From: Sean Christopherson <seanjc@google.com>
To: paul@xen.org
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Paul Durrant <pdurrant@amazon.com>,
David Woodhouse <dwmw@amazon.co.uk>,
David Woodhouse <dwmw2@infradead.org>,
Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH v7 04/11] KVM: pfncache: base offset check on khva rather than gpa
Date: Fri, 3 Nov 2023 16:10:14 -0700 [thread overview]
Message-ID: <ZUV91k9cUZt9jTbm@google.com> (raw)
In-Reply-To: <b47e82a4-2c01-4207-b4f8-296243061202@xen.org>
On Thu, Nov 02, 2023, Paul Durrant wrote:
> On 31/10/2023 23:40, Sean Christopherson wrote:
> > On Mon, Oct 02, 2023, Paul Durrant wrote:
> > > From: Paul Durrant <pdurrant@amazon.com>
> > >
> > > After a subsequent patch, the gpa may not always be set whereas khva will
> > > (as long as the cache valid flag is also set).
> >
> > This holds true only because there are no users of KVM_GUEST_USES_PFN, and
> > because hva_to_pfn_retry() rather oddly adds the offset to a NULL khva.
> >
> > I think it's time to admit using this to map PFNs into the guest is a bad idea
> > and rip out KVM_GUEST_USES_PFN before fully relying on khva.
> >
> > https://lore.kernel.org/all/ZQiR8IpqOZrOpzHC@google.com
>
> Is this something you want me to fix?
Yes? I don't want to snowball your series, but I also really don't like the
confusion that is introduced by relying on khva while KVM_GUEST_USES_PFN is still
a thing.
Can you give it a shot, and then holler if it's a bigger mess than I'm anticipating?
I'm assuming/hoping it's a relatively small, one-off patch, but I haven't actually
dug through in-depth to figure out what all needs to change.
next prev parent reply other threads:[~2023-11-03 23:10 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-02 9:57 [PATCH v7 00/11] KVM: xen: update shared_info and vcpu_info handling Paul Durrant
2023-10-02 9:57 ` [PATCH v7 01/11] KVM: pfncache: add a map helper function Paul Durrant
2023-10-31 23:20 ` Sean Christopherson
2023-11-02 17:09 ` Paul Durrant
2023-10-02 9:57 ` [PATCH v7 02/11] KVM: pfncache: add a mark-dirty helper Paul Durrant
2023-10-31 23:28 ` Sean Christopherson
2023-11-02 17:52 ` Paul Durrant
2023-11-03 23:07 ` Sean Christopherson
2023-10-02 9:57 ` [PATCH v7 03/11] KVM: pfncache: add a helper to get the gpa Paul Durrant
2023-10-31 23:37 ` Sean Christopherson
2023-10-02 9:57 ` [PATCH v7 04/11] KVM: pfncache: base offset check on khva rather than gpa Paul Durrant
2023-10-31 23:40 ` Sean Christopherson
2023-11-02 18:11 ` Paul Durrant
2023-11-03 23:10 ` Sean Christopherson [this message]
2023-10-02 9:57 ` [PATCH v7 05/11] KVM: pfncache: allow a cache to be activated with a fixed (userspace) HVA Paul Durrant
2023-10-31 23:49 ` Sean Christopherson
2023-11-02 18:01 ` Paul Durrant
2023-11-03 23:12 ` Sean Christopherson
2023-10-02 9:57 ` [PATCH v7 06/11] KVM: xen: allow shared_info to be mapped by fixed HVA Paul Durrant
2023-10-31 23:52 ` Sean Christopherson
2023-10-02 9:57 ` [PATCH v7 07/11] KVM: xen: allow vcpu_info " Paul Durrant
2023-10-02 9:57 ` [PATCH v7 08/11] KVM: selftests / xen: map shared_info using HVA rather than GFN Paul Durrant
2023-10-02 9:57 ` [PATCH v7 09/11] KVM: selftests / xen: re-map vcpu_info using HVA rather than GPA Paul Durrant
2023-10-02 9:57 ` [PATCH v7 10/11] KVM: xen: advertize the KVM_XEN_HVM_CONFIG_SHARED_INFO_HVA capability Paul Durrant
2023-10-02 9:57 ` [PATCH v7 11/11] KVM: xen: allow vcpu_info content to be 'safely' copied Paul Durrant
2023-10-31 23:58 ` Sean Christopherson
2023-11-08 15:15 ` David Woodhouse
2023-11-08 20:55 ` Sean Christopherson
2023-11-08 21:56 ` David Woodhouse
2023-10-05 6:41 ` [PATCH v7 00/11] KVM: xen: update shared_info and vcpu_info handling David Woodhouse
2023-10-05 8:36 ` Paul Durrant
2023-11-09 10:02 ` David Woodhouse
2023-11-09 10:06 ` Paul Durrant
2023-10-30 12:00 ` Paul Durrant
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