From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: virtio-fs-list <virtio-fs@redhat.com>,
pbonzini@redhat.com, kvm@vger.kernel.org,
Vivek Goyal <vgoyal@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [Virtio-fs] [PATCH v4] kvm, x86: Exit to user space in case page fault error
Date: Tue, 6 Oct 2020 09:12:00 -0700 [thread overview]
Message-ID: <20201006161200.GB17610@linux.intel.com> (raw)
In-Reply-To: <871rib8ji1.fsf@vitty.brq.redhat.com>
On Tue, Oct 06, 2020 at 05:24:54PM +0200, Vitaly Kuznetsov wrote:
> Vivek Goyal <vgoyal@redhat.com> writes:
> > So you will have to report token (along with -EFAULT) to user space. So this
> > is basically the 3rd proposal which is extension of kvm API and will
> > report say HVA/GFN also to user space along with -EFAULT.
>
> Right, I meant to say that guest kernel has full register state of the
> userspace process which caused APF to get queued and instead of trying
> to extract it in KVM and pass to userspace in case of a (later) failure
> we limit KVM api change to contain token or GFN only and somehow keep
> the rest in the guest. This should help with TDX/SEV-ES.
Whatever gets reported to userspace should be identical with and without
async page faults, i.e. it definitely shouldn't have token information.
Note, TDX doesn't allow injection exceptions, so reflecting a #PF back
into the guest is not an option. Nor do I think that's "correct"
behavior (see everyone's objections to using #PF for APF fixed). I.e. the
event should probably be an IRQ.
WARNING: multiple messages have this Message-ID (diff)
From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
virtio-fs-list <virtio-fs@redhat.com>,
pbonzini@redhat.com
Subject: Re: [PATCH v4] kvm,x86: Exit to user space in case page fault error
Date: Tue, 6 Oct 2020 09:12:00 -0700 [thread overview]
Message-ID: <20201006161200.GB17610@linux.intel.com> (raw)
In-Reply-To: <871rib8ji1.fsf@vitty.brq.redhat.com>
On Tue, Oct 06, 2020 at 05:24:54PM +0200, Vitaly Kuznetsov wrote:
> Vivek Goyal <vgoyal@redhat.com> writes:
> > So you will have to report token (along with -EFAULT) to user space. So this
> > is basically the 3rd proposal which is extension of kvm API and will
> > report say HVA/GFN also to user space along with -EFAULT.
>
> Right, I meant to say that guest kernel has full register state of the
> userspace process which caused APF to get queued and instead of trying
> to extract it in KVM and pass to userspace in case of a (later) failure
> we limit KVM api change to contain token or GFN only and somehow keep
> the rest in the guest. This should help with TDX/SEV-ES.
Whatever gets reported to userspace should be identical with and without
async page faults, i.e. it definitely shouldn't have token information.
Note, TDX doesn't allow injection exceptions, so reflecting a #PF back
into the guest is not an option. Nor do I think that's "correct"
behavior (see everyone's objections to using #PF for APF fixed). I.e. the
event should probably be an IRQ.
next prev parent reply other threads:[~2020-10-06 16:12 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-20 21:13 [Virtio-fs] [PATCH v4] kvm, x86: Exit to user space in case page fault error Vivek Goyal
2020-07-20 21:13 ` [PATCH v4] kvm,x86: " Vivek Goyal
2020-07-27 13:56 ` [Virtio-fs] [PATCH v4] kvm, x86: " Vivek Goyal
2020-07-27 13:56 ` [PATCH v4] kvm,x86: " Vivek Goyal
2020-07-27 16:09 ` [Virtio-fs] [PATCH v4] kvm, x86: " Vitaly Kuznetsov
