From e6d0c3ce689585ad8f38c826e69ee04fb2c2257c Mon Sep 17 00:00:00 2001 From: Igor Mammedov Date: Mon, 9 Dec 2019 14:09:00 +0100 Subject: acpi: cpuhp: introduce 'Command data 2' field 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 Message-Id: <1575896942-331151-8-git-send-email-imammedo@redhat.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Reviewed-by: Laszlo Ersek --- hw/acpi/cpu.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'hw/acpi/cpu.c') 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; } -- cgit v1.2.3