linux-kernel - Re: [PATCH v6 4/5] KVM: VMX: Allow direct access to MSR_IA32_SPEC

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Date:   Fri, 2 Feb 2018 12:53:52 -0500
From:   Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:     KarimAllah Ahmed <karahmed@...zon.de>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org, x86@...nel.org,
        Asit Mallick <asit.k.mallick@...el.com>,
        Arjan Van De Ven <arjan.van.de.ven@...el.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Dan Williams <dan.j.williams@...el.com>,
        Jun Nakajima <jun.nakajima@...el.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        David Woodhouse <dwmw@...zon.co.uk>,
        Greg KH <gregkh@...uxfoundation.org>,
        Andy Lutomirski <luto@...nel.org>,
        Ashok Raj <ashok.raj@...el.com>
Subject: Re: [PATCH v6 4/5] KVM: VMX: Allow direct access to
 MSR_IA32_SPEC_CTRL

.snip..
> @@ -1913,6 +1914,29 @@ static void update_exception_bitmap(struct kvm_vcpu *vcpu)
>  }
>  
>  /*
> + * Check if MSR is intercepted for currently loaded MSR bitmap.
> + */
> +static bool msr_write_intercepted(struct kvm_vcpu *vcpu, u32 msr)
> +{
> +	unsigned long *msr_bitmap;
> +	int f = sizeof(unsigned long);

unsigned int
> +
> +	if (!cpu_has_vmx_msr_bitmap())
> +		return true;
> +
> +	msr_bitmap = to_vmx(vcpu)->loaded_vmcs->msr_bitmap;
> +
> +	if (msr <= 0x1fff) {
> +		return !!test_bit(msr, msr_bitmap + 0x800 / f);
> +	} else if ((msr >= 0xc0000000) && (msr <= 0xc0001fff)) {
> +		msr &= 0x1fff;
> +		return !!test_bit(msr, msr_bitmap + 0xc00 / f);
> +	}
> +
> +	return true;
> +}

with that:

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>