From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: [patch 2/2] kvm: introduce cpu flag to enable cpu frequency changes via hypercall Date: Thu, 02 Feb 2017 15:53:34 -0200 Message-ID: <20170202180400.069973224@redhat.com> References: <20170202175332.346975248@redhat.com> Cc: Paolo Bonzini , Radim Krcmar , Marcelo Tosatti To: kvm@vger.kernel.org, qemu-devel@nongnu.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:53534 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752526AbdBBSE5 (ORCPT ); Thu, 2 Feb 2017 13:04:57 -0500 Content-Disposition: inline; filename=qemu-support-allow-freq-hc Sender: kvm-owner@vger.kernel.org List-ID: 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 --- 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);