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Date:   Tue, 12 Apr 2022 19:30:17 +0000
From:   Sean Christopherson <seanjc@google.com>
To:     Ben Gardon <bgardon@google.com>
Cc:     linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        Paolo Bonzini <pbonzini@redhat.com>,
        Peter Xu <peterx@redhat.com>,
        David Matlack <dmatlack@google.com>,
        Jim Mattson <jmattson@google.com>,
        David Dunn <daviddunn@google.com>,
        Jing Zhang <jingzhangos@google.com>,
        Junaid Shahid <junaids@google.com>
Subject: Re: [PATCH v2 7/9] KVM: x86/mmu: Add try_get_mt_mask to x86_ops
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On Mon, Apr 11, 2022, Sean Christopherson wrote:
> It's obviously not a hard dependency, but using a u64 for the mask here and then
> undoing the whole thing is rather silly.  Compile tested only at this point, I'll
> test on an actual system ASAP and let you know if I did something stupid.
> 
> From: Sean Christopherson <seanjc@google.com>
> Date: Mon, 11 Apr 2022 15:12:16 -0700
> Subject: [PATCH] KVM: x86: Restrict get_mt_mask() to a u8, use
>  KVM_X86_OP_OPTIONAL_RET0

Verified this works as expected when patching in RET0 on a 32-bit kernel (returning
a u64 results in reserved bits in the upper half being set due to EDX not being cleared).