diff mbox series

[RFC,v2,2/6] kvm: arm64: Add support for get_cur_cpufreq service

Message ID 20230331014356.1033759-3-davidai@google.com (mailing list archive)
State RFC, archived
Headers show
Series Improve VM CPUfreq and task placement behavior | expand

Commit Message

David Dai March 31, 2023, 1:43 a.m. UTC 
This service allows guests to query the host for frequency of the CPU
that the vCPU is currently running on.

Co-developed-by: Saravana Kannan <saravanak@google.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Signed-off-by: David Dai <davidai@google.com>
---
 Documentation/virt/kvm/api.rst                |  8 +++++++
 .../virt/kvm/arm/get_cur_cpufreq.rst          | 21 +++++++++++++++++++
 Documentation/virt/kvm/arm/index.rst          |  1 +
 arch/arm64/include/uapi/asm/kvm.h             |  1 +
 arch/arm64/kvm/arm.c                          |  1 +
 arch/arm64/kvm/hypercalls.c                   | 18 ++++++++++++++++
 include/linux/arm-smccc.h                     |  7 +++++++
 include/uapi/linux/kvm.h                      |  1 +
 tools/arch/arm64/include/uapi/asm/kvm.h       |  1 +
 9 files changed, 59 insertions(+)
 create mode 100644 Documentation/virt/kvm/arm/get_cur_cpufreq.rst

Comments

Bagas Sanjaya April 1, 2023, 3:12 a.m. UTC | #1 
On Thu, Mar 30, 2023 at 06:43:46PM -0700, David Dai wrote:
> diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
> index 62de0768d6aa..b0ff0ad700bf 100644
> --- a/Documentation/virt/kvm/api.rst
> +++ b/Documentation/virt/kvm/api.rst
> @@ -8380,6 +8380,14 @@ structure.
>  When getting the Modified Change Topology Report value, the attr->addr
>  must point to a byte where the value will be stored or retrieved from.
>  
> +8.40 KVM_CAP_GET_CUR_CPUFREQ
> +------------------------
> +
> +:Architectures: arm64
> +
> +This capability indicates that KVM supports getting the
> +frequency of the current CPU that the vCPU thread is running on.
> +
>  9. Known KVM API problems
>  =========================
>  
> diff --git a/Documentation/virt/kvm/arm/get_cur_cpufreq.rst b/Documentation/virt/kvm/arm/get_cur_cpufreq.rst
> new file mode 100644
> index 000000000000..06e0ed5b3868
> --- /dev/null
> +++ b/Documentation/virt/kvm/arm/get_cur_cpufreq.rst
> @@ -0,0 +1,21 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +get_cur_cpufreq support for arm/arm64
> +=============================
> +
> +Get_cur_cpufreq support is used to get current frequency(in KHz) of the
> +current CPU that the vCPU thread is running on.
> +
> +* ARM_SMCCC_VENDOR_HYP_KVM_GET_CUR_CPUFREQ_FUNC_ID: 0x86000040
> +
> +This hypercall uses the SMC32/HVC32 calling convention:
> +
> +ARM_SMCCC_VENDOR_HYP_KVM_GET_CUR_CPUFREQ_FUNC_ID
> +    ==============    ========    =====================================
> +    Function ID:      (uint32)    0x86000040
> +    Return Values:    (int32)     NOT_SUPPORTED(-1) on error, or
> +                      (uint32)    Frequency in KHz of current CPU that the
> +                                  vCPU thread is running on.
> +    Endianness:                   Must be the same endianness
> +                                  as the host.
> +    ==============    ========    =====================================

Sphinx reports htmldocs warnings:
/home/bagas/repo/linux-kernel/Documentation/virt/kvm/api.rst:8384: WARNING: Title underline too short.

8.40 KVM_CAP_GET_CUR_CPUFREQ
------------------------
/home/bagas/repo/linux-kernel/Documentation/virt/kvm/api.rst:8384: WARNING: Title underline too short.

8.40 KVM_CAP_GET_CUR_CPUFREQ
------------------------
/home/bagas/repo/linux-kernel/Documentation/virt/kvm/api.rst:8404: WARNING: Title underline too short.

I have applied the fixup:

---- >8 ----
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 8f905456e2b4a1..baf8a4c43b5839 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -8381,7 +8381,7 @@ When getting the Modified Change Topology Report value, the attr->addr
 must point to a byte where the value will be stored or retrieved from.
 
