| Message ID | CADJev798OQb2CGNysQP=RQGdM7eEYoZX8pjLtx5Kur7r0p4BSA@mail.gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
2016-12-09 10:12-0500, Don Bowman: > OK, based on previous feedback, this patch version simply ignores any > inconsistency if a knowing and trusting user wishes. > > In my case, two identical processors in stepping and version and all > others have 1 flag missing (retail vs tray version of chip), but the > next person might have another flag. > > Comments? > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 5382b82..264870e 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -103,6 +103,9 @@ module_param_named(enable_shadow_vmcs, > enable_shadow_vmcs, bool, S_IRUGO); > static bool __read_mostly nested = 0; > module_param(nested, bool, S_IRUGO); > > +static bool __read_mostly ignore_inconsistency = false; > +module_param(ignore_inconsistency, bool, S_IRUGO); > + > static u64 __read_mostly host_xss; > > static bool __read_mostly enable_pml = 1; > @@ -3449,6 +3452,7 @@ static __init int setup_vmcs_config(struct > vmcs_config *vmcs_conf) > vmcs_conf->pin_based_exec_ctrl = _pin_based_exec_control; > vmcs_conf->cpu_based_exec_ctrl = _cpu_based_exec_control; > vmcs_conf->cpu_based_2nd_exec_ctrl = _cpu_based_2nd_exec_control; > + vmcs_conf->cpu_based_2nd_exec_ctrl &= ~SECONDARY_EXEC_TSC_SCALING; This would disable TSC_SCALING for everyone. You need a second patch that makes tsc_scaling optional. > vmcs_conf->vmexit_ctrl = _vmexit_control; > vmcs_conf->vmentry_ctrl = _vmentry_control; > > @@ -9202,9 +9206,11 @@ static void __init vmx_check_processor_compat(void *rtn) > if (setup_vmcs_config(&vmcs_conf) < 0) > *(int *)rtn = -EIO; > if (memcmp(&vmcs_config, &vmcs_conf, sizeof(struct vmcs_config)) != 0) { > - printk(KERN_ERR "kvm: CPU %d feature inconsistency!\n", > - smp_processor_id()); > - *(int *)rtn = -EIO; > + printk(KERN_ERR "kvm: CPU %d feature inconsistency%s!\n", > + smp_processor_id(), > + ignore_inconsistency ? " -- ignored" : ""); > + if (!ignore_inconsistency) > + *(int *)rtn = -EIO; Please add a note in the spirit of: "KVM is going to fail unless you explicitly disable features that are not present on all CPUs." If this becomes a normal feature, we'd remove the toggle, check that all enabled features are supported, and pass if KVM will work with selected features ... the check seems like a waste of code for this rarity of machines. Paolo, are you ok with the toggle? (We can just make it the default without any significant issues.) Thanks. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 13/12/2016 16:43, Radim Krčmář wrote: > Paolo, are you ok with the toggle? > (We can just make it the default without any significant issues.) I don't know... It's ugly and it seems like nothing but an Intel mess-up. On ark.intel.com 2696v3 doesn't exist and 2699v3 is listed as Announced rather than Launched. I'm okay with a simple patch to disable TSC scaling, but I'm not sure it's worth doing anything more than that. Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 5382b82..264870e 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -103,6 +103,9 @@ module_param_named(enable_shadow_vmcs, enable_shadow_vmcs, bool, S_IRUGO); static bool __read_mostly nested = 0; module_param(nested, bool, S_IRUGO); +static bool __read_mostly ignore_inconsistency = false; +module_param(ignore_inconsistency, bool, S_IRUGO); + static u64 __read_mostly host_xss;
OK, based on previous feedback, this patch version simply ignores any inconsistency if a knowing and trusting user wishes. In my case, two identical processors in stepping and version and all others have 1 flag missing (retail vs tray version of chip), but the next person might have another flag. Comments? static bool __read_mostly enable_pml = 1; @@ -3449,6 +3452,7 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf) vmcs_conf->pin_based_exec_ctrl = _pin_based_exec_control; vmcs_conf->cpu_based_exec_ctrl = _cpu_based_exec_control; vmcs_conf->cpu_based_2nd_exec_ctrl = _cpu_based_2nd_exec_control; + vmcs_conf->cpu_based_2nd_exec_ctrl &= ~SECONDARY_EXEC_TSC_SCALING; vmcs_conf->vmexit_ctrl = _vmexit_control; vmcs_conf->vmentry_ctrl = _vmentry_control; @@ -9202,9 +9206,11 @@ static void __init vmx_check_processor_compat(void *rtn) if (setup_vmcs_config(&vmcs_conf) < 0) *(int *)rtn = -EIO; if (memcmp(&vmcs_config, &vmcs_conf, sizeof(struct vmcs_config)) != 0) { - printk(KERN_ERR "kvm: CPU %d feature inconsistency!\n", - smp_processor_id()); - *(int *)rtn = -EIO; + printk(KERN_ERR "kvm: CPU %d feature inconsistency%s!\n", + smp_processor_id(), + ignore_inconsistency ? " -- ignored" : ""); + if (!ignore_inconsistency) + *(int *)rtn = -EIO; } } -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html