On Wed, Aug 22, 2018 at 11:46:44AM +0200, Igor Mammedov wrote:
> Commit
> 10efd7e108 "pc: acpi: fix memory hotplug regression by reducing stub SRAT
> entry size"
> attemped to fix hotplug regression introduced by
> 848a1cc1e "hw/acpi-build: build SRAT memory affinity structures for DIMM
> devices"
>
> fixed issue for Windows/3.0+ linux kernels, however it regressed 2.6 based
> kernels (RHEL6) to the point where guest might crash at boot.
> Reason is that 2.6 kernel discards SRAT table due too small last entry
> which down the road leads to crashes. Hack I've tried in 10efd7e108 is also
> not ACPI spec compliant according to which whole possible RAM should be
> described in SRAT. Revert 10efd7e108 to fix regression for 2.6 based kernels.
>
> With 10efd7e108 reverted, I've also tried splitting SRAT table statically
> in different ways %/node and %/slot but Windows still fails to online
> 2nd pc-dimm hot-plugged into node 0 (as described in 10efd7e108) and
> sometimes even coldplugged pc-dimms where affected with static SRAT
> partitioning.
> The only known so far way where Windows stays happy is when we have 1
> SRAT entry in the last node covering all hotplug area.
>
> Revert 848a1cc1e until we come up with a way to avoid regression
> on Windows with hotplug area split in several entries.
> Tested this with 2.6/3.0 based kernels (RHEL6/7) and WS20[08/12/12R2/16]).
>
> Signed-off-by: Igor Mammedov <imamm...@redhat.com>
BTW should this cause any aml test blobs to change?
Does not seem to ...
> ---
> CC: haozhong.zh...@intel.com
> CC: m...@redhat.com
> CC: qemu-sta...@nongnu.org
> CC: ehabk...@redhat.com
> CC: ler...@redhat.com
> ---
> hw/i386/acpi-build.c | 73
> +++++++++-------------------------------------------
> 1 file changed, 12 insertions(+), 61 deletions(-)
>
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index e1ee8ae..1599caa 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -2251,64 +2251,6 @@ build_tpm2(GArray *table_data, BIOSLinker *linker,
> GArray *tcpalog)
> #define HOLE_640K_START (640 * KiB)
> #define HOLE_640K_END (1 * MiB)
>
> -static void build_srat_hotpluggable_memory(GArray *table_data, uint64_t base,
> - uint64_t len, int default_node)
> -{
> - MemoryDeviceInfoList *info_list = qmp_memory_device_list();
> - MemoryDeviceInfoList *info;
> - MemoryDeviceInfo *mi;
> - PCDIMMDeviceInfo *di;
> - uint64_t end = base + len, cur, size;
> - bool is_nvdimm;
> - AcpiSratMemoryAffinity *numamem;
> - MemoryAffinityFlags flags;
> -
> - for (cur = base, info = info_list;
> - cur < end;
> - cur += size, info = info->next) {
> - numamem = acpi_data_push(table_data, sizeof *numamem);
> -
> - if (!info) {
> - /*
> - * Entry is required for Windows to enable memory hotplug in OS
> - * and for Linux to enable SWIOTLB when booted with less than
> - * 4G of RAM. Windows works better if the entry sets proximity
> - * to the highest NUMA node in the machine at the end of the
> - * reserved space.
> - * Memory devices may override proximity set by this entry,
> - * providing _PXM method if necessary.
> - */
> - build_srat_memory(numamem, end - 1, 1, default_node,
> - MEM_AFFINITY_HOTPLUGGABLE |
> MEM_AFFINITY_ENABLED);
> - break;
> - }
> -
> - mi = info->value;
> - is_nvdimm = (mi->type == MEMORY_DEVICE_INFO_KIND_NVDIMM);
> - di = !is_nvdimm ? mi->u.dimm.data : mi->u.nvdimm.data;
> -
> - if (cur < di->addr) {
> - build_srat_memory(numamem, cur, di->addr - cur, default_node,
> - MEM_AFFINITY_HOTPLUGGABLE |
> MEM_AFFINITY_ENABLED);
> - numamem = acpi_data_push(table_data, sizeof *numamem);
> - }
> -
> - size = di->size;
> -
> - flags = MEM_AFFINITY_ENABLED;
> - if (di->hotpluggable) {
> - flags |= MEM_AFFINITY_HOTPLUGGABLE;
> - }
> - if (is_nvdimm) {
> - flags |= MEM_AFFINITY_NON_VOLATILE;
> - }
> -
> - build_srat_memory(numamem, di->addr, size, di->node, flags);
> - }
> -
> - qapi_free_MemoryDeviceInfoList(info_list);
> -}
> -
> static void
> build_srat(GArray *table_data, BIOSLinker *linker, MachineState *machine)
> {
> @@ -2414,10 +2356,19 @@ build_srat(GArray *table_data, BIOSLinker *linker,
> MachineState *machine)
> build_srat_memory(numamem, 0, 0, 0, MEM_AFFINITY_NOFLAGS);
> }
>
> + /*
> + * Entry is required for Windows to enable memory hotplug in OS
> + * and for Linux to enable SWIOTLB when booted with less than
> + * 4G of RAM. Windows works better if the entry sets proximity
> + * to the highest NUMA node in the machine.
> + * Memory devices may override proximity set by this entry,
> + * providing _PXM method if necessary.
> + */
> if (hotplugabble_address_space_size) {
> - build_srat_hotpluggable_memory(table_data,
> machine->device_memory->base,
> - hotplugabble_address_space_size,
> - pcms->numa_nodes - 1);
> + numamem = acpi_data_push(table_data, sizeof *numamem);
> + build_srat_memory(numamem, machine->device_memory->base,
> + hotplugabble_address_space_size, pcms->numa_nodes
> - 1,
> + MEM_AFFINITY_HOTPLUGGABLE | MEM_AFFINITY_ENABLED);
> }
>
> build_header(linker, table_data,
> --
> 2.7.4
