From 5031283d5296dac8d410fa7b01fb6799ccfc76e9 Mon Sep 17 00:00:00 2001 From: Haozhong Zhang Date: Tue, 24 Nov 2015 11:33:56 +0800 Subject: [PATCH] target-i386: Reorganize TSC rate setting code Following changes are made to the TSC rate setting code in kvm_arch_init_vcpu(): * The code is moved to a new function kvm_arch_set_tsc_khz(). * If kvm_arch_set_tsc_khz() fails, i.e. following two conditions are both satisfied: * KVM does not support the TSC scaling or it fails to set vcpu's TSC rate by KVM_SET_TSC_KHZ, * the TSC rate to be set is different than the value currently used by KVM, then kvm_arch_init_vcpu() will fail. Prevously, * the lack of TSC scaling never failed kvm_arch_init_vcpu(), * the failure of KVM_SET_TSC_KHZ failed kvm_arch_init_vcpu() unconditionally, even though the TSC rate to be set is identical to the value currently used by KVM. Signed-off-by: Haozhong Zhang Reviewed-by: Eduardo Habkost Signed-off-by: Eduardo Habkost --- target-i386/kvm.c | 40 +++++++++++++++++++++++++++++++++------- 1 file changed, 33 insertions(+), 7 deletions(-) diff --git a/target-i386/kvm.c b/target-i386/kvm.c index 1212b507e7..23d6b869a3 100644 --- a/target-i386/kvm.c +++ b/target-i386/kvm.c @@ -532,6 +532,36 @@ static bool hyperv_enabled(X86CPU *cpu) cpu->hyperv_stimer); } +static int kvm_arch_set_tsc_khz(CPUState *cs) +{ + X86CPU *cpu = X86_CPU(cs); + CPUX86State *env = &cpu->env; + int r; + + if (!env->tsc_khz) { + return 0; + } + + r = kvm_check_extension(cs->kvm_state, KVM_CAP_TSC_CONTROL) ? + kvm_vcpu_ioctl(cs, KVM_SET_TSC_KHZ, env->tsc_khz) : + -ENOTSUP; + if (r < 0) { + /* When KVM_SET_TSC_KHZ fails, it's an error only if the current + * TSC frequency doesn't match the one we want. + */ + int cur_freq = kvm_check_extension(cs->kvm_state, KVM_CAP_GET_TSC_KHZ) ? + kvm_vcpu_ioctl(cs, KVM_GET_TSC_KHZ) : + -ENOTSUP; + if (cur_freq <= 0 || cur_freq != env->tsc_khz) { + error_report("warning: TSC frequency mismatch between " + "VM and host, and TSC scaling unavailable"); + return r; + } + } + + return 0; +} + static Error *invtsc_mig_blocker; #define KVM_MAX_CPUID_ENTRIES 100 @@ -859,13 +889,9 @@ int kvm_arch_init_vcpu(CPUState *cs) return r; } - r = kvm_check_extension(cs->kvm_state, KVM_CAP_TSC_CONTROL); - if (r && env->tsc_khz) { - r = kvm_vcpu_ioctl(cs, KVM_SET_TSC_KHZ, env->tsc_khz); - if (r < 0) { - fprintf(stderr, "KVM_SET_TSC_KHZ failed\n"); - return r; - } + r = kvm_arch_set_tsc_khz(cs); + if (r < 0) { + return r; } /* vcpu's TSC frequency is either specified by user, or following -- 2.11.0