linux-kernel - Re: [PATCH v8 03/14] KVM: X86: Don't track dirty for KVM_SET_[TSS_ADDR|IDENTITY_MAP

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20200428202228.GB4280@xz-x1>
Date:   Tue, 28 Apr 2020 16:22:28 -0400
From:   Peter Xu <peterx@...hat.com>
To:     Sean Christopherson <sean.j.christopherson@...el.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        Kevin Tian <kevin.tian@...el.com>,
        "Michael S . Tsirkin" <mst@...hat.com>,
        Jason Wang <jasowang@...hat.com>,
        Christophe de Dinechin <dinechin@...hat.com>,
        Yan Zhao <yan.y.zhao@...el.com>,
        Alex Williamson <alex.williamson@...hat.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        "Dr . David Alan Gilbert" <dgilbert@...hat.com>
Subject: Re: [PATCH v8 03/14] KVM: X86: Don't track dirty for
 KVM_SET_[TSS_ADDR|IDENTITY_MAP_ADDR]

On Mon, Apr 27, 2020 at 11:10:54AM -0700, Sean Christopherson wrote:

[...]

> > It will "return (0xdeadull << 48)" as you proposed in abbed4fa94f6? :-)
> > 
> > Frankly speaking I always preferred zero but that's just not true any more
> > after above change.  This also reminded me that maybe we should also return the
> > same thing at [1] below.
> 
> Ah, I was looking at this code:
> 
> 	if (!slot || !slot->npages)
> 		return 0;
> 
> That means deletion returns different success values for "deletion was a
> nop" and "deletion was successful".  The nop path should probably return
> (or fill in) "(unsigned long)(0xdeadull << 48)" as well.

Yep.  Since I touched the line here after all, I'll directly squash this small
fix into this patch too when I repost.  Thanks,

[...]

> > > 
> > > >  	} else {
> > > >  		if (!slot || !slot->npages)
> > > > -			return 0;
> > > > +			return ERR_PTR_USR(0);
> > 
> > [1]

-- 
Peter Xu