[patch 0/2] qemu support for kvm cpu freq hypercalls

[patch 0/2] qemu support for kvm cpu freq hypercalls

[Marcelo Tosatti]

Add a new cpu flag to allow vCPUs to perform frequency change
hypercalls from userspace.

See the kernel patchseries for more details.

[patch 1/2] kvm: sync linux headers

[Marcelo Tosatti]

[-- Attachment #1: sync-linux-headers --]
[-- Type: text/plain, Size: 3411 bytes --]

Sync linux headers.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

---
 linux-headers/asm-x86/kvm.h      |    5 +++++
 linux-headers/asm-x86/kvm_para.h |   13 ++++++++++++-
 linux-headers/linux/kvm.h        |    8 ++++++--
 linux-headers/linux/kvm_para.h   |    7 +++++++
 4 files changed, 30 insertions(+), 3 deletions(-)

Index: qemu/linux-headers/asm-x86/kvm.h
===================================================================
--- qemu.orig/linux-headers/asm-x86/kvm.h	2016-12-29 15:45:22.415325241 -0200
+++ qemu/linux-headers/asm-x86/kvm.h	2017-01-31 09:47:45.740645314 -0200
@@ -357,4 +357,9 @@
 #define KVM_X86_QUIRK_LINT0_REENABLED	(1 << 0)
 #define KVM_X86_QUIRK_CD_NW_CLEARED	(1 << 1)
 
+struct kvm_vcpu_allow_freq {
+	__u16 enable;
+	__u16 pad[7];
+};
+
 #endif /* _ASM_X86_KVM_H */
Index: qemu/linux-headers/asm-x86/kvm_para.h
===================================================================
--- qemu.orig/linux-headers/asm-x86/kvm_para.h	2016-12-29 15:44:51.281263648 -0200
+++ qemu/linux-headers/asm-x86/kvm_para.h	2017-01-31 09:47:45.740645314 -0200
@@ -45,7 +45,18 @@
 	__u64 steal;
 	__u32 version;
 	__u32 flags;
-	__u32 pad[12];
+	__u8  preempted;
+	__u8  u8_pad[3];
+	__u32 pad[11];
+};
+
+#define KVM_CLOCK_PAIRING_WALLCLOCK 0
+struct kvm_clock_pairing {
+	__s64 sec;
+	__s64 nsec;
+	__u64 tsc;
+	__u32 flags;
+	__u32 pad[9];
 };
 
 #define KVM_STEAL_ALIGNMENT_BITS 5
Index: qemu/linux-headers/linux/kvm.h
===================================================================
--- qemu.orig/linux-headers/linux/kvm.h	2016-12-29 15:45:49.572379128 -0200
+++ qemu/linux-headers/linux/kvm.h	2017-01-31 09:47:45.740645314 -0200
@@ -651,6 +651,9 @@
 };
 
 /* for KVM_PPC_GET_PVINFO */
+
+#define KVM_PPC_PVINFO_FLAGS_EV_IDLE   (1<<0)
+
 struct kvm_ppc_pvinfo {
 	/* out */
 	__u32 flags;
@@ -682,8 +685,6 @@
 	struct kvm_ppc_one_seg_page_size sps[KVM_PPC_PAGE_SIZES_MAX_SZ];
 };
 
-#define KVM_PPC_PVINFO_FLAGS_EV_IDLE   (1<<0)
-
 #define KVMIO 0xAE
 
 /* machine type bits, to be used as argument to KVM_CREATE_VM */
@@ -870,6 +871,7 @@
 #define KVM_CAP_S390_USER_INSTR0 130
 #define KVM_CAP_MSI_DEVID 131
 #define KVM_CAP_PPC_HTM 132
+#define KVM_CAP_ALLOW_FREQ_HC 133
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -1280,6 +1282,8 @@
 #define KVM_S390_GET_IRQ_STATE	  _IOW(KVMIO, 0xb6, struct kvm_s390_irq_state)
 /* Available with KVM_CAP_X86_SMM */
 #define KVM_SMI                   _IO(KVMIO,   0xb7)
+#define KVM_SET_VCPU_ALLOW_FREQ_HC   _IO(KVMIO,   0xb8)
+#define KVM_GET_VCPU_ALLOW_FREQ_HC   _IO(KVMIO,   0xb9)
 
 #define KVM_DEV_ASSIGN_ENABLE_IOMMU	(1 << 0)
 #define KVM_DEV_ASSIGN_PCI_2_3		(1 << 1)
Index: qemu/linux-headers/linux/kvm_para.h
===================================================================
--- qemu.orig/linux-headers/linux/kvm_para.h	2016-12-29 15:45:22.416325243 -0200
+++ qemu/linux-headers/linux/kvm_para.h	2017-01-31 09:47:45.741645316 -0200
@@ -14,6 +14,7 @@
 #define KVM_EFAULT		EFAULT
 #define KVM_E2BIG		E2BIG
 #define KVM_EPERM		EPERM
+#define KVM_EOPNOTSUPP		95
 
