diff mbox series

[4/5] LoongArch: Add paravirt interface for guest kernel

Message ID 20240103071615.3422264-5-maobibo@loongson.cn
State New
Headers
Series LoongArch: Add pv ipi support on LoongArch VM |

Commit Message

maobibo Jan. 3, 2024, 7:16 a.m. UTC 
  The patch add paravirt interface for guest kernel, it checks whether
system runs on VM mode. If it is, it will detect hypervisor type. And
returns true it is KVM hypervisor, else return false. Currently only
KVM hypervisor is supported, so there is only hypervisor detection
for KVM type.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
---
 arch/loongarch/Kconfig                        |  8 ++++
 arch/loongarch/include/asm/kvm_para.h         |  7 ++++
 arch/loongarch/include/asm/paravirt.h         | 27 ++++++++++++
 .../include/asm/paravirt_api_clock.h          |  1 +
 arch/loongarch/kernel/Makefile                |  1 +
 arch/loongarch/kernel/paravirt.c              | 41 +++++++++++++++++++
 arch/loongarch/kernel/setup.c                 |  2 +
 7 files changed, 87 insertions(+)
 create mode 100644 arch/loongarch/include/asm/paravirt.h
 create mode 100644 arch/loongarch/include/asm/paravirt_api_clock.h
 create mode 100644 arch/loongarch/kernel/paravirt.c

Comments

Juergen Gross Jan. 3, 2024, 7:40 a.m. UTC | #1 
On 03.01.24 08:16, Bibo Mao wrote:
> The patch add paravirt interface for guest kernel, it checks whether
> system runs on VM mode. If it is, it will detect hypervisor type. And
> returns true it is KVM hypervisor, else return false. Currently only
> KVM hypervisor is supported, so there is only hypervisor detection
> for KVM type.

I guess you are talking of pv_guest_init() here? Or do you mean
kvm_para_available()?

