From: Joao Martins <joao.m.martins@oracle.com>
To: Ankur Arora <ankur.a.arora@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH RFC 03/39] KVM: x86/xen: register shared_info page
Date: Wed, 2 Dec 2020 10:50:31 +0000 [thread overview]
Message-ID: <474f59b0-184d-12a1-4172-c65d8970810e@oracle.com> (raw)
In-Reply-To: <a6102420-cbda-700a-b049-31db96d357b1@oracle.com>
On 12/2/20 5:17 AM, Ankur Arora wrote:
> On 2020-12-01 5:26 p.m., David Woodhouse wrote
>> On Tue, 2020-12-01 at 16:40 -0800, Ankur Arora wrote:
>>> On 2020-12-01 5:07 a.m., David Woodhouse wrote:
[...]
>>>> If that was allowed, wouldn't it have been a much simpler fix for
>>>> CVE-2019-3016? What am I missing?
>>>
>>> Agreed.
>>>
>>> Perhaps, Paolo can chime in with why KVM never uses pinned page
>>> and always prefers to do cached mappings instead?
>>>
>>>>
>>>> Should I rework these to use kvm_write_guest_cached()?
>>>
>>> kvm_vcpu_map() would be better. The event channel logic does RMW operations
>>> on shared_info->vcpu_info.
>>
>> I've ported the shared_info/vcpu_info parts and made a test case, and
>> was going back through to make it use kvm_write_guest_cached(). But I
>> should probably plug on through the evtchn bits before I do that.
>>
>> I also don't see much locking on the cache, and can't convince myself
>> that accessing the shared_info page from multiple CPUs with
>> kvm_write_guest_cached() or kvm_map_gfn() is sane unless they each have
>> their own cache.
>
> I think you could get a VCPU specific cache with kvm_vcpu_map().
>
steal clock handling creates such a mapping cache (struct gfn_to_pfn_cache).
Joao
next prev parent reply other threads:[~2020-12-02 10:51 UTC|newest]
Thread overview: 126+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-20 20:15 [PATCH RFC 00/39] x86/KVM: Xen HVM guest support Joao Martins
2019-02-20 20:15 ` [PATCH RFC 01/39] KVM: x86: fix Xen hypercall page msr handling Joao Martins
2019-02-22 1:30 ` Sean Christopherson
2019-02-22 11:47 ` Joao Martins
2019-02-22 12:51 ` Paolo Bonzini
2020-11-30 10:39 ` David Woodhouse
2020-11-30 11:03 ` Paolo Bonzini
2020-11-30 11:27 ` David Woodhouse
2019-02-20 20:15 ` [PATCH RFC 02/39] KVM: x86/xen: intercept xen hypercalls if enabled Joao Martins
2019-02-21 18:29 ` Sean Christopherson
2019-02-21 20:56 ` Joao Martins
2019-02-22 0:30 ` Sean Christopherson
2019-02-22 12:50 ` Paolo Bonzini
2020-12-01 9:48 ` David Woodhouse
2020-12-01 11:19 ` David Woodhouse
2020-12-02 11:17 ` Joao Martins
2020-12-02 12:12 ` David Woodhouse
2020-12-02 5:19 ` Ankur Arora
2020-12-02 8:03 ` David Woodhouse
2020-12-02 18:20 ` Ankur Arora
2019-02-20 20:15 ` [PATCH RFC 03/39] KVM: x86/xen: register shared_info page Joao Martins
2020-12-01 13:07 ` David Woodhouse
2020-12-02 0:40 ` Ankur Arora