 #define KVM_HC_VAPIC_POLL_IRQ		1
 #define KVM_HC_MMU_OP			2
@@ -23,6 +24,12 @@
 #define KVM_HC_MIPS_GET_CLOCK_FREQ	6
 #define KVM_HC_MIPS_EXIT_VM		7
 #define KVM_HC_MIPS_CONSOLE_OUTPUT	8
+#define KVM_HC_CLOCK_PAIRING		9
+#define KVM_HC_FREQ_UP			10
+#define KVM_HC_FREQ_DOWN		11
+#define KVM_HC_FREQ_MAX			12
+#define KVM_HC_FREQ_MIN			13
+
 
 /*
  * hypercalls use architecture specific

[patch 2/2] kvm: introduce cpu flag to enable cpu frequency changes via hypercall

[Marcelo Tosatti]

[-- Attachment #1: qemu-support-allow-freq-hc --]
[-- Type: text/plain, Size: 3370 bytes --]

Guests with DPDK, whose vcpus run isolated on physical CPUs, want
to control the frequency of such physical CPUs.

Introduce a allow-freq-hc CPU flag to enable such hypercalls.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

---
 target/i386/cpu.c      |    1 +
 target/i386/cpu.h      |    6 ++++++
 target/i386/kvm.c      |   29 +++++++++++++++++++++++++++++
 target/i386/kvm_i386.h |    1 +
 4 files changed, 37 insertions(+)

Index: qemu/target/i386/cpu.c
===================================================================
--- qemu.orig/target/i386/cpu.c	2017-01-31 09:18:52.944948296 -0200
+++ qemu/target/i386/cpu.c	2017-01-31 09:47:58.050671578 -0200
@@ -3659,6 +3659,7 @@
     DEFINE_PROP_BOOL("lmce", X86CPU, enable_lmce, false),
     DEFINE_PROP_BOOL("l3-cache", X86CPU, enable_l3_cache, true),
     DEFINE_PROP_BOOL("vmware-cpuid-freq", X86CPU, vmware_cpuid_freq, true),
+    DEFINE_PROP_BOOL("allow-freq-hc", X86CPU, allow_freq_hc, false),
     DEFINE_PROP_END_OF_LIST()
 };
 
Index: qemu/target/i386/cpu.h
===================================================================
--- qemu.orig/target/i386/cpu.h	2017-01-31 09:18:52.944948296 -0200
+++ qemu/target/i386/cpu.h	2017-01-31 09:47:58.051671580 -0200
@@ -1243,6 +1243,12 @@
      */
     bool enable_l3_cache;
 
+    /* Direct frequency hypercalls from guest userspace can be
+     * enabled/disabled via cpu option 'allow_freq_hc=on/off'.
+     * It is disabled by default.
+     */
+    bool allow_freq_hc;
+
     /* Compatibility bits for old machine types: */
     bool enable_cpuid_0xb;
 
Index: qemu/target/i386/kvm.c
===================================================================
--- qemu.orig/target/i386/kvm.c	2017-01-31 09:18:52.944948296 -0200
+++ qemu/target/i386/kvm.c	2017-01-31 10:05:01.546855265 -0200
@@ -163,6 +163,11 @@
              has_x2apic_api);
 }
 
+bool kvm_has_allow_freq_hc(void)
+{
+    return kvm_check_extension(kvm_state, KVM_CAP_ALLOW_FREQ_HC);
+}
+
 static int kvm_get_tsc(CPUState *cs)
 {
     X86CPU *cpu = X86_CPU(cs);
@@ -692,6 +697,15 @@
     return 0;
 }
 
+static int kvm_set_vcpu_allow_freq(X86CPU *cpu)
+{
+    struct kvm_vcpu_allow_freq fr;
+
+    fr.enable = 1;
+
+    return kvm_vcpu_ioctl(CPU(cpu), KVM_SET_VCPU_ALLOW_FREQ_HC, &fr);
+}
+
 static Error *invtsc_mig_blocker;
 
 #define KVM_MAX_CPUID_ENTRIES  100
@@ -1040,6 +1054,21 @@
         has_msr_tsc_aux = false;
     }
 
+    if (cpu->allow_freq_hc) {
+        int ret;
+
+        if (!kvm_has_allow_freq_hc()) {
+            error_report("kvm: allow freq hypercall not supported");
+            return -ENOTSUP;
+        }
+
+        ret = kvm_set_vcpu_allow_freq(cpu);
+        if (ret) {
+            error_report("kvm: kvm_set_allow_freq failure, ret=%d", ret);
+            return ret;
+        }
+    }
+
     return 0;
 
  fail:
Index: qemu/target/i386/kvm_i386.h
===================================================================
--- qemu.orig/target/i386/kvm_i386.h	2017-01-31 09:18:52.944948296 -0200
+++ qemu/target/i386/kvm_i386.h	2017-01-31 09:47:58.052671582 -0200
@@ -21,6 +21,7 @@
 void kvm_synchronize_all_tsc(void);
 void kvm_arch_reset_vcpu(X86CPU *cs);
 void kvm_arch_do_init_vcpu(X86CPU *cs);
+bool kvm_has_allow_freq_hc(void);
 
 int kvm_device_pci_assign(KVMState *s, PCIHostDeviceAddress *dev_addr,
                           uint32_t flags, uint32_t *dev_id);