> 
> Signed-off-by: Bibo Mao <maobibo@loongson.cn>
> ---
>   arch/loongarch/Kconfig                        |  8 ++++
>   arch/loongarch/include/asm/kvm_para.h         |  7 ++++
>   arch/loongarch/include/asm/paravirt.h         | 27 ++++++++++++
>   .../include/asm/paravirt_api_clock.h          |  1 +
>   arch/loongarch/kernel/Makefile                |  1 +
>   arch/loongarch/kernel/paravirt.c              | 41 +++++++++++++++++++
>   arch/loongarch/kernel/setup.c                 |  2 +
>   7 files changed, 87 insertions(+)
>   create mode 100644 arch/loongarch/include/asm/paravirt.h
>   create mode 100644 arch/loongarch/include/asm/paravirt_api_clock.h
>   create mode 100644 arch/loongarch/kernel/paravirt.c
> 
> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> index ee123820a476..940e5960d297 100644
> --- a/arch/loongarch/Kconfig
> +++ b/arch/loongarch/Kconfig
> @@ -564,6 +564,14 @@ config CPU_HAS_PREFETCH
>   	bool
>   	default y
>   
> +config PARAVIRT
> +	bool "Enable paravirtualization code"
> +	help
> +          This changes the kernel so it can modify itself when it is run
> +	  under a hypervisor, potentially improving performance significantly
> +	  over full virtualization.  However, when run without a hypervisor
> +	  the kernel is theoretically slower and slightly larger.
> +
>   config ARCH_SUPPORTS_KEXEC
>   	def_bool y
>   
> diff --git a/arch/loongarch/include/asm/kvm_para.h b/arch/loongarch/include/asm/kvm_para.h
> index 9425d3b7e486..41200e922a82 100644
> --- a/arch/loongarch/include/asm/kvm_para.h
> +++ b/arch/loongarch/include/asm/kvm_para.h
> @@ -2,6 +2,13 @@
>   #ifndef _ASM_LOONGARCH_KVM_PARA_H
>   #define _ASM_LOONGARCH_KVM_PARA_H
>   
> +/*
> + * Hypcall code field
> + */
> +#define HYPERVISOR_KVM			1
> +#define HYPERVISOR_VENDOR_SHIFT		8
> +#define HYPERCALL_CODE(vendor, code)	((vendor << HYPERVISOR_VENDOR_SHIFT) + code)
> +
>   /*
>    * LoongArch hypcall return code
>    */
> diff --git a/arch/loongarch/include/asm/paravirt.h b/arch/loongarch/include/asm/paravirt.h
> new file mode 100644
> index 000000000000..b64813592ba0
> --- /dev/null
> +++ b/arch/loongarch/include/asm/paravirt.h
> @@ -0,0 +1,27 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_LOONGARCH_PARAVIRT_H
> +#define _ASM_LOONGARCH_PARAVIRT_H
> +
> +#ifdef CONFIG_PARAVIRT
> +#include <linux/static_call_types.h>
> +struct static_key;
> +extern struct static_key paravirt_steal_enabled;
> +extern struct static_key paravirt_steal_rq_enabled;
> +
> +u64 dummy_steal_clock(int cpu);
> +DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);
> +
> +static inline u64 paravirt_steal_clock(int cpu)
> +{
> +	return static_call(pv_steal_clock)(cpu);
> +}
> +
> +int pv_guest_init(void);
> +#else
> +static inline int pv_guest_init(void)
> +{
> +	return 0;
> +}
> +
> +#endif // CONFIG_PARAVIRT
> +#endif
> diff --git a/arch/loongarch/include/asm/paravirt_api_clock.h b/arch/loongarch/include/asm/paravirt_api_clock.h
> new file mode 100644
> index 000000000000..65ac7cee0dad
> --- /dev/null
> +++ b/arch/loongarch/include/asm/paravirt_api_clock.h
> @@ -0,0 +1 @@
> +#include <asm/paravirt.h>
> diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
> index 3c808c680370..662e6e9de12d 100644
> --- a/arch/loongarch/kernel/Makefile
> +++ b/arch/loongarch/kernel/Makefile
> @@ -48,6 +48,7 @@ obj-$(CONFIG_MODULES)		+= module.o module-sections.o
>   obj-$(CONFIG_STACKTRACE)	+= stacktrace.o
>   
>   obj-$(CONFIG_PROC_FS)		+= proc.o
> +obj-$(CONFIG_PARAVIRT)		+= paravirt.o
>   
>   obj-$(CONFIG_SMP)		+= smp.o
>   
> diff --git a/arch/loongarch/kernel/paravirt.c b/arch/loongarch/kernel/paravirt.c
> new file mode 100644
> index 000000000000..21d01d05791a
> --- /dev/null
> +++ b/arch/loongarch/kernel/paravirt.c
> @@ -0,0 +1,41 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <linux/export.h>
> +#include <linux/types.h>
> +#include <linux/jump_label.h>
> +#include <linux/kvm_para.h>
> +#include <asm/paravirt.h>
> +#include <linux/static_call.h>
> +
> +struct static_key paravirt_steal_enabled;
> +struct static_key paravirt_steal_rq_enabled;
> +
> +static u64 native_steal_clock(int cpu)
> +{
> +	return 0;
> +}
> +
> +DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock);

This is the 4th arch with the same definition of native_steal_clock() and
pv_steal_clock. I think we should add a common file kernel/paravirt.c and
move the related functions from the archs into the new file.

If you don't want to do that I can prepare a series.

> +
> +static bool kvm_para_available(void)
> +{
> +	static int hypervisor_type;
> +	int config;
> +
> +	if (!hypervisor_type) {
> +		config = read_cpucfg(CPUCFG_KVM_SIG);
> +		if (!memcmp(&config, KVM_SIGNATURE, 4))
> +			hypervisor_type = HYPERVISOR_KVM;
> +	}
> +
> +	return hypervisor_type == HYPERVISOR_KVM;
> +}
> +
> +int __init pv_guest_init(void)
> +{
> +	if (!cpu_has_hypervisor)
> +		return 0;
> +	if (!kvm_para_available())
> +		return 0;
> +
> +	return 1;
> +}
> diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
> index d183a745fb85..fa680bdd0bd1 100644
> --- a/arch/loongarch/kernel/setup.c
> +++ b/arch/loongarch/kernel/setup.c
> @@ -43,6 +43,7 @@
>   #include <asm/efi.h>
>   #include <asm/loongson.h>
>   #include <asm/numa.h>
> +#include <asm/paravirt.h>
>   #include <asm/pgalloc.h>
>   #include <asm/sections.h>
>   #include <asm/setup.h>
> @@ -376,6 +377,7 @@ void __init platform_init(void)
>   	pr_info("The BIOS Version: %s\n", b_info.bios_version);
>   
>   	efi_runtime_init();
> +	pv_guest_init();

Any reason pv_guest_init() needs to return a value at all, seeing that you don't
use the returned value?


