From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37734) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a14Mt-0001Ep-Ha for qemu-devel@nongnu.org; Mon, 23 Nov 2015 22:34:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a14Mq-0002t1-Bv for qemu-devel@nongnu.org; Mon, 23 Nov 2015 22:34:11 -0500 Received: from mga09.intel.com ([134.134.136.24]:40102) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a14Mq-0002st-6J for qemu-devel@nongnu.org; Mon, 23 Nov 2015 22:34:08 -0500 From: Haozhong Zhang Date: Tue, 24 Nov 2015 11:33:56 +0800 Message-Id: <1448336037-6035-3-git-send-email-haozhong.zhang@intel.com> In-Reply-To: <1448336037-6035-1-git-send-email-haozhong.zhang@intel.com> References: <1448336037-6035-1-git-send-email-haozhong.zhang@intel.com> Subject: [Qemu-devel] [PATCH v6 2/3] target-i386: reorganize TSC rate setting code List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, Eduardo Habkost , "Dr. David Alan Gilbert" Cc: Haozhong Zhang , kvm@vger.kernel.org, "Michael S. Tsirkin" , Marcelo Tosatti , Paolo Bonzini , afaerber@suse.de, Richard Henderson 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 --- 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 a0fe9d4..1e811ee 100644 --- a/target-i386/kvm.c +++ b/target-i386/kvm.c @@ -524,6 +524,36 @@ static bool hyperv_enabled(X86CPU *cpu) cpu->hyperv_runtime); } +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 @@ -823,13 +853,9 @@ 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 -- 2.4.8