 8.40 KVM_CAP_GET_CUR_CPUFREQ
-------------------------
+----------------------------
 
 :Architectures: arm64
 
diff --git a/Documentation/virt/kvm/arm/get_cur_cpufreq.rst b/Documentation/virt/kvm/arm/get_cur_cpufreq.rst
index 06e0ed5b3868d7..76f112efb99f92 100644
--- a/Documentation/virt/kvm/arm/get_cur_cpufreq.rst
+++ b/Documentation/virt/kvm/arm/get_cur_cpufreq.rst
@@ -11,11 +11,12 @@ current CPU that the vCPU thread is running on.
 This hypercall uses the SMC32/HVC32 calling convention:
 
 ARM_SMCCC_VENDOR_HYP_KVM_GET_CUR_CPUFREQ_FUNC_ID
-    ==============    ========    =====================================
+
+    ==============    ========    ========================================
     Function ID:      (uint32)    0x86000040
     Return Values:    (int32)     NOT_SUPPORTED(-1) on error, or
                       (uint32)    Frequency in KHz of current CPU that the
                                   vCPU thread is running on.
     Endianness:                   Must be the same endianness
                                   as the host.
-    ==============    ========    =====================================
+    ==============    ========    ========================================

Thanks.
Bagas Sanjaya April 1, 2023, 3:16 a.m. UTC | #2 
On Thu, Mar 30, 2023 at 06:43:46PM -0700, David Dai wrote:
> +get_cur_cpufreq support for arm/arm64
> +=============================

Oops, I have to also fix this heading too:

---- >8 ----
diff --git a/Documentation/virt/kvm/arm/get_cur_cpufreq.rst b/Documentation/virt/kvm/arm/get_cur_cpufreq.rst
index 76f112efb99f92..21c2b2fe0c8acf 100644
--- a/Documentation/virt/kvm/arm/get_cur_cpufreq.rst
+++ b/Documentation/virt/kvm/arm/get_cur_cpufreq.rst
@@ -1,7 +1,7 @@
 .. SPDX-License-Identifier: GPL-2.0
 
 get_cur_cpufreq support for arm/arm64
-=============================
+=====================================
 
 Get_cur_cpufreq support is used to get current frequency(in KHz) of the
 current CPU that the vCPU thread is running on.

Thanks.
diff mbox series

Patch

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 62de0768d6aa..b0ff0ad700bf 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -8380,6 +8380,14 @@  structure.
 When getting the Modified Change Topology Report value, the attr->addr
 must point to a byte where the value will be stored or retrieved from.
 
+8.40 KVM_CAP_GET_CUR_CPUFREQ
+------------------------
+
+:Architectures: arm64
+
+This capability indicates that KVM supports getting the
+frequency of the current CPU that the vCPU thread is running on.
+
 9. Known KVM API problems
 =========================
 
diff --git a/Documentation/virt/kvm/arm/get_cur_cpufreq.rst b/Documentation/virt/kvm/arm/get_cur_cpufreq.rst
new file mode 100644
index 000000000000..06e0ed5b3868
--- /dev/null
+++ b/Documentation/virt/kvm/arm/get_cur_cpufreq.rst
@@ -0,0 +1,21 @@ 
+.. SPDX-License-Identifier: GPL-2.0
+
+get_cur_cpufreq support for arm/arm64
+=============================
+
+Get_cur_cpufreq support is used to get current frequency(in KHz) of the
+current CPU that the vCPU thread is running on.
+
+* ARM_SMCCC_VENDOR_HYP_KVM_GET_CUR_CPUFREQ_FUNC_ID: 0x86000040
+
+This hypercall uses the SMC32/HVC32 calling convention:
+
+ARM_SMCCC_VENDOR_HYP_KVM_GET_CUR_CPUFREQ_FUNC_ID
+    ==============    ========    =====================================
+    Function ID:      (uint32)    0x86000040
+    Return Values:    (int32)     NOT_SUPPORTED(-1) on error, or
+                      (uint32)    Frequency in KHz of current CPU that the
+                                  vCPU thread is running on.
+    Endianness:                   Must be the same endianness
+                                  as the host.
+    ==============    ========    =====================================
diff --git a/Documentation/virt/kvm/arm/index.rst b/Documentation/virt/kvm/arm/index.rst
index e84848432158..47afc5c1f24a 100644
--- a/Documentation/virt/kvm/arm/index.rst
+++ b/Documentation/virt/kvm/arm/index.rst
@@ -11,3 +11,4 @@  ARM
    hypercalls
    pvtime
    ptp_kvm
+   get_cur_cpufreq
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index f8129c624b07..ed8b63e91bdc 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -367,6 +367,7 @@  enum {
 enum {
 	KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT	= 0,
 	KVM_REG_ARM_VENDOR_HYP_BIT_PTP		= 1,
+	KVM_REG_ARM_VENDOR_HYP_BIT_GET_CUR_CPUFREQ	= 2,
 #ifdef __KERNEL__
 	KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_COUNT,
 #endif
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 3bd732eaf087..f960b136c611 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -220,6 +220,7 @@  int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_VCPU_ATTRIBUTES:
 	case KVM_CAP_PTP_KVM:
 	case KVM_CAP_ARM_SYSTEM_SUSPEND:
+	case KVM_CAP_GET_CUR_CPUFREQ:
 		r = 1;
 		break;
 	case KVM_CAP_SET_GUEST_DEBUG2:
diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c
index 5da884e11337..b3f4b90c024b 100644
--- a/arch/arm64/kvm/hypercalls.c
+++ b/arch/arm64/kvm/hypercalls.c
@@ -3,6 +3,9 @@ 
 
