From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50037) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aMGsX-0004Qq-Sy for qemu-devel@nongnu.org; Thu, 21 Jan 2016 10:10:35 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aMGsW-0006w5-O6 for qemu-devel@nongnu.org; Thu, 21 Jan 2016 10:10:29 -0500 Received: from mx1.redhat.com ([209.132.183.28]:34923) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aMGsW-0006vu-K3 for qemu-devel@nongnu.org; Thu, 21 Jan 2016 10:10:28 -0500 From: Eduardo Habkost Date: Thu, 21 Jan 2016 13:09:39 -0200 Message-Id: <1453388981-24807-11-git-send-email-ehabkost@redhat.com> In-Reply-To: <1453388981-24807-1-git-send-email-ehabkost@redhat.com> References: <1453388981-24807-1-git-send-email-ehabkost@redhat.com> Subject: [Qemu-devel] [PULL 10/12] target-i386: Reorganize TSC rate setting code List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell Cc: qemu-devel@nongnu.org, Paolo Bonzini , =?UTF-8?q?Andreas=20F=C3=A4rber?= , Haozhong Zhang , Richard Henderson From: Haozhong Zhang 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 1212b50..23d6b86 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 -- 2.1.0