unsubscribe
________________________________
发件人: qemu-devel-bounces+liuping24=outlook....@nongnu.org
<qemu-devel-bounces+liuping24=outlook....@nongnu.org> 代表 Gavin Shan
<gs...@redhat.com>
发送时间: 2024年8月11日 21:59
收件人: Salil Mehta <salil.me...@huawei.com>; qemu-devel@nongnu.org
<qemu-devel@nongnu.org>; qemu-...@nongnu.org <qemu-...@nongnu.org>;
m...@redhat.com <m...@redhat.com>
抄送: m...@kernel.org <m...@kernel.org>; jean-phili...@linaro.org
<jean-phili...@linaro.org>; jonathan.came...@huawei.com
<jonathan.came...@huawei.com>; lpieral...@kernel.org <lpieral...@kernel.org>;
peter.mayd...@linaro.org <peter.mayd...@linaro.org>;
richard.hender...@linaro.org <richard.hender...@linaro.org>;
imamm...@redhat.com <imamm...@redhat.com>; andrew.jo...@linux.dev
<andrew.jo...@linux.dev>; da...@redhat.com <da...@redhat.com>;
phi...@linaro.org <phi...@linaro.org>; eric.au...@redhat.com
<eric.au...@redhat.com>; w...@kernel.org <w...@kernel.org>; a...@kernel.org
<a...@kernel.org>; oliver.up...@linux.dev <oliver.up...@linux.dev>;
pbonz...@redhat.com <pbonz...@redhat.com>; raf...@kernel.org
<raf...@kernel.org>; borntrae...@linux.ibm.com <borntrae...@linux.ibm.com>;
alex.ben...@linaro.org <alex.ben...@linaro.org>; npig...@gmail.com
<npig...@gmail.com>; hars...@linux.ibm.com <hars...@linux.ibm.com>;
li...@armlinux.org.uk <li...@armlinux.org.uk>; dar...@os.amperecomputing.com
<dar...@os.amperecomputing.com>; il...@os.amperecomputing.com
<il...@os.amperecomputing.com>; vis...@os.amperecomputing.com
<vis...@os.amperecomputing.com>; karl.heub...@oracle.com
<karl.heub...@oracle.com>; miguel.l...@oracle.com <miguel.l...@oracle.com>;
salil.me...@opnsrc.net <salil.me...@opnsrc.net>; zhukeqi...@huawei.com
<zhukeqi...@huawei.com>; wangxiongfe...@huawei.com <wangxiongfe...@huawei.com>;
wangyana...@huawei.com <wangyana...@huawei.com>; jiakern...@gmail.com
<jiakern...@gmail.com>; maob...@loongson.cn <maob...@loongson.cn>;
lixiang...@loongson.cn <lixiang...@loongson.cn>; shahu...@redhat.com
<shahu...@redhat.com>; zhao1....@intel.com <zhao1....@intel.com>;
linux...@huawei.com <linux...@huawei.com>
主题: Re: [PATCH RFC V3 02/29] cpu-common: Add common CPU utility for possible
vCPUs
On 6/14/24 9:36 AM, Salil Mehta wrote:
> This patch adds various utility functions that may be required to fetch or
> check
> the state of possible vCPUs. It also introduces the concept of *disabled*
> vCPUs,
> which are part of the *possible* vCPUs but are not enabled. This state will be
> used during machine initialization and later during the plugging or unplugging
> of vCPUs. We release the QOM CPU objects for all disabled vCPUs.