Juergen
maobibo Jan. 3, 2024, 8 a.m. UTC | #2 
On 2024/1/3 下午3:40, Jürgen Groß wrote:
> On 03.01.24 08:16, Bibo Mao wrote:
>> The patch add paravirt interface for guest kernel, it checks whether
>> system runs on VM mode. If it is, it will detect hypervisor type. And
>> returns true it is KVM hypervisor, else return false. Currently only
>> KVM hypervisor is supported, so there is only hypervisor detection
>> for KVM type.
> 
> I guess you are talking of pv_guest_init() here? Or do you mean
> kvm_para_available()?
yes, it is pv_guest_init. It will be better if all hypervisor detection
is called in function pv_guest_init. Currently there is only kvm 
hypervisor, kvm_para_available is hard-coded in pv_guest_init here.

I can split file paravirt.c into paravirt.c and kvm.c, paravirt.c is 
used for hypervisor detection, and move code relative with pv_ipi into kvm.c

Regards
Bibo Mao
> 
>>
>> Signed-off-by: Bibo Mao <maobibo@loongson.cn>
>> ---
>>   arch/loongarch/Kconfig                        |  8 ++++
>>   arch/loongarch/include/asm/kvm_para.h         |  7 ++++
>>   arch/loongarch/include/asm/paravirt.h         | 27 ++++++++++++
>>   .../include/asm/paravirt_api_clock.h          |  1 +
>>   arch/loongarch/kernel/Makefile                |  1 +
>>   arch/loongarch/kernel/paravirt.c              | 41 +++++++++++++++++++
>>   arch/loongarch/kernel/setup.c                 |  2 +
>>   7 files changed, 87 insertions(+)
>>   create mode 100644 arch/loongarch/include/asm/paravirt.h
>>   create mode 100644 arch/loongarch/include/asm/paravirt_api_clock.h
>>   create mode 100644 arch/loongarch/kernel/paravirt.c
>>
>> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
>> index ee123820a476..940e5960d297 100644
>> --- a/arch/loongarch/Kconfig
>> +++ b/arch/loongarch/Kconfig
>> @@ -564,6 +564,14 @@ config CPU_HAS_PREFETCH
>>       bool
>>       default y
>> +config PARAVIRT
>> +    bool "Enable paravirtualization code"
>> +    help
>> +          This changes the kernel so it can modify itself when it is run
>> +      under a hypervisor, potentially improving performance 
>> significantly
>> +      over full virtualization.  However, when run without a hypervisor
>> +      the kernel is theoretically slower and slightly larger.
>> +
>>   config ARCH_SUPPORTS_KEXEC
>>       def_bool y
>> diff --git a/arch/loongarch/include/asm/kvm_para.h 
>> b/arch/loongarch/include/asm/kvm_para.h
>> index 9425d3b7e486..41200e922a82 100644
>> --- a/arch/loongarch/include/asm/kvm_para.h
>> +++ b/arch/loongarch/include/asm/kvm_para.h
>> @@ -2,6 +2,13 @@
>>   #ifndef _ASM_LOONGARCH_KVM_PARA_H
>>   #define _ASM_LOONGARCH_KVM_PARA_H
>> +/*
>> + * Hypcall code field
>> + */
>> +#define HYPERVISOR_KVM            1
>> +#define HYPERVISOR_VENDOR_SHIFT        8
>> +#define HYPERCALL_CODE(vendor, code)    ((vendor << 
>> HYPERVISOR_VENDOR_SHIFT) + code)
>> +
>>   /*
>>    * LoongArch hypcall return code
>>    */
>> diff --git a/arch/loongarch/include/asm/paravirt.h 
>> b/arch/loongarch/include/asm/paravirt.h
>> new file mode 100644
>> index 000000000000..b64813592ba0
>> --- /dev/null
>> +++ b/arch/loongarch/include/asm/paravirt.h
>> @@ -0,0 +1,27 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +#ifndef _ASM_LOONGARCH_PARAVIRT_H
>> +#define _ASM_LOONGARCH_PARAVIRT_H
>> +
>> +#ifdef CONFIG_PARAVIRT
>> +#include <linux/static_call_types.h>
>> +struct static_key;
>> +extern struct static_key paravirt_steal_enabled;
>> +extern struct static_key paravirt_steal_rq_enabled;
>> +
>> +u64 dummy_steal_clock(int cpu);
>> +DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);
>> +
>> +static inline u64 paravirt_steal_clock(int cpu)
>> +{
>> +    return static_call(pv_steal_clock)(cpu);
>> +}
>> +
>> +int pv_guest_init(void);
>> +#else
>> +static inline int pv_guest_init(void)
>> +{
>> +    return 0;
>> +}
>> +
>> +#endif // CONFIG_PARAVIRT
