linux-kernel - Re: [PATCH] KVM: nVMX: Store vmcs.EXIT_QUALIFICATION as an unsigned long, not u32

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Date:   Fri, 24 Apr 2020 07:16:49 -0700
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Vitaly Kuznetsov <vkuznets@...hat.com>
Cc:     Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>
Subject: Re: [PATCH] KVM: nVMX: Store vmcs.EXIT_QUALIFICATION as an unsigned
 long, not u32

On Fri, Apr 24, 2020 at 01:44:00PM +0200, Vitaly Kuznetsov wrote:
> I also did 'git grep -W 'u32.*exit_qual' kvm/queue' and I can see a few
> more places where 'exit_qual' is u32:
> nested_vmx_check_guest_state()
> nested_vmx_enter_non_root_mode()
> vmx_set_nested_state()
> 
> Being too lazy to check an even if there are no immediate issues with
> that, should we just use 'unsigned long' everywhere?

Yes, absolutely, I'll send a patch.

The existing cases are benign, they're all related to setting the exit_qual
for a nested VM-Enter failure, which could fit in a u8.  But still worth
fixing.