From: Igor Mammedov <imamm...@redhat.com>
No functional change in practice, patch only aims to properly
document (in spec and code) intended usage of the reserved space.
The new field is to be used for 2 purposes:
- detection of modern CPU hotplug interface using
CPHP_GET_NEXT_CPU_WITH_EVENT_CMD command.
procedure will be described in follow up patch:
"acpi: cpuhp: spec: add typical usecases"
- for returning upper 32 bits of architecture specific CPU ID,
for new CPHP_GET_CPU_ID_CMD command added by follow up patch:
"acpi: cpuhp: add CPHP_GET_CPU_ID_CMD command"
Change is backward compatible with 4.2 and older machines, as field was
unconditionally reserved and always returned 0x0 if modern CPU hotplug
interface was enabled.
Signed-off-by: Igor Mammedov <imamm...@redhat.com>
Message-Id: <1575896942-331151-8-git-send-email-imamm...@redhat.com>
Reviewed-by: Michael S. Tsirkin <m...@redhat.com>
Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
Reviewed-by: Laszlo Ersek <ler...@redhat.com>
---
docs/specs/acpi_cpu_hotplug.txt | 5 ++++-
hw/acpi/cpu.c | 11 +++++++++++
hw/acpi/trace-events | 1 +
3 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/docs/specs/acpi_cpu_hotplug.txt b/docs/specs/acpi_cpu_hotplug.txt
index 8fb9ad22e6..9879f9ef7e 100644
--- a/docs/specs/acpi_cpu_hotplug.txt
+++ b/docs/specs/acpi_cpu_hotplug.txt
@@ -44,7 +44,10 @@ keeps the current value.
read access:
offset:
- [0x0-0x3] reserved
+ [0x0-0x3] Command data 2: (DWORD access)
+ if value last stored in 'Command field':
+ 0: reads as 0x0
+ other values: reserved
[0x4] CPU device status fields: (1 byte access)
bits:
0: Device is enabled and may be used by guest
diff --git a/hw/acpi/cpu.c b/hw/acpi/cpu.c
index 87f30a31d7..d475c06953 100644
--- a/hw/acpi/cpu.c
+++ b/hw/acpi/cpu.c
@@ -12,6 +12,7 @@
#define ACPI_CPU_FLAGS_OFFSET_RW 4
#define ACPI_CPU_CMD_OFFSET_WR 5
#define ACPI_CPU_CMD_DATA_OFFSET_RW 8
+#define ACPI_CPU_CMD_DATA2_OFFSET_R 0
enum {
CPHP_GET_NEXT_CPU_WITH_EVENT_CMD = 0,
@@ -79,6 +80,16 @@ static uint64_t cpu_hotplug_rd(void *opaque, hwaddr addr,
unsigned size)
}
trace_cpuhp_acpi_read_cmd_data(cpu_st->selector, val);
break;
+ case ACPI_CPU_CMD_DATA2_OFFSET_R:
+ switch (cpu_st->command) {
+ case CPHP_GET_NEXT_CPU_WITH_EVENT_CMD:
+ val = 0;
+ break;
+ default:
+ break;
+ }
+ trace_cpuhp_acpi_read_cmd_data2(cpu_st->selector, val);
+ break;
default:
break;
}
diff --git a/hw/acpi/trace-events b/hw/acpi/trace-events
index 96b8273297..afbc77de1c 100644
--- a/hw/acpi/trace-events
+++ b/hw/acpi/trace-events
@@ -23,6 +23,7 @@ cpuhp_acpi_read_flags(uint32_t idx, uint8_t flags)
"idx[0x%"PRIx32"] flags: 0x%"
cpuhp_acpi_write_idx(uint32_t idx) "set active cpu idx: 0x%"PRIx32
cpuhp_acpi_write_cmd(uint32_t idx, uint8_t cmd) "idx[0x%"PRIx32"] cmd:
0x%"PRIx8
cpuhp_acpi_read_cmd_data(uint32_t idx, uint32_t data) "idx[0x%"PRIx32"] data:
0x%"PRIx32
+cpuhp_acpi_read_cmd_data2(uint32_t idx, uint32_t data) "idx[0x%"PRIx32"] data:
0x%"PRIx32
cpuhp_acpi_cpu_has_events(uint32_t idx, bool ins, bool rm) "idx[0x%"PRIx32"]
inserting: %d, removing: %d"
cpuhp_acpi_clear_inserting_evt(uint32_t idx) "idx[0x%"PRIx32"]"
cpuhp_acpi_clear_remove_evt(uint32_t idx) "idx[0x%"PRIx32"]"
--
MST
