linux-kernel - Re: [PATCH RESEND v2 03/17] KVM: X86: Don't track dirty for KVM_SET_[TSS_ADDR|IDENTITY_MAP

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Message-ID: <20191223201024.GB90172@xz-x1>
Date:   Mon, 23 Dec 2019 15:10:24 -0500
From:   Peter Xu <peterx@...hat.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        "Dr . David Alan Gilbert" <dgilbert@...hat.com>,
        Christophe de Dinechin <dinechin@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        "Michael S . Tsirkin" <mst@...hat.com>,
        Jason Wang <jasowang@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>
Subject: Re: [PATCH RESEND v2 03/17] KVM: X86: Don't track dirty for
 KVM_SET_[TSS_ADDR|IDENTITY_MAP_ADDR]

On Mon, Dec 23, 2019 at 06:59:01PM +0100, Paolo Bonzini wrote:
> On 23/12/19 18:27, Peter Xu wrote:
> > Yes.  Though it is a bit tricky in that then we'll also need to make
> > sure to take slots_lock or srcu to protect that hva (say, we must drop
> > that hva reference before we release the locks, otherwise the hva
> > could gone under us, iiuc).
> 
> Yes, kvm->slots_lock is taken by x86_set_memory_region.  We need to move
> that to the callers, of which several are already taking the lock (all
> except vmx_set_tss_addr and kvm_arch_destroy_vm).

OK, will do.  I'll directly replace the x86_set_memory_region() calls
in kvm_arch_destroy_vm() to be __x86_set_memory_region() since IIUC
the slots_lock is helpless when destroying the vm... then drop the
x86_set_memory_region() helper in the next version.  Thanks,

-- 
Peter Xu