>
> Co-developed-by: Keqian Zhu <zhukeqi...@huawei.com>
> Signed-off-by: Keqian Zhu <zhukeqi...@huawei.com>
> Signed-off-by: Salil Mehta <salil.me...@huawei.com>
> ---
> cpu-common.c | 31 +++++++++++++++++++++++++
> include/hw/core/cpu.h | 54 +++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 85 insertions(+)
>
> diff --git a/cpu-common.c b/cpu-common.c
> index ce78273af5..49d2a50835 100644
> --- a/cpu-common.c
> +++ b/cpu-common.c
> @@ -24,6 +24,7 @@
> #include "sysemu/cpus.h"
> #include "qemu/lockable.h"
> #include "trace/trace-root.h"
> +#include "hw/boards.h"
>
> QemuMutex qemu_cpu_list_lock;
> static QemuCond exclusive_cond;
> @@ -107,6 +108,36 @@ void cpu_list_remove(CPUState *cpu)
> cpu_list_generation_id++;
> }
>
> +CPUState *qemu_get_possible_cpu(int index)
> +{
> + MachineState *ms = MACHINE(qdev_get_machine());
> + const CPUArchIdList *possible_cpus = ms->possible_cpus;
> +
> + assert((index >= 0) && (index < possible_cpus->len));
> +
> + return CPU(possible_cpus->cpus[index].cpu);
> +}
> +
> +bool qemu_present_cpu(CPUState *cpu)
> +{
> + return cpu;
> +}
> +
> +bool qemu_enabled_cpu(CPUState *cpu)
> +{
> + return cpu && !cpu->disabled;
> +}
> +
> +uint64_t qemu_get_cpu_archid(int cpu_index)
> +{
> + MachineState *ms = MACHINE(qdev_get_machine());
> + const CPUArchIdList *possible_cpus = ms->possible_cpus;
> +
> + assert((cpu_index >= 0) && (cpu_index < possible_cpus->len));
> +
> + return possible_cpus->cpus[cpu_index].arch_id;
> +}
> +
> CPUState *qemu_get_cpu(int index)
> {
> CPUState *cpu;
> diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
> index 60b160d0b4..60b4778da9 100644
> --- a/include/hw/core/cpu.h
> +++ b/include/hw/core/cpu.h
> @@ -528,6 +528,18 @@ struct CPUState {
> CPUPluginState *plugin_state;
> #endif
>
> + /*
> + * Some architectures do not allow the *presence* of vCPUs to be changed
> + * after the guest has booted, based on information specified by the
> + * VMM/firmware via ACPI MADT at boot time. Thus, to enable vCPU hotplug
> on
> + * these architectures, possible vCPUs can have a CPUState object in a
> + * 'disabled' state or may not have a CPUState object at all. This is
> + * possible when vCPU hotplug is supported, and vCPUs are
> + * 'yet-to-be-plugged' in the QOM or have been hot-unplugged. By default,
> + * every CPUState is enabled across all architectures.
> + */
> + bool disabled;
> +
The information to determine vCPU's state has been distributed to two data
structs:
MachineState::possible_cpus::cpus[] and CPUState. Why not just to maintain the
vCPU's
state from MachineState::possible_cpus::cpus[]? For example, adding a new
field, or
something similiar, to 'struct CPUArchId' as below.
typedef struct CPUArchId {
#define CPU_ARCH_ID_FLAG_PRESENT (1 << 0)
#define CPU_ARCH_ID_FLAG_ENABLED (1 << 1)
uint32_t flags;
:
} CPUArchId;
In order to determine if a CPUState instance is enabled or not.
CPUState::cpu_index
is used as the index to MachineState::possible_cpus::cpus[]. The flags can be
parsed
to determine the vCPU's state.
> /* TODO Move common fields from CPUArchState here. */
> int cpu_index;
> int cluster_index;
> @@ -914,6 +926,48 @@ static inline bool cpu_in_exclusive_context(const
> CPUState *cpu)
> */
> CPUState *qemu_get_cpu(int index);
>
> +/**
> + * qemu_get_possible_cpu:
> + * @index: The CPUState@cpu_index value of the CPU to obtain.
> + * Input index MUST be in range [0, Max Possible CPUs)
> + *
> + * If CPUState object exists,then it gets a CPU matching
> + * @index in the possible CPU array.
> + *
> + * Returns: The possible CPU or %NULL if CPU does not exist.
> + */
> +CPUState *qemu_get_possible_cpu(int index);
> +
> +/**
> + * qemu_present_cpu:
> + * @cpu: The vCPU to check
> + *
> + * Checks if the vCPU is amongst the present possible vcpus.
> + *
> + * Returns: True if it is present possible vCPU else false
> + */
> +bool qemu_present_cpu(CPUState *cpu);
> +
> +/**
> + * qemu_enabled_cpu:
> + * @cpu: The vCPU to check
> + *
> + * Checks if the vCPU is enabled.
> + *
> + * Returns: True if it is 'enabled' else false
> + */
> +bool qemu_enabled_cpu(CPUState *cpu);
> +
> +/**
> + * qemu_get_cpu_archid:
> + * @cpu_index: possible vCPU for which arch-id needs to be retreived
> + *
> + * Fetches the vCPU arch-id from the present possible vCPUs.
> + *
> + * Returns: arch-id of the possible vCPU
> + */
> +uint64_t qemu_get_cpu_archid(int cpu_index);
> +
> /**
> * cpu_exists:
> * @id: Guest-exposed CPU ID to lookup.
Thanks,
Gavin
