linux-kernel - Re: [PATCH RESEND v4 8/9] KVM: MMU: Enable Lazy mode SPPT setup

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Message-ID: <63f8952b-2497-16ec-ff55-1da017c50a8c@redhat.com>
Date:   Mon, 19 Aug 2019 16:46:54 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Yang Weijiang <weijiang.yang@...el.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, sean.j.christopherson@...el.com
Cc:     mst@...hat.com, rkrcmar@...hat.com, jmattson@...gle.com,
        yu.c.zhang@...el.com, alazar@...defender.com
Subject: Re: [PATCH RESEND v4 8/9] KVM: MMU: Enable Lazy mode SPPT setup

On 14/08/19 09:04, Yang Weijiang wrote:
> +
> +	if (vcpu->kvm->arch.spp_active && level == PT_PAGE_TABLE_LEVEL)
> +		kvm_enable_spp_protection(vcpu->kvm, gfn);
> +

This would not enable SPP if the guest is backed by huge pages.
Instead, either the PT_PAGE_TABLE_LEVEL level must be forced for all
pages covered by SPP ranges, or (better) kvm_enable_spp_protection must
be able to cover multiple pages at once.

Paolo