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Re: [Qemu-devel] [PATCH] acpi-build: tweak acpi migration limits
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH] acpi-build: tweak acpi migration limits |
Date: |
Tue, 29 Jul 2014 10:25:56 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 |
Il 28/07/2014 23:15, Michael S. Tsirkin ha scritto:
> - Tweak error message for legacy machine type:
> Basically if table size exceeds the limits we set all
> bets are off for migration: e.g. it can start failing even
> within given qemu minor version simply because of a bugfix.
> - Increase table size to 128k.
> - Make sure we notice it long before we start getting close to the
> 128k limit: warn at 64k.
> - Don't fail if we exceed the limit: most people don't care about
> migration, even less people care about cross version miration.
>
> Signed-off-by: Michael S. Tsirkin <address@hidden>
> ---
> hw/i386/acpi-build.c | 16 +++++++++-------
> 1 file changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 2178894..816c6d9 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -62,7 +62,7 @@
> #define ACPI_BUILD_LEGACY_CPU_AML_SIZE 97
> #define ACPI_BUILD_ALIGN_SIZE 0x1000
>
> -#define ACPI_BUILD_TABLE_SIZE 0x10000
> +#define ACPI_BUILD_TABLE_SIZE 0x20000
>
> typedef struct AcpiCpuInfo {
> DECLARE_BITMAP(found_cpus, ACPI_CPU_HOTPLUG_ID_LIMIT);
> @@ -1586,17 +1586,19 @@ void acpi_build(PcGuestInfo *guest_info,
> AcpiBuildTables *tables)
> ACPI_BUILD_ALIGN_SIZE);
> if (tables->table_data->len > legacy_table_size) {
> /* Should happen only with PCI bridges and -M pc-i440fx-2.0. */
> - error_report("Warning: migration to QEMU 2.0 may not work.");
> + error_report("Warning: migration may not work.");
> }
> g_array_set_size(tables->table_data, legacy_table_size);
> } else {
> - if (tables->table_data->len > ACPI_BUILD_TABLE_SIZE) {
> + /* Make sure we have a buffer in case we need to resize the tables.
> */
> + if (tables->table_data->len > ACPI_BUILD_TABLE_SIZE / 2) {
> /* As of QEMU 2.1, this fires with 160 VCPUs and 255 memory
> slots. */
> - error_report("ACPI tables are larger than 64k. Please remove");
> - error_report("CPUs, NUMA nodes, memory slots or PCI bridges.");
> - exit(1);
> + error_report("Warning: ACPI tables are larger than 64k.");
> + error_report("Warning: migration may not work.");
> + error_report("Warning: please remove CPUs, NUMA nodes, "
> + "memory slots or PCI bridges.");
> }
> - g_array_set_size(tables->table_data, ACPI_BUILD_TABLE_SIZE);
> + acpi_align_size(tables->table_data, ACPI_BUILD_TABLE_SIZE);
> }
>
> acpi_align_size(tables->linker, ACPI_BUILD_ALIGN_SIZE);
>
Reviewed-by: Paolo Bonzini <address@hidden>