From c6d56081c9dca474130c0b34c39451b21c55102f Mon Sep 17 00:00:00 2001
From: Warner Losh <imp@FreeBSD.org>
Date: Fri, 9 Oct 2020 00:16:26 +0000
Subject: [PATCH] Initial support for implementing the bootXXX.efi workaround

Too many version of UEFI firmware (so far only confirmed on amd64)
don't really support efibootmgr selection of boot. That's the most
reliable, when it works, since there's no guesswork. However, many do
not save, unmolested, the variables that efibootmgr sets, so as a
fallback we also install loader.efi as bootXXX.efi (where XXX is
either aa64 or x64) if it doesn't already exist in /efi/boot on the
ESP. The standard only defines this for removable devices, but it's
almost ubiquitously used as a fallback. Many BIOSes implement a drive
selection feature that takes over the efibootmgr protocol, rendinering
it useless (either generally, or for those vendors not on the short
list). bootxxx.efi works around this. However, we don't install it
unconditionally there, as that breaks some popular multi-boot setups.

MFC After: 1 week
Differential Revision: https://reviews.freebsd.org/D26428
---
 usr.sbin/bsdinstall/scripts/bootconfig | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/usr.sbin/bsdinstall/scripts/bootconfig b/usr.sbin/bsdinstall/scripts/bootconfig
index 944a2f10681a..93a3bc0a53c2 100755
--- a/usr.sbin/bsdinstall/scripts/bootconfig
+++ b/usr.sbin/bsdinstall/scripts/bootconfig
@@ -124,6 +124,15 @@ if [ "$(uname -m)" = "arm64" ] || [ "$X86_BOOTMETHOD" = "UEFI" ]; then
 		done
 	fi
 
+	case $(uname -m) in
+	    arm64)	ARCHBOOTNAME=aa64 ;;
+	    amd64)	ARCHBOOTNAME=x64 ;;
+    #	    arm)	ARCHBOOTNAME=arm ;; # No other support for arm install
+    #	    i386)	ARCHBOOTNAME=ia32 ;; # no support for this in i386 kernels, rare machines
+	    *)		die "Unsupported arch $(uname -m) for UEFI install"
+	esac
+	BOOTNAME="/EFI/BOOT/BOOT${ARCHBOOTNAME}.EFI"
+
 	for esp in $ESPS; do
 		f_dprintf "Formatting /dev/${esp} as FAT32"
 		newfs_msdos -F 32 -c 1 -L EFISYS "/dev/$esp" > /dev/null 2>&1
@@ -142,6 +151,21 @@ if [ "$(uname -m)" = "arm64" ] || [ "$X86_BOOTMETHOD" = "UEFI" ]; then
 		mkdir -p "$mntpt/EFI/freebsd"
 		cp "$BSDINSTALL_CHROOT/boot/loader.efi" "${mntpt}/EFI/freebsd/loader.efi"
 
+		#
+		# The following shouldn't be necessary. UEFI defines a way to
+		# specifically select what to boot (which we do via
+		# efibootmgr). However, virtual environments often times lack
+		# support for the NV variables efibootmgr sets. In addition,
+		# some UEFI implementations have features that interfere with
+		# the setting of these variables. To combat that, we install the
+		# default removable media boot file as a fallback if it doesn't
+		# exist. We don't install it all the time since that can
+		# interfere with other installations on the drive (like rEFInd).
+		#
+		if [ ! -f "${mntpt}/${BOOTNAME}" ]; then
+			cp "$BSDINSTALL_CHROOT/boot/loader.efi" "${mntpt}/${BOOTNAME}"
+		fi
+
 		if [ "$num_esps" -gt 1 ]; then
 			bootlabel="FreeBSD (${esp})"
 		else