linux-kernel - Re: [PATCH v3 2/6] KVM: nVMX: Enable nested virtualize x2apic mode.

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Message-ID: <54C804FD.6060108@redhat.com>
Date:	Tue, 27 Jan 2015 22:37:01 +0100
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	Wincy Van <fanwenyi0529@...il.com>,
	"gleb@...nel.org" <gleb@...nel.org>,
	"Zhang, Yang Z" <yang.z.zhang@...el.com>
CC:	"kvm@...r.kernel.org" <kvm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Wanpeng Li <wanpeng.li@...ux.intel.com>,
	Jan Kiszka <jan.kiszka@....de>
Subject: Re: [PATCH v3 2/6] KVM: nVMX: Enable nested virtualize x2apic mode.



On 24/01/2015 11:21, Wincy Van wrote:
> +       memset(vmx_msr_bitmap_nested, 0xff, PAGE_SIZE);

Most bytes are always 0xff.  It's better to initialize it to 0xff once,
and set the bit here if !nested_cpu_has_virt_x2apic_mode(vmcs12).

> +       if (nested_cpu_has_virt_x2apic_mode(vmcs12))

Please add braces here, because of the /* */ command below.

> +               /* TPR is allowed */
> +               nested_vmx_disable_intercept_for_msr(msr_bitmap,
> +                               vmx_msr_bitmap_nested,
> +                               APIC_BASE_MSR + (APIC_TASKPRI >> 4),
> +                               MSR_TYPE_R | MSR_TYPE_W);
> 
> +static inline int nested_vmx_check_virt_x2apic(struct kvm_vcpu *vcpu,
> +                                              struct vmcs12 *vmcs12)
> +{
> +       if (nested_cpu_has2(vmcs12, SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES))
> +               return -EINVAL;

No need for this function and nested_cpu_has_virt_x2apic_mode.  Just
inline them in their caller(s).  Same for other cases throughout the series.

Paolo

> +       return 0;
> +}
> +
> +static int nested_vmx_check_apicv_controls(struct kvm_vcpu *vcpu,
> +                                          struct vmcs12 *vmcs12)
> +{
> +       int r;
> +
> +       if (!nested_cpu_has_virt_x2apic_mode(vmcs12))
> +               return 0;
> +
> +       r = nested_vmx_check_virt_x2apic(vcpu, vmcs12);
> +       if (r)
> +               goto fail;
> +
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