Re: [PATCH 2/2] xen: cleanup unrealized flash devices

[Philippe Mathieu-Daudé]

On 6/24/20 2:18 PM, Paul Durrant wrote:
> From: Paul Durrant <pdurrant@amazon.com>
> 
> The generic pc_machine_initfn() calls pc_system_flash_create() which creates
> 'system.flash0' and 'system.flash1' devices. These devices are then realized
> by pc_system_flash_map() which is called from pc_system_firmware_init() which
> itself is called via pc_memory_init(). The latter however is not called when
> xen_enable() is true and hence the following assertion fails:
> 
> qemu-system-i386: hw/core/qdev.c:439: qdev_assert_realized_properly:
> Assertion `dev->realized' failed
> 
> These flash devices are unneeded when using Xen so this patch avoids the
> assertion by simply removing them using pc_system_flash_cleanup_unused().
> 
> Reported-by: Jason Andryuk <jandryuk@gmail.com>
> Fixes: ebc29e1beab0 ("pc: Support firmware configuration with -blockdev")
> Signed-off-by: Paul Durrant <pdurrant@amazon.com>
> Tested-by: Jason Andryuk <jandryuk@gmail.com>
> ---
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Richard Henderson <rth@twiddle.net>
> Cc: Eduardo Habkost <ehabkost@redhat.com>
> Cc: "Michael S. Tsirkin" <mst@redhat.com>
> Cc: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
> ---
>  hw/i386/pc_piix.c    | 9 ++++++---
>  hw/i386/pc_sysfw.c   | 2 +-
>  include/hw/i386/pc.h | 1 +
>  3 files changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index 1497d0e4ae..977d40afb8 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -186,9 +186,12 @@ static void pc_init1(MachineState *machine,
>      if (!xen_enabled()) {
>          pc_memory_init(pcms, system_memory,
>                         rom_memory, &ram_memory);
> -    } else if (machine->kernel_filename != NULL) {
> -        /* For xen HVM direct kernel boot, load linux here */
> -        xen_load_linux(pcms);
> +    } else {
> +        pc_system_flash_cleanup_unused(pcms);

TIL pc_system_flash_cleanup_unused().

What about restricting at the source?

-- >8 --
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1004,24 +1004,26 @@ void pc_memory_init(PCMachineState *pcms,
                                     &machine->device_memory->mr);
     }

-    /* Initialize PC system firmware */
-    pc_system_firmware_init(pcms, rom_memory);
-
-    option_rom_mr = g_malloc(sizeof(*option_rom_mr));
-    memory_region_init_ram(option_rom_mr, NULL, "pc.rom", PC_ROM_SIZE,
-                           &error_fatal);
-    if (pcmc->pci_enabled) {
-        memory_region_set_readonly(option_rom_mr, true);
-    }
-    memory_region_add_subregion_overlap(rom_memory,
-                                        PC_ROM_MIN_VGA,
-                                        option_rom_mr,
-                                        1);
-
     fw_cfg = fw_cfg_arch_create(machine,
                                 x86ms->boot_cpus, x86ms->apic_id_limit);

-    rom_set_fw(fw_cfg);
+    /* Initialize PC system firmware */
+    if (!xen_enabled()) {
+        pc_system_firmware_init(pcms, rom_memory);
+
+        option_rom_mr = g_malloc(sizeof(*option_rom_mr));
+        memory_region_init_ram(option_rom_mr, NULL, "pc.rom", PC_ROM_SIZE,
+                               &error_fatal);
+        if (pcmc->pci_enabled) {
+            memory_region_set_readonly(option_rom_mr, true);
+        }
+        memory_region_add_subregion_overlap(rom_memory,
+                                            PC_ROM_MIN_VGA,
+                                            option_rom_mr,
+                                            1);
+
+        rom_set_fw(fw_cfg);
+    }

     if (pcmc->has_reserved_memory && machine->device_memory->base) {
         uint64_t *val = g_malloc(sizeof(*val));
---

> +        if (machine->kernel_filename != NULL) {
> +            /* For xen HVM direct kernel boot, load linux here */
> +            xen_load_linux(pcms);
> +        }
>      }
>  
>      gsi_state = pc_gsi_create(&x86ms->gsi, pcmc->pci_enabled);
> diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
> index ec2a3b3e7e..0ff47a4b59 100644
> --- a/hw/i386/pc_sysfw.c
> +++ b/hw/i386/pc_sysfw.c
> @@ -108,7 +108,7 @@ void pc_system_flash_create(PCMachineState *pcms)
>      }
>  }
>  
> -static void pc_system_flash_cleanup_unused(PCMachineState *pcms)
> +void pc_system_flash_cleanup_unused(PCMachineState *pcms)
>  {
>      char *prop_name;
>      int i;
> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> index e6135c34d6..497f2b7ab7 100644
> --- a/include/hw/i386/pc.h
> +++ b/include/hw/i386/pc.h
> @@ -187,6 +187,7 @@ int cmos_get_fd_drive_type(FloppyDriveType fd0);
>  
>  /* pc_sysfw.c */
>  void pc_system_flash_create(PCMachineState *pcms);
> +void pc_system_flash_cleanup_unused(PCMachineState *pcms);
>  void pc_system_firmware_init(PCMachineState *pcms, MemoryRegion *rom_memory);
>  
>  /* acpi-build.c */
>