Re: [Qemu-devel] [PATCH 06/16] acpi: Save PCMachineState on AcpiBuildState

[Eduardo Habkost <ehabkost@redhat.com>]

On Mon, Dec 07, 2015 at 05:39:29PM +0200, Marcel Apfelbaum wrote:
> On 12/02/2015 03:47 AM, Eduardo Habkost wrote:
> >PCMachineState will be used in some of the steps of ACPI table
> >building.
> >
> >Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> >---
> >  hw/i386/acpi-build.c | 8 ++++----
> >  1 file changed, 4 insertions(+), 4 deletions(-)
> >
> >diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> >index 85a5c53..ca11c88 100644
> >--- a/hw/i386/acpi-build.c
> >+++ b/hw/i386/acpi-build.c
> >@@ -1644,7 +1644,7 @@ struct AcpiBuildState {
> >      MemoryRegion *table_mr;
> >      /* Is table patched? */
> >      uint8_t patched;
> >-    PcGuestInfo *guest_info;
> >+    PCMachineState *pcms;
> >      void *rsdp;
> >      MemoryRegion *rsdp_mr;
> >      MemoryRegion *linker_mr;
> >@@ -1855,7 +1855,7 @@ static void acpi_build_update(void *build_opaque, uint32_t offset)
> >
> >      acpi_build_tables_init(&tables);
> >
> >-    acpi_build(build_state->guest_info, &tables);
> >+    acpi_build(&build_state->pcms->acpi_guest_info, &tables);
> >
> >      acpi_ram_update(build_state->table_mr, tables.table_data);
> >
> >@@ -1916,12 +1916,12 @@ void acpi_setup(PCMachineState *pcms)
> >
> >      build_state = g_malloc0(sizeof *build_state);
> >
> >-    build_state->guest_info = guest_info;
> >+    build_state->pcms = pcms;
> 
> I am not "sold" on keeping a reference to machine in the build_state.
> We can always query current machine using qdev_machine() or something.
> 
> Keeping the "guest info" made sense since is used especially for ACPI,
> however the machine has a wider scope. (And not having to keep it
> around is a very good thing!)

I wouldn't mind using qdev_get_machine() if preferred by the
maintainer of that code, but I like to avoid it when possible. To
me, qdev_get_machine() is just a global variable disguised as a
harder-to-understand API.

-- 
Eduardo