2020-12-02 1:26 ` David Woodhouse
2020-12-02 5:17 ` Ankur Arora
2020-12-02 10:50 ` Joao Martins [this message]
2020-12-02 10:44 ` Joao Martins
2020-12-02 12:20 ` David Woodhouse
2020-12-02 20:32 ` Ankur Arora
2020-12-03 10:16 ` David Woodhouse
2020-12-04 17:30 ` Sean Christopherson
2020-12-02 20:33 ` Ankur Arora
2020-12-12 12:07 ` David Woodhouse
2019-02-20 20:15 ` [PATCH RFC 04/39] KVM: x86/xen: setup pvclock updates Joao Martins
2019-02-20 20:15 ` [PATCH RFC 05/39] KVM: x86/xen: update wallclock region Joao Martins
2019-02-20 20:15 ` [PATCH RFC 06/39] KVM: x86/xen: register vcpu info Joao Martins
2019-02-20 20:15 ` [PATCH RFC 07/39] KVM: x86/xen: register vcpu time info region Joao Martins
2019-02-20 20:15 ` [PATCH RFC 08/39] KVM: x86/xen: register steal clock Joao Martins
2019-02-20 20:15 ` [PATCH RFC 09/39] KVM: x86: declare Xen HVM guest capability Joao Martins
2019-02-20 20:15 ` [PATCH RFC 10/39] KVM: x86/xen: support upcall vector Joao Martins
2020-12-02 11:17 ` David Woodhouse
2020-12-02 13:12 ` Joao Martins
2020-12-02 16:47 ` David Woodhouse
2020-12-02 18:34 ` Joao Martins
2020-12-02 19:02 ` David Woodhouse
2020-12-02 20:12 ` Joao Martins
2020-12-02 20:37 ` David Woodhouse
2020-12-03 1:08 ` Ankur Arora
2020-12-08 16:08 ` David Woodhouse
2020-12-09 6:35 ` Ankur Arora
2020-12-09 10:27 ` David Woodhouse
2020-12-09 10:51 ` Joao Martins
2020-12-09 11:39 ` David Woodhouse
2020-12-09 13:26 ` Joao Martins
2020-12-09 15:41 ` David Woodhouse
2020-12-09 16:12 ` Joao Martins
2021-01-01 14:33 ` David Woodhouse
2021-01-05 12:11 ` Joao Martins
2021-01-05 13:23 ` David Woodhouse
2019-02-20 20:15 ` [PATCH RFC 11/39] KVM: x86/xen: evtchn signaling via eventfd Joao Martins
2020-11-30 9:41 ` David Woodhouse
2020-11-30 12:17 ` Joao Martins
2020-11-30 12:55 ` David Woodhouse
2020-11-30 15:08 ` Joao Martins
2020-11-30 16:48 ` David Woodhouse
2020-11-30 17:15 ` Joao Martins
2020-11-30 18:01 ` David Woodhouse
2020-11-30 18:41 ` Joao Martins
2020-11-30 19:04 ` David Woodhouse
2020-11-30 19:25 ` Joao Martins
2021-11-23 13:15 ` David Woodhouse
2019-02-20 20:15 ` [PATCH RFC 12/39] KVM: x86/xen: store virq when assigning evtchn Joao Martins
[not found] ` <b750291466f3c89e0a393e48079c087704b217a5.camel@amazon.co.uk>
2022-02-10 12:17 ` Joao Martins
2022-02-10 15:23 ` [EXTERNAL] " David Woodhouse
2019-02-20 20:15 ` [PATCH RFC 13/39] KVM: x86/xen: handle PV timers oneshot mode Joao Martins
2019-02-20 20:15 ` [PATCH RFC 14/39] KVM: x86/xen: handle PV IPI vcpu yield Joao Martins
2019-02-20 20:15 ` [PATCH RFC 15/39] KVM: x86/xen: handle PV spinlocks slowpath Joao Martins
2022-02-08 12:36 ` David Woodhouse
2022-02-10 12:17 ` Joao Martins
2022-02-10 14:11 ` David Woodhouse
2019-02-20 20:15 ` [PATCH RFC 16/39] KVM: x86: declare Xen HVM evtchn offload capability Joao Martins