2020-07-27 16:09 ` [PATCH v4] kvm,x86: " Vitaly Kuznetsov
2020-07-27 18:40 ` [Virtio-fs] [PATCH v4] kvm, x86: " Vivek Goyal
2020-07-27 18:40 ` [PATCH v4] kvm,x86: " Vivek Goyal
2020-07-30 5:01 ` [Virtio-fs] [PATCH v4] kvm, x86: " Pankaj Gupta
2020-07-30 5:01 ` [PATCH v4] kvm,x86: " Pankaj Gupta
2020-08-07 17:51 ` [Virtio-fs] [PATCH v4] kvm, x86: " Vivek Goyal
2020-08-07 17:51 ` [PATCH v4] kvm,x86: " Vivek Goyal
2020-09-29 4:37 ` [Virtio-fs] [PATCH v4] kvm, x86: " Sean Christopherson
2020-09-29 4:37 ` [PATCH v4] kvm,x86: " Sean Christopherson
2020-10-01 21:55 ` [Virtio-fs] [PATCH v4] kvm, x86: " Vivek Goyal
2020-10-01 21:55 ` [PATCH v4] kvm,x86: " Vivek Goyal
2020-10-01 22:33 ` [Virtio-fs] [PATCH v4] kvm, x86: " Sean Christopherson
2020-10-01 22:33 ` [PATCH v4] kvm,x86: " Sean Christopherson
2020-10-02 15:38 ` [Virtio-fs] [PATCH v4] kvm, x86: " Vivek Goyal
2020-10-02 15:38 ` [PATCH v4] kvm,x86: " Vivek Goyal
2020-10-02 18:30 ` [Virtio-fs] [PATCH v4] kvm, x86: " Sean Christopherson
2020-10-02 18:30 ` [PATCH v4] kvm,x86: " Sean Christopherson
2020-10-02 19:27 ` [Virtio-fs] [PATCH v4] kvm, x86: " Vivek Goyal
2020-10-02 19:27 ` [PATCH v4] kvm,x86: " Vivek Goyal
2020-10-02 19:45 ` [Virtio-fs] [PATCH v4] kvm, x86: " Sean Christopherson
2020-10-02 19:45 ` [PATCH v4] kvm,x86: " Sean Christopherson
2020-10-02 20:02 ` [Virtio-fs] [PATCH v4] kvm, x86: " Vivek Goyal
2020-10-02 20:02 ` [PATCH v4] kvm,x86: " Vivek Goyal
2020-10-02 21:13 ` [Virtio-fs] [PATCH v4] kvm, x86: " Sean Christopherson
2020-10-02 21:13 ` [PATCH v4] kvm,x86: " Sean Christopherson
2020-10-05 15:33 ` [Virtio-fs] [PATCH v4] kvm, x86: " Vivek Goyal
2020-10-05 15:33 ` [PATCH v4] kvm,x86: " Vivek Goyal
2020-10-05 16:16 ` [Virtio-fs] [PATCH v4] kvm, x86: " Sean Christopherson
2020-10-05 16:16 ` [PATCH v4] kvm,x86: " Sean Christopherson
2020-10-06 13:46 ` [Virtio-fs] [PATCH v4] kvm, x86: " Vivek Goyal
2020-10-06 13:46 ` [PATCH v4] kvm,x86: " Vivek Goyal
2020-10-06 14:05 ` [Virtio-fs] [PATCH v4] kvm, x86: " Vitaly Kuznetsov
2020-10-06 14:05 ` [PATCH v4] kvm,x86: " Vitaly Kuznetsov
2020-10-06 14:15 ` [Virtio-fs] [PATCH v4] kvm, x86: " Vivek Goyal
2020-10-06 14:15 ` [PATCH v4] kvm,x86: " Vivek Goyal
2020-10-06 14:50 ` [Virtio-fs] [PATCH v4] kvm, x86: " Vitaly Kuznetsov
2020-10-06 14:50 ` [PATCH v4] kvm,x86: " Vitaly Kuznetsov
2020-10-06 15:08 ` [Virtio-fs] [PATCH v4] kvm, x86: " Vivek Goyal
2020-10-06 15:08 ` [PATCH v4] kvm,x86: " Vivek Goyal
2020-10-06 15:24 ` [Virtio-fs] [PATCH v4] kvm, x86: " Vitaly Kuznetsov
2020-10-06 15:24 ` [PATCH v4] kvm,x86: " Vitaly Kuznetsov
2020-10-06 16:12 ` Sean Christopherson [this message]
2020-10-06 16:12 ` Sean Christopherson
2020-10-06 16:24 ` [Virtio-fs] [PATCH v4] kvm, x86: " Vivek Goyal
2020-10-06 16:24 ` [PATCH v4] kvm,x86: " Vivek Goyal
2020-10-06 16:39 ` [Virtio-fs] [PATCH v4] kvm, x86: " Vitaly Kuznetsov
2020-10-06 16:39 ` [PATCH v4] kvm,x86: " Vitaly Kuznetsov
2020-10-06 17:17 ` [Virtio-fs] [PATCH v4] kvm, x86: " Sean Christopherson
2020-10-06 17:17 ` [PATCH v4] kvm,x86: " Sean Christopherson
2020-10-06 17:21 ` [Virtio-fs] [PATCH v4] kvm, x86: " Dr. David Alan Gilbert
2020-10-06 17:21 ` Dr. David Alan Gilbert
2020-10-06 17:28 ` Vivek Goyal
2020-10-06 17:28 ` Vivek Goyal
2020-10-06 17:35 ` Vivek Goyal
2020-10-06 17:35 ` [PATCH v4] kvm,x86: " Vivek Goyal
2020-10-07 0:04 ` [Virtio-fs] [PATCH v4] kvm, x86: " Sean Christopherson
2020-10-07 0:04 ` [PATCH v4] kvm,x86: " Sean Christopherson
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