x86/vmware: Parse MP tables for SEV-SNP enabled guests under VMware hypervisors

Under VMware hypervisors, SEV-SNP enabled VMs are fundamentally able to boot
without UEFI, but this regressed a year ago due to:

  0f4a1e8 ("x86/sev: Skip ROM range scans and validation for SEV-SNP guests")

In this case, mpparse_find_mptable() has to be called to parse MP
tables which contains the necessary boot information.

[ mingo: Updated the changelog. ]

Fixes: 0f4a1e8 ("x86/sev: Skip ROM range scans and validation for SEV-SNP guests")
Co-developed-by: Ye Li <ye.li@broadcom.com>
Signed-off-by: Ye Li <ye.li@broadcom.com>
Signed-off-by: Ajay Kaher <ajay.kaher@broadcom.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Ye Li <ye.li@broadcom.com>
Reviewed-by: Kevin Loughlin <kevinloughlin@google.com>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20250313173111.10918-1-ajay.kaher@broadcom.com

Author: akaher

arch/x86/kernel/cpu/vmware.c

@@ -26,6 +26,7 @@
 #include <linux/export.h>
 #include <linux/clocksource.h>
 #include <linux/cpu.h>
+#include <linux/efi.h>
 #include <linux/reboot.h>
 #include <linux/static_call.h>
 #include <asm/div64.h>
@@ -429,6 +430,9 @@ static void __init vmware_platform_setup(void)
 		pr_warn("Failed to get TSC freq from the hypervisor\n");
 	}
 
+	if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) && !efi_enabled(EFI_BOOT))
+		x86_init.mpparse.find_mptable = mpparse_find_mptable;
+
 	vmware_paravirt_ops_setup();
 
 #ifdef CONFIG_X86_IO_APIC