qemu: add disgusting hacks for RHEL 8

Red Hat does awful things to their kernel for RHEL 8, such that it
doesn't even compile in most configurations. This is utter craziness,
and their response to me sending patches to fix this stuff has been to
stonewall for months on end and then do nothing.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

Author: zx2c4

src/tests/qemu/Makefile

@@ -276,7 +276,13 @@ $(KERNEL_PATH)/.installed: $(KERNEL_TAR)
 	sed -i '/jmp early_idt_handler$$/a .fill early_idt_handlers + i*9 - ., 1, 0xcc' $(KERNEL_PATH)/arch/x86/kernel/head_{64,32}.S || true
 	printf 'ifdef CONFIG_X86_64\nLDFLAGS += $$(call ld-option, -z max-page-size=0x200000)\nendif\n' >> $(KERNEL_PATH)/arch/x86/Makefile
 	sed -i 's/^Elf_Addr per_cpu_load_addr;$$/static \0/' $(KERNEL_PATH)/arch/x86/tools/relocs.c || true
-	if grep -qr UTS_UBUNTU_RELEASE_ABI $(KERNEL_PATH)/debian/rules.d; then echo 'KBUILD_CFLAGS += -DUTS_UBUNTU_RELEASE_ABI=0' >> $(KERNEL_PATH)/Makefile; fi
+	if grep -sqr UTS_UBUNTU_RELEASE_ABI $(KERNEL_PATH)/debian/rules.d; then echo 'KBUILD_CFLAGS += -DUTS_UBUNTU_RELEASE_ABI=0' >> $(KERNEL_PATH)/Makefile; fi
+	if grep -sq 'RHEL_MAJOR = 8' $(KERNEL_PATH)/Makefile.rhelver; then \
+		sed -i '/#include <asm\//a #include <asm\/acpi.h>/' $(KERNEL_PATH)/arch/x86/kernel/{apic/apic.c,irqinit.c,kvm.c,mpparse.c} && \
+		sed -i '/#include <asm\//a #include <asm\/numa.h>/' $(KERNEL_PATH)/arch/x86/kernel/setup.c && \
+		sed -i '/irq_hv_callback_count/d' $(KERNEL_PATH)/arch/x86/kernel/kvm.c && \
+		sed -i '/do_vmm_communication/d' $(KERNEL_PATH)/arch/x86/entry/entry_64.S \
+	fi
 	sed -i "/^if INET\$$/a source \"net/wireguard/Kconfig\"" $(KERNEL_PATH)/net/Kconfig
 	sed -i "/^obj-\$$(CONFIG_NETFILTER).*+=/a obj-\$$(CONFIG_WIREGUARD) += wireguard/" $(KERNEL_PATH)/net/Makefile
 	ln -sfT $(shell readlink -f ../..) $(KERNEL_PATH)/net/wireguard