>> +#endif
>> diff --git a/arch/loongarch/include/asm/paravirt_api_clock.h 
>> b/arch/loongarch/include/asm/paravirt_api_clock.h
>> new file mode 100644
>> index 000000000000..65ac7cee0dad
>> --- /dev/null
>> +++ b/arch/loongarch/include/asm/paravirt_api_clock.h
>> @@ -0,0 +1 @@
>> +#include <asm/paravirt.h>
>> diff --git a/arch/loongarch/kernel/Makefile 
>> b/arch/loongarch/kernel/Makefile
>> index 3c808c680370..662e6e9de12d 100644
>> --- a/arch/loongarch/kernel/Makefile
>> +++ b/arch/loongarch/kernel/Makefile
>> @@ -48,6 +48,7 @@ obj-$(CONFIG_MODULES)        += module.o 
>> module-sections.o
>>   obj-$(CONFIG_STACKTRACE)    += stacktrace.o
>>   obj-$(CONFIG_PROC_FS)        += proc.o
>> +obj-$(CONFIG_PARAVIRT)        += paravirt.o
>>   obj-$(CONFIG_SMP)        += smp.o
>> diff --git a/arch/loongarch/kernel/paravirt.c 
>> b/arch/loongarch/kernel/paravirt.c
>> new file mode 100644
>> index 000000000000..21d01d05791a
>> --- /dev/null
>> +++ b/arch/loongarch/kernel/paravirt.c
>> @@ -0,0 +1,41 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +#include <linux/export.h>
>> +#include <linux/types.h>
>> +#include <linux/jump_label.h>
>> +#include <linux/kvm_para.h>
>> +#include <asm/paravirt.h>
>> +#include <linux/static_call.h>
>> +
>> +struct static_key paravirt_steal_enabled;
>> +struct static_key paravirt_steal_rq_enabled;
>> +
>> +static u64 native_steal_clock(int cpu)
>> +{
>> +    return 0;
>> +}
>> +
>> +DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock);
> 
> This is the 4th arch with the same definition of native_steal_clock() and
> pv_steal_clock. I think we should add a common file kernel/paravirt.c and
> move the related functions from the archs into the new file.
> 
> If you don't want to do that I can prepare a series.
> 
>> +
>> +static bool kvm_para_available(void)
>> +{
>> +    static int hypervisor_type;
>> +    int config;
>> +
>> +    if (!hypervisor_type) {
>> +        config = read_cpucfg(CPUCFG_KVM_SIG);
>> +        if (!memcmp(&config, KVM_SIGNATURE, 4))
>> +            hypervisor_type = HYPERVISOR_KVM;
>> +    }
>> +
>> +    return hypervisor_type == HYPERVISOR_KVM;
>> +}
>> +
>> +int __init pv_guest_init(void)
>> +{
>> +    if (!cpu_has_hypervisor)
>> +        return 0;
>> +    if (!kvm_para_available())
>> +        return 0;
>> +
>> +    return 1;
>> +}
>> diff --git a/arch/loongarch/kernel/setup.c 
>> b/arch/loongarch/kernel/setup.c
>> index d183a745fb85..fa680bdd0bd1 100644
>> --- a/arch/loongarch/kernel/setup.c
>> +++ b/arch/loongarch/kernel/setup.c
>> @@ -43,6 +43,7 @@
>>   #include <asm/efi.h>
>>   #include <asm/loongson.h>
>>   #include <asm/numa.h>
>> +#include <asm/paravirt.h>
>>   #include <asm/pgalloc.h>
>>   #include <asm/sections.h>
>>   #include <asm/setup.h>
>> @@ -376,6 +377,7 @@ void __init platform_init(void)
>>       pr_info("The BIOS Version: %s\n", b_info.bios_version);
>>       efi_runtime_init();
>> +    pv_guest_init();
> 
> Any reason pv_guest_init() needs to return a value at all, seeing that 
> you don't
> use the returned value?
> 
> 
> Juergen
Juergen Gross Jan. 3, 2024, 8:14 a.m. UTC | #3 
On 03.01.24 09:00, maobibo wrote:
> 
> 
> On 2024/1/3 下午3:40, Jürgen Groß wrote:
>> On 03.01.24 08:16, Bibo Mao wrote:
>>> The patch add paravirt interface for guest kernel, it checks whether
>>> system runs on VM mode. If it is, it will detect hypervisor type. And
>>> returns true it is KVM hypervisor, else return false. Currently only
>>> KVM hypervisor is supported, so there is only hypervisor detection
>>> for KVM type.
>>
>> I guess you are talking of pv_guest_init() here? Or do you mean
>> kvm_para_available()?
> yes, it is pv_guest_init. It will be better if all hypervisor detection
> is called in function pv_guest_init. Currently there is only kvm hypervisor, 
> kvm_para_available is hard-coded in pv_guest_init here.

