i386/pc_sysfw: Ensure sysfw flash configuration does not conflict with IGVM

When using an IGVM file the configuration of the system firmware is
defined by IGVM directives contained in the file. In this case the user
should not configure any pflash devices.

This commit skips initialization of the ROM mode when pflash0 is not set
then checks to ensure no pflash devices have been configured when using
IGVM, exiting with an error message if this is not the case.

Signed-off-by: Roy Hopkins <roy.hopkins@randomman.co.uk>
Acked-by: Gerd Hoffman <kraxel@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>
Reviewed-by: Ani Sinha <anisinha@redhat.com>
Link: https://lore.kernel.org/r/c6166cfe128933b04003a9288566b7affe170dfe.1751554099.git.roy.hopkins@randomman.co.uk
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
index 821396c16e91d7bd933300b25f5298b82f128f32..1a12b635ad98dd8a8b85711073fa4f9cd5328f27 100644 (file)
--- a/hw/i386/pc_sysfw.c
+++ b/hw/i386/pc_sysfw.c
@@ -220,7 +220,13 @@ void pc_system_firmware_init(PCMachineState *pcms,
     BlockBackend *pflash_blk[ARRAY_SIZE(pcms->flash)];
 
     if (!pcmc->pci_enabled) {
-        x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, true);
+        /*
+         * If an IGVM file is specified then the firmware must be provided
+         * in the IGVM file.
+         */
+        if (!X86_MACHINE(pcms)->igvm) {
+            x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, true);
+        }
         return;
     }
 
@@ -240,8 +246,13 @@ void pc_system_firmware_init(PCMachineState *pcms,
     }
 
     if (!pflash_blk[0]) {
-        /* Machine property pflash0 not set, use ROM mode */
-        x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, false);
+        /*
+         * Machine property pflash0 not set, use ROM mode unless using IGVM,
+         * in which case the firmware must be provided by the IGVM file.
+         */
+        if (!X86_MACHINE(pcms)->igvm) {
+            x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, false);
+        }
     } else {
         if (kvm_enabled() && !kvm_readonly_mem_enabled()) {
             /*
@@ -257,6 +268,20 @@ void pc_system_firmware_init(PCMachineState *pcms,
     }
 
     pc_system_flash_cleanup_unused(pcms);
+
+    /*
+     * The user should not have specified any pflash devices when using IGVM
+     * to configure the guest.
+     */
+    if (X86_MACHINE(pcms)->igvm) {
+        for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
+            if (pcms->flash[i]) {
+                error_report("pflash devices cannot be configured when "
+                             "using IGVM");
+                exit(1);
+            }
+        }
+    }
 }
 
 void x86_firmware_configure(hwaddr gpa, void *ptr, int size)