hw/riscv/virt.c: fix non-KVM --enable-debug build

A build with --enable-debug and without KVM will fail as follows:

/usr/bin/ld: libqemu-riscv64-softmmu.fa.p/hw_riscv_virt.c.o: in function `virt_machine_init':
./qemu/build/../hw/riscv/virt.c:1465: undefined reference to `kvm_riscv_aia_create'

This happens because the code block with "if virt_use_kvm_aia(s)" isn't
being ignored by the debug build, resulting in an undefined reference to
a KVM only function.

Add a 'kvm_enabled()' conditional together with virt_use_kvm_aia() will
make the compiler crop the kvm_riscv_aia_create() call entirely from a
non-KVM build. Note that adding the 'kvm_enabled()' conditional inside
virt_use_kvm_aia() won't fix the build because this function would need
to be inlined multiple times to make the compiler zero out the entire
block.

While we're at it, use kvm_enabled() in all instances where
virt_use_kvm_aia() is checked to allow the compiler to elide these other
kvm-only instances as well.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Fixes: dbdb999 ("target/riscv: select KVM AIA in riscv virt machine")
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20230830133503.711138-2-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

hw/riscv/virt.c

@@ -782,7 +782,7 @@ static void create_fdt_sockets(RISCVVirtState *s, const MemMapEntry *memmap,
     }
 
     /* KVM AIA only has one APLIC instance */
-    if (virt_use_kvm_aia(s)) {
+    if (kvm_enabled() && virt_use_kvm_aia(s)) {
         create_fdt_socket_aplic(s, memmap, 0,
                                 msi_m_phandle, msi_s_phandle, phandle,
                                 &intc_phandles[0], xplic_phandles,
@@ -808,7 +808,7 @@ static void create_fdt_sockets(RISCVVirtState *s, const MemMapEntry *memmap,
 
     g_free(intc_phandles);
 
-    if (virt_use_kvm_aia(s)) {
+    if (kvm_enabled() && virt_use_kvm_aia(s)) {
         *irq_mmio_phandle = xplic_phandles[0];
         *irq_virtio_phandle = xplic_phandles[0];
         *irq_pcie_phandle = xplic_phandles[0];
@@ -1461,7 +1461,7 @@ static void virt_machine_init(MachineState *machine)
         }
     }
 
-    if (virt_use_kvm_aia(s)) {
+    if (kvm_enabled() && virt_use_kvm_aia(s)) {
         kvm_riscv_aia_create(machine, IMSIC_MMIO_GROUP_MIN_SHIFT,
                              VIRT_IRQCHIP_NUM_SOURCES, VIRT_IRQCHIP_NUM_MSIS,
                              memmap[VIRT_APLIC_S].base,