I think this is no problem as long as there are not more hypervisors
supported.

> 
> I can split file paravirt.c into paravirt.c and kvm.c, paravirt.c is used for 
> hypervisor detection, and move code relative with pv_ipi into kvm.c

I wouldn't do that right now.

Just be a little bit more specific in the commit message (use the related
function name instead of "it").


Juergen
maobibo Jan. 3, 2024, 8:54 a.m. UTC | #4 
On 2024/1/3 下午4:14, Juergen Gross wrote:
> On 03.01.24 09:00, maobibo wrote:
>>
>>
>> On 2024/1/3 下午3:40, Jürgen Groß wrote:
>>> On 03.01.24 08:16, Bibo Mao wrote:
>>>> The patch add paravirt interface for guest kernel, it checks whether
>>>> system runs on VM mode. If it is, it will detect hypervisor type. And
>>>> returns true it is KVM hypervisor, else return false. Currently only
>>>> KVM hypervisor is supported, so there is only hypervisor detection
>>>> for KVM type.
>>>
>>> I guess you are talking of pv_guest_init() here? Or do you mean
>>> kvm_para_available()?
>> yes, it is pv_guest_init. It will be better if all hypervisor detection
>> is called in function pv_guest_init. Currently there is only kvm 
>> hypervisor, kvm_para_available is hard-coded in pv_guest_init here.
> 
> I think this is no problem as long as there are not more hypervisors
> supported.
> 
>>
>> I can split file paravirt.c into paravirt.c and kvm.c, paravirt.c is 
>> used for hypervisor detection, and move code relative with pv_ipi into 
>> kvm.c
> 
> I wouldn't do that right now.
> 
> Just be a little bit more specific in the commit message (use the related
> function name instead of "it").
Sure, will do this in next version, and thanks for your guidance.

Regards
Bibo Mao
> 
> 
> Juergen
diff mbox series

Patch

diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index ee123820a476..940e5960d297 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -564,6 +564,14 @@  config CPU_HAS_PREFETCH
 	bool
 	default y
 
+config PARAVIRT
+	bool "Enable paravirtualization code"
+	help
+          This changes the kernel so it can modify itself when it is run
+	  under a hypervisor, potentially improving performance significantly
+	  over full virtualization.  However, when run without a hypervisor
+	  the kernel is theoretically slower and slightly larger.
+
 config ARCH_SUPPORTS_KEXEC
 	def_bool y
 
diff --git a/arch/loongarch/include/asm/kvm_para.h b/arch/loongarch/include/asm/kvm_para.h
index 9425d3b7e486..41200e922a82 100644
--- a/arch/loongarch/include/asm/kvm_para.h
+++ b/arch/loongarch/include/asm/kvm_para.h
@@ -2,6 +2,13 @@ 
 #ifndef _ASM_LOONGARCH_KVM_PARA_H
 #define _ASM_LOONGARCH_KVM_PARA_H
 
