2_guid, &efi_ct[i].VendorGuid) )
 	       efi.acpi20 = (long)efi_ct[i].VendorTable;
         if ( match_guid(&acpi_guid, &efi_ct[i].VendorGuid) )
 	       efi.acpi = (long)efi_ct[i].VendorTable;
+        if ( match_guid(&mps_guid, &efi_ct[i].VendorGuid) )
+	       efi.mps = (long)efi_ct[i].VendorTable;
         if ( match_guid(&smbios_guid, &efi_ct[i].VendorGuid) )
 	       efi.smbios = (long)efi_ct[i].VendorTable;
     }
--- a/xen/arch/x86/efi/runtime.c
+++ b/xen/arch/x86/efi/runtime.c
@@ -29,6 +29,7 @@ void *__read_mostly efi_memmap;
 struct efi __read_mostly efi = {
 	.acpi   = EFI_INVALID_TABLE_ADDR,
 	.acpi20 = EFI_INVALID_TABLE_ADDR,
+	.mps    = EFI_INVALID_TABLE_ADDR,
 	.smbios = EFI_INVALID_TABLE_ADDR,
 };
 
--- a/xen/arch/x86/mpparse.c
+++ b/xen/arch/x86/mpparse.c
@@ -19,6 +19,7 @@
 #include <xen/init.h>
 #include <xen/acpi.h>
 #include <xen/delay.h>
+#include <xen/efi.h>
 #include <xen/sched.h>
 
 #include <asm/bitops.h>
@@ -514,6 +515,14 @@ static inline void __init construct_defa
 	}
 }
 
+#define FIX_EFI_MPF FIX_KEXEC_BASE_0
+
+static __init void efi_unmap_mpf(void)
+{
+	if (efi_enabled)
+		__set_fixmap(FIX_EFI_MPF, 0, 0);
+}
+
 static struct intel_mp_floating *__initdata mpf_found;
 
 /*
@@ -528,6 +537,7 @@ void __init get_smp_config (void)
 	 * processors, where MPS only supports physical.
 	 */
 	if (acpi_lapic && acpi_ioapic) {
+		efi_unmap_mpf();
 		printk(KERN_INFO "Using ACPI (MADT) for SMP configuration information\n");
 		return;
 	}
@@ -558,6 +568,7 @@ void __init get_smp_config (void)
 		 * override the defaults.
 		 */
 		if (!smp_read_mpc((void *)(unsigned long)mpf->mpf_physptr)) {
+			efi_unmap_mpf();
 			smp_found_config = 0;
 			printk(KERN_ERR "BIOS bug, MP table errors detected!...\n");
 			printk(KERN_ERR "... disabling SMP support. (tell your hw vendor)\n");
@@ -584,6 +595,8 @@ void __init get_smp_config (void)
 	} else
 		BUG();
 
+	efi_unmap_mpf();
+
 	printk(KERN_INFO "Processors: %d\n", num_processors);
 	/*
 	 * Only use the first configuration found.
@@ -638,10 +651,37 @@ static int __init smp_scan_config (unsig
 	return 0;
 }
 
+static void __init efi_check_config(void)
+{
+	struct intel_mp_floating *mpf;
+
+	if (efi.mps == EFI_INVALID_TABLE_ADDR)
+		return;
+
+	__set_fixmap(FIX_EFI_MPF, PFN_DOWN(efi.mps), __PAGE_HYPERVISOR);
+	mpf = (void *)fix_to_virt(FIX_EFI_MPF) + ((long)efi.mps & (PAGE_SIZE-1));
+
+	if (memcmp(mpf->mpf_signature, "_MP_", 4) == 0 &&
+	    mpf->mpf_length == 1 &&
+	    mpf_checksum((void *)mpf, 16) &&
+	    (mpf->mpf_specification == 1 || mpf->mpf_specification == 4)) {
+		smp_found_config = 1;
+		printk(KERN_INFO "SMP MP-table at %08"PRIx64"\n", efi.mps);
+		mpf_found = mpf;
+	}
+	else
+		efi_unmap_mpf();
+}
+
 void __init find_smp_config (void)
 {
 	unsigned int address;
 
+	if (efi_enabled) {
+		efi_check_config();
+		return;
+	}
+
 	/*
 	 * FIXME: Linux assumes you have 640K of base ram..
 	 * this continues the error...
--- a/xen/include/xen/efi.h
+++ b/xen/include/xen/efi.h
@@ -17,6 +17,7 @@ extern const bool_t efi_enabled;
 
 /* Add fields here only if they need to be referenced from non-EFI code. */
 struct efi {
+    unsigned long mps;          /* MPS table */
     unsigned long acpi;         /* ACPI table (IA64 ext 0.71) */
     unsigned long acpi20;       /* ACPI table (ACPI 2.0) */
     unsigned long smbios;       /* SM BIOS table */