From f51c618ce3598d9a6a3256e4dd2b9dd3164fbc81 Mon Sep 17 00:00:00 2001 From: Eduardo Habkost Date: Thu, 23 Feb 2017 14:29:36 +0100 Subject: [PATCH 06/17] target-i386: kvm_cpu_fill_host(): No need to check xlevel2 RH-Author: Eduardo Habkost Message-id: <20170223142945.17790-6-ehabkost@redhat.com> Patchwork-id: 74036 O-Subject: [RHEL-7.4 qemu-kvm PATCH v2 05/14] target-i386: kvm_cpu_fill_host(): No need to check xlevel2 Bugzilla: 1382122 RH-Acked-by: Paolo Bonzini RH-Acked-by: Igor Mammedov RH-Acked-by: Miroslav Rezanina There's no need to check CPU xlevel2 before calling kvm_arch_get_supported_cpuid(s, 0xC0000001, 0, R_EDX), because: * The kernel won't return any entry for 0xC0000000 if host CPU vendor is not Centaur (See kvm_dev_ioctl_get_supported_cpuid() on the kernel code) * Similarly, the kernel won't return any entry for 0xC0000001 if CPUID[0xC0000000].EAX is < 0xC0000001 * kvm_arch_get_supported_cpuid() will return 0 if no entry is returned by the kernel for the requested leaf For similar reasons, we can simply set x86_cpu_def->xlevel2 directly instead of making it conditional, because it will be set to 0 CPU vendor is not Centaur. This will simplify the kvm_cpu_fill_host() code a little. Signed-off-by: Eduardo Habkost [Remove unparseable comment. - Paolo] Signed-off-by: Paolo Bonzini (cherry picked from commit 803a932706e3ba335d4c98f3577a05cb000f1699) Signed-off-by: Eduardo Habkost Signed-off-by: Miroslav Rezanina --- target-i386/cpu.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/target-i386/cpu.c b/target-i386/cpu.c index a10055b..02bd038 100644 --- a/target-i386/cpu.c +++ b/target-i386/cpu.c @@ -1285,13 +1285,10 @@ static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def) cpu_x86_fill_model_id(x86_cpu_def->model_id); /* Call Centaur's CPUID instruction. */ - eax = kvm_arch_get_supported_cpuid(s, 0xC0000000, 0, R_EAX); - if (eax >= 0xC0000001) { - /* Support VIA max extended level */ - x86_cpu_def->xlevel2 = eax; - x86_cpu_def->features[FEAT_C000_0001_EDX] = - kvm_arch_get_supported_cpuid(s, 0xC0000001, 0, R_EDX); - } + x86_cpu_def->xlevel2 = + kvm_arch_get_supported_cpuid(s, 0xC0000000, 0, R_EAX); + x86_cpu_def->features[FEAT_C000_0001_EDX] = + kvm_arch_get_supported_cpuid(s, 0xC0000001, 0, R_EDX); /* Other KVM-specific feature fields: */ x86_cpu_def->features[FEAT_SVM] = -- 1.8.3.1