+/*
+ * Hypcall code field
+ */
+#define HYPERVISOR_KVM			1
+#define HYPERVISOR_VENDOR_SHIFT		8
+#define HYPERCALL_CODE(vendor, code)	((vendor << HYPERVISOR_VENDOR_SHIFT) + code)
+
 /*
  * LoongArch hypcall return code
  */
diff --git a/arch/loongarch/include/asm/paravirt.h b/arch/loongarch/include/asm/paravirt.h
new file mode 100644
index 000000000000..b64813592ba0
--- /dev/null
+++ b/arch/loongarch/include/asm/paravirt.h
@@ -0,0 +1,27 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_LOONGARCH_PARAVIRT_H
+#define _ASM_LOONGARCH_PARAVIRT_H
+
+#ifdef CONFIG_PARAVIRT
+#include <linux/static_call_types.h>
+struct static_key;
+extern struct static_key paravirt_steal_enabled;
+extern struct static_key paravirt_steal_rq_enabled;
+
+u64 dummy_steal_clock(int cpu);
+DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);
+
+static inline u64 paravirt_steal_clock(int cpu)
+{
+	return static_call(pv_steal_clock)(cpu);
+}
+
+int pv_guest_init(void);
+#else
+static inline int pv_guest_init(void)
+{
+	return 0;
+}
+
+#endif // CONFIG_PARAVIRT
+#endif
diff --git a/arch/loongarch/include/asm/paravirt_api_clock.h b/arch/loongarch/include/asm/paravirt_api_clock.h
new file mode 100644
index 000000000000..65ac7cee0dad
--- /dev/null
+++ b/arch/loongarch/include/asm/paravirt_api_clock.h
@@ -0,0 +1 @@ 
+#include <asm/paravirt.h>
diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
index 3c808c680370..662e6e9de12d 100644
--- a/arch/loongarch/kernel/Makefile
+++ b/arch/loongarch/kernel/Makefile
@@ -48,6 +48,7 @@  obj-$(CONFIG_MODULES)		+= module.o module-sections.o
 obj-$(CONFIG_STACKTRACE)	+= stacktrace.o
 
 obj-$(CONFIG_PROC_FS)		+= proc.o
+obj-$(CONFIG_PARAVIRT)		+= paravirt.o
 
 obj-$(CONFIG_SMP)		+= smp.o
 
diff --git a/arch/loongarch/kernel/paravirt.c b/arch/loongarch/kernel/paravirt.c
new file mode 100644
index 000000000000..21d01d05791a
--- /dev/null
+++ b/arch/loongarch/kernel/paravirt.c
@@ -0,0 +1,41 @@ 
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/export.h>
+#include <linux/types.h>
+#include <linux/jump_label.h>
+#include <linux/kvm_para.h>
+#include <asm/paravirt.h>
+#include <linux/static_call.h>
+
+struct static_key paravirt_steal_enabled;
+struct static_key paravirt_steal_rq_enabled;
+
+static u64 native_steal_clock(int cpu)
+{
+	return 0;
+}
+
+DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock);
+
+static bool kvm_para_available(void)
+{
+	static int hypervisor_type;
+	int config;
+
+	if (!hypervisor_type) {
+		config = read_cpucfg(CPUCFG_KVM_SIG);
+		if (!memcmp(&config, KVM_SIGNATURE, 4))
+			hypervisor_type = HYPERVISOR_KVM;
+	}
+
+	return hypervisor_type == HYPERVISOR_KVM;
+}
+
+int __init pv_guest_init(void)
+{
+	if (!cpu_has_hypervisor)
+		return 0;
+	if (!kvm_para_available())
+		return 0;
+
+	return 1;
+}
diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
index d183a745fb85..fa680bdd0bd1 100644
--- a/arch/loongarch/kernel/setup.c
+++ b/arch/loongarch/kernel/setup.c
@@ -43,6 +43,7 @@ 
 #include <asm/efi.h>
 #include <asm/loongson.h>
 #include <asm/numa.h>
+#include <asm/paravirt.h>
 #include <asm/pgalloc.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
@@ -376,6 +377,7 @@  void __init platform_init(void)
 	pr_info("The BIOS Version: %s\n", b_info.bios_version);
 
 	efi_runtime_init();
+	pv_guest_init();
 }
 
 static void __init check_kernel_sections_mem(void)