2019-02-20 20:15 ` [PATCH RFC 17/39] x86/xen: export vcpu_info and shared_info Joao Martins
2019-02-20 20:15 ` [PATCH RFC 18/39] x86/xen: make hypercall_page generic Joao Martins
2019-02-20 20:15 ` [PATCH RFC 19/39] xen/xenbus: xenbus uninit support Joao Martins
2019-02-20 20:15 ` [PATCH RFC 20/39] xen-blkback: module_exit support Joao Martins
2019-02-25 18:57 ` Konrad Rzeszutek Wilk
2019-02-26 11:20 ` Joao Martins
2019-02-20 20:15 ` [PATCH RFC 21/39] KVM: x86/xen: domid allocation Joao Martins
2019-02-20 20:15 ` [PATCH RFC 22/39] KVM: x86/xen: grant table init Joao Martins
2019-02-20 20:15 ` [PATCH RFC 23/39] KVM: x86/xen: grant table grow support Joao Martins
2019-02-20 20:15 ` [PATCH RFC 24/39] KVM: x86/xen: backend hypercall support Joao Martins
2019-02-20 20:15 ` [PATCH RFC 25/39] KVM: x86/xen: grant map support Joao Martins
2019-02-20 20:15 ` [PATCH RFC 26/39] KVM: x86/xen: grant unmap support Joao Martins
2019-02-20 20:15 ` [PATCH RFC 27/39] KVM: x86/xen: grant copy support Joao Martins
2019-02-20 20:15 ` [PATCH RFC 28/39] KVM: x86/xen: interdomain evtchn support Joao Martins
2019-02-20 20:15 ` [PATCH RFC 29/39] KVM: x86/xen: evtchn unmask support Joao Martins
2019-02-20 20:16 ` [PATCH RFC 30/39] KVM: x86/xen: add additional evtchn ops Joao Martins
2019-02-20 20:16 ` [PATCH RFC 31/39] xen-shim: introduce shim domain driver Joao Martins
2019-02-20 20:16 ` [PATCH RFC 32/39] xen/balloon: xen_shim_domain() support Joao Martins
2019-02-20 20:16 ` [PATCH RFC 33/39] xen/grant-table: " Joao Martins
2019-02-20 20:16 ` [PATCH RFC 34/39] xen/gntdev: " Joao Martins
2019-02-20 20:16 ` [PATCH RFC 35/39] xen/xenbus: " Joao Martins
2019-02-20 20:16 ` [PATCH RFC 36/39] drivers/xen: " Joao Martins
2019-02-20 20:16 ` [PATCH RFC 37/39] xen-netback: " Joao Martins
2019-02-20 20:16 ` [PATCH RFC 38/39] xen-blkback: " Joao Martins
2019-02-20 20:16 ` [PATCH RFC 39/39] KVM: x86: declare Xen HVM Dom0 capability Joao Martins
2019-02-20 21:09 ` [PATCH RFC 00/39] x86/KVM: Xen HVM guest support Paolo Bonzini
2019-02-21 0:29 ` Ankur Arora
2019-02-21 11:45 ` Joao Martins
2019-02-22 16:59 ` Paolo Bonzini
2019-03-12 17:14 ` Joao Martins
2019-04-08 6:44 ` Juergen Gross
2019-04-08 10:36 ` Joao Martins
2019-04-08 10:42 ` Juergen Gross
2019-04-08 17:31 ` Joao Martins
2019-04-09 0:35 ` Stefano Stabellini
2019-04-10 5:50 ` [Xen-devel] " Ankur Arora
2019-04-10 20:45 ` Stefano Stabellini
2019-04-09 5:04 ` Juergen Gross
2019-04-10 6:55 ` Ankur Arora
2019-04-10 7:14 ` Juergen Gross
2019-02-20 23:39 ` [Xen-devel] " Marek Marczykowski-Górecki
2019-02-21 0:31 ` Ankur Arora
2019-02-21 7:57 ` Juergen Gross
2019-02-21 12:00 ` Joao Martins
2019-02-21 11:55 ` Joao Martins
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