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 1.4.1 From 3a61c8db9d25ff8ed08c5f96acecd63707187904 Mon Sep 17 00:00:00 2001 From: Igor Mammedov Date: Mon, 9 Dec 2019 14:09:02 +0100 Subject: acpi: cpuhp: add CPHP_GET_CPU_ID_CMD command Firmware can enumerate present at boot APs by broadcasting wakeup IPI, so that woken up secondary CPUs could register them-selves. However in CPU hotplug case, it would need to know architecture specific CPU IDs for possible and hotplugged CPUs so it could prepare environment for and wake hotplugged AP. Reuse and extend existing CPU hotplug interface to return architecture specific ID for currently selected CPU in 2 registers: - lower 32 bits in ACPI_CPU_CMD_DATA_OFFSET_RW - upper 32 bits in ACPI_CPU_CMD_DATA2_OFFSET_R On x86, firmware will use CPHP_GET_CPU_ID_CMD for fetching the APIC ID when handling hotplug SMI. Later, CPHP_GET_CPU_ID_CMD will be used on ARM to retrieve MPIDR, which serves the similar to APIC ID purpose. Signed-off-by: Igor Mammedov Message-Id: <1575896942-331151-10-git-send-email-imammedo@redhat.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Reviewed-by: Laszlo Ersek --- docs/specs/acpi_cpu_hotplug.txt | 3 +++ hw/acpi/cpu.c | 7 +++++++ 2 files changed, 10 insertions(+) (limited to 'hw/acpi/cpu.c') diff --git a/docs/specs/acpi_cpu_hotplug.txt b/docs/specs/acpi_cpu_hotplug.txt index cb99cf3c8e..a8ce5e7402 100644 --- a/docs/specs/acpi_cpu_hotplug.txt +++ b/docs/specs/acpi_cpu_hotplug.txt @@ -47,6 +47,7 @@ read access: [0x0-0x3] Command data 2: (DWORD access) if value last stored in 'Command field': 0: reads as 0x0 + 3: upper 32 bits of architecture specific CPU ID value other values: reserved [0x4] CPU device status fields: (1 byte access) bits: @@ -61,6 +62,8 @@ read access: [0x8] Command data: (DWORD access) contains 0 unless value last stored in 'Command field' is one of: 0: contains 'CPU selector' value of a CPU with pending event[s] + 3: lower 32 bits of architecture specific CPU ID value + (in x86 case: APIC ID) write access: offset: diff --git a/hw/acpi/cpu.c b/hw/acpi/cpu.c index d475c06953..e2c957ce00 100644 --- a/hw/acpi/cpu.c +++ b/hw/acpi/cpu.c @@ -18,6 +18,7 @@ enum { CPHP_GET_NEXT_CPU_WITH_EVENT_CMD = 0, CPHP_OST_EVENT_CMD = 1, CPHP_OST_STATUS_CMD = 2, + CPHP_GET_CPU_ID_CMD = 3, CPHP_CMD_MAX }; @@ -75,6 +76,9 @@ static uint64_t cpu_hotplug_rd(void *opaque, hwaddr addr, unsigned size) case CPHP_GET_NEXT_CPU_WITH_EVENT_CMD: val = cpu_st->selector; break; + case CPHP_GET_CPU_ID_CMD: + val = cdev->arch_id & 0xFFFFFFFF; + break; default: break; } @@ -85,6 +89,9 @@ static uint64_t cpu_hotplug_rd(void *opaque, hwaddr addr, unsigned size) case CPHP_GET_NEXT_CPU_WITH_EVENT_CMD: val = 0; break; + case CPHP_GET_CPU_ID_CMD: + val = cdev->arch_id >> 32; + break; default: break; } -- cgit 1.4.1