 #include <linux/arm-smccc.h>
 #include <linux/kvm_host.h>
+#include <linux/cpufreq.h>
+#include <linux/sched.h>
+#include <uapi/linux/sched/types.h>
 
 #include <asm/kvm_emulate.h>
 
@@ -16,6 +19,15 @@ 
 #define KVM_ARM_SMCCC_VENDOR_HYP_FEATURES			\
 	GENMASK(KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_COUNT - 1, 0)
 
+static void kvm_sched_get_cur_cpufreq(struct kvm_vcpu *vcpu, u64 *val)
+{
+	unsigned long ret_freq;
+
+	ret_freq = cpufreq_get(task_cpu(current));
+
+	val[0] = ret_freq;
+}
+
 static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val)
 {
 	struct system_time_snapshot systime_snapshot;
@@ -116,6 +128,9 @@  static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id)
 	case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
 		return test_bit(KVM_REG_ARM_VENDOR_HYP_BIT_PTP,
 				&smccc_feat->vendor_hyp_bmap);
+	case ARM_SMCCC_VENDOR_HYP_KVM_GET_CUR_CPUFREQ_FUNC_ID:
+		return test_bit(KVM_REG_ARM_VENDOR_HYP_BIT_GET_CUR_CPUFREQ,
+				&smccc_feat->vendor_hyp_bmap);
 	default:
 		return kvm_hvc_call_default_allowed(func_id);
 	}
@@ -213,6 +228,9 @@  int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
 	case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
 		kvm_ptp_get_time(vcpu, val);
 		break;
+	case ARM_SMCCC_VENDOR_HYP_KVM_GET_CUR_CPUFREQ_FUNC_ID:
+		kvm_sched_get_cur_cpufreq(vcpu, val);
+		break;
 	case ARM_SMCCC_TRNG_VERSION:
 	case ARM_SMCCC_TRNG_FEATURES:
 	case ARM_SMCCC_TRNG_GET_UUID:
diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
index 220c8c60e021..e15f1bdcf3f1 100644
--- a/include/linux/arm-smccc.h
+++ b/include/linux/arm-smccc.h
@@ -112,6 +112,7 @@ 
 /* KVM "vendor specific" services */
 #define ARM_SMCCC_KVM_FUNC_FEATURES		0
 #define ARM_SMCCC_KVM_FUNC_PTP			1
+#define ARM_SMCCC_KVM_FUNC_GET_CUR_CPUFREQ	64
 #define ARM_SMCCC_KVM_FUNC_FEATURES_2		127
 #define ARM_SMCCC_KVM_NUM_FUNCS			128
 
@@ -138,6 +139,12 @@ 
 #define KVM_PTP_VIRT_COUNTER			0
 #define KVM_PTP_PHYS_COUNTER			1
 
+#define ARM_SMCCC_VENDOR_HYP_KVM_GET_CUR_CPUFREQ_FUNC_ID		\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
+			   ARM_SMCCC_SMC_32,				\
+			   ARM_SMCCC_OWNER_VENDOR_HYP,			\
+			   ARM_SMCCC_KVM_FUNC_GET_CUR_CPUFREQ)
+
 /* Paravirtualised time calls (defined by ARM DEN0057A) */
 #define ARM_SMCCC_HV_PV_TIME_FEATURES				\
 	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,			\
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index d77aef872a0a..0a1a260243bf 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1184,6 +1184,7 @@  struct kvm_ppc_resize_hpt {
 #define KVM_CAP_S390_PROTECTED_ASYNC_DISABLE 224
 #define KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP 225
 #define KVM_CAP_PMU_EVENT_MASKED_EVENTS 226
+#define KVM_CAP_GET_CUR_CPUFREQ 512
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
diff --git a/tools/arch/arm64/include/uapi/asm/kvm.h b/tools/arch/arm64/include/uapi/asm/kvm.h
index f8129c624b07..ed8b63e91bdc 100644
--- a/tools/arch/arm64/include/uapi/asm/kvm.h
+++ b/tools/arch/arm64/include/uapi/asm/kvm.h
@@ -367,6 +367,7 @@  enum {
 enum {
 	KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT	= 0,
 	KVM_REG_ARM_VENDOR_HYP_BIT_PTP		= 1,
+	KVM_REG_ARM_VENDOR_HYP_BIT_GET_CUR_CPUFREQ	= 2,
 #ifdef __KERNEL__
 	KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_COUNT,
 #endif