On Fri, Sep 01, 2017 at 12:45:42PM -0300, Thadeu Lima de Souza Cascardo wrote:
Linux uses SRAT to determine the maximum memory in a system, which is
used to determine whether to use the swiotlb for IOMMU or not for a
device that supports only 32 bits of addresses.
Do you have a pointer to the corresponding Linux code, for
reference? Which SRAT entries Linux uses to make this decision?
When there is no NUMA configuration, qemu will not build SRAT. And when
memory hotplug is done, some Linux device drivers start failing.
Tested by running with -m 512M,slots=8,maxmem=1G, adding the memory,
putting that online and using the system. Without the patch, swiotlb is
not used and ATA driver fails. With the patch, swiotlb is used, no
driver failure is observed.
Signed-off-by: Thadeu Lima de Souza Cascardo <address@hidden>
As far as I can see, this will only add APIC entries and a memory
affinity entry for the first 640KB (which would be obviously
wrong) if pcms->numa_nodes is 0.
---
hw/i386/acpi-build.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 98dd424678..fb94249779 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -2645,6 +2645,9 @@ void acpi_build(AcpiBuildTables *tables, MachineState
*machine)
GArray *tables_blob = tables->table_data;
AcpiSlicOem slic_oem = { .id = NULL, .table_id = NULL };
Object *vmgenid_dev;
+ ram_addr_t hotplugabble_address_space_size =
+ object_property_get_int(OBJECT(pcms), PC_MACHINE_MEMHP_REGION_SIZE,
+ NULL);
acpi_get_pm_info(&pm);
acpi_get_misc_info(&misc);
@@ -2708,7 +2711,7 @@ void acpi_build(AcpiBuildTables *tables, MachineState
*machine)
build_tpm2(tables_blob, tables->linker);
}
}
- if (pcms->numa_nodes) {
+ if (pcms->numa_nodes || hotplugabble_address_space_size) {
acpi_add_table(table_offsets, tables_blob);
build_srat(tables_blob, tables->linker, machine);
if (have_numa_distance) {
--
2.11.0