Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1265142 > unrolled thread

Re: [PATCH V6 0/6] Fast mmio eventfd fixes

Started by"Michael S. Tsirkin" <mst@redhat.com>
First post2015-11-08 18:20 +0100
Last post2015-11-10 07:30 +0100
Articles 4 — 2 participants

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  Re: [PATCH V6 0/6] Fast mmio eventfd fixes "Michael S. Tsirkin" <mst@redhat.com> - 2015-11-08 18:20 +0100
    Re: [PATCH V6 0/6] Fast mmio eventfd fixes Jason Wang <jasowang@redhat.com> - 2015-11-09 05:40 +0100
      Re: [PATCH V6 0/6] Fast mmio eventfd fixes "Michael S. Tsirkin" <mst@redhat.com> - 2015-11-09 21:20 +0100
        Re: [PATCH V6 0/6] Fast mmio eventfd fixes Jason Wang <jasowang@redhat.com> - 2015-11-10 07:30 +0100

#1265142 — Re: [PATCH V6 0/6] Fast mmio eventfd fixes

From"Michael S. Tsirkin" <mst@redhat.com>
Date2015-11-08 18:20 +0100
SubjectRe: [PATCH V6 0/6] Fast mmio eventfd fixes
Message-ID<qsBNh-30c-33@gated-at.bofh.it>
On Tue, Sep 15, 2015 at 02:41:53PM +0800, Jason Wang wrote:
> Hi:
> 
> This series fixes two issues of fast mmio eventfd:
> 
> 1) A single iodev instance were registerd on two buses: KVM_MMIO_BUS
>    and KVM_FAST_MMIO_BUS. This will cause double in
>    ioeventfd_destructor()
> 2) A zero length iodev on KVM_MMIO_BUS will never be found but
>    kvm_io_bus_cmp(). This will lead e.g the eventfd will be trapped by
>    qemu instead of host.
> 
> 1 is fixed by allocating two instances of iodev and introduce a new
> capability for userspace. 2 is fixed by ignore the actual length if
> the length of iodev is zero in kvm_io_bus_cmp().
> 
> Please review.
> Changes from V5:
> - move patch of explicitly checking for KVM_MMIO_BUS to patch 1 and
>   remove the unnecessary checks
> - even more grammar and typo fixes
> - rabase to kvm.git
> - document KVM_CAP_FAST_MMIO

What's up with userspace using this capability?
Did patches ever get posted?

> 
> Changes from V4:
> - move the location of kvm_assign_ioeventfd() in patch 1 which reduce
>   the change set.
> - commit log typo fixes
> - switch to use kvm_deassign_ioeventfd_id) when fail to register to
>   fast mmio bus
> - change kvm_io_bus_cmp() as Paolo's suggestions
> - introduce a new capability to avoid new userspace crash old kernel
> - add a new patch that only try to register mmio eventfd on fast mmio
>   bus
> 
> Changes from V3:
> 
> - Don't do search on two buses when trying to do write on
>   KVM_MMIO_BUS. This fixes a small regression found by vmexit.flat.
> - Since we don't do search on two buses, change kvm_io_bus_cmp() to
>   let it can find zero length iodevs.
> - Fix the unnecessary lines in tracepoint patch.
> 
> Changes from V2:
> - Tweak styles and comment suggested by Cornelia.
> 
> Changes from v1:
> - change ioeventfd_bus_from_flags() to return KVM_FAST_MMIO_BUS when
>   needed to save lots of unnecessary changes.
> 
> Jason Wang (6):
>   kvm: don't try to register to KVM_FAST_MMIO_BUS for non mmio eventfd
>   kvm: factor out core eventfd assign/deassign logic
>   kvm: fix double free for fast mmio eventfd
>   kvm: fix zero length mmio searching
>   kvm: add tracepoint for fast mmio
>   kvm: add fast mmio capabilitiy
> 
>  Documentation/virtual/kvm/api.txt |   7 ++-
>  arch/x86/kvm/trace.h              |  18 ++++++
>  arch/x86/kvm/vmx.c                |   1 +
>  arch/x86/kvm/x86.c                |   1 +
>  include/uapi/linux/kvm.h          |   1 +
>  virt/kvm/eventfd.c                | 124 ++++++++++++++++++++++----------------
>  virt/kvm/kvm_main.c               |  20 +++++-
>  7 files changed, 118 insertions(+), 54 deletions(-)
> 
> -- 
> 2.1.4
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [next] | [standalone]

#1265339

FromJason Wang <jasowang@redhat.com>
Date2015-11-09 05:40 +0100
Message-ID<qsMpj-1sv-1@gated-at.bofh.it>
In reply to#1265142

On 11/09/2015 01:11 AM, Michael S. Tsirkin wrote:
> On Tue, Sep 15, 2015 at 02:41:53PM +0800, Jason Wang wrote:
>> Hi:
>>
>> This series fixes two issues of fast mmio eventfd:
>>
>> 1) A single iodev instance were registerd on two buses: KVM_MMIO_BUS
>>    and KVM_FAST_MMIO_BUS. This will cause double in
>>    ioeventfd_destructor()
>> 2) A zero length iodev on KVM_MMIO_BUS will never be found but
>>    kvm_io_bus_cmp(). This will lead e.g the eventfd will be trapped by
>>    qemu instead of host.
>>
>> 1 is fixed by allocating two instances of iodev and introduce a new
>> capability for userspace. 2 is fixed by ignore the actual length if
>> the length of iodev is zero in kvm_io_bus_cmp().
>>
>> Please review.
>> Changes from V5:
>> - move patch of explicitly checking for KVM_MMIO_BUS to patch 1 and
>>   remove the unnecessary checks
>> - even more grammar and typo fixes
>> - rabase to kvm.git
>> - document KVM_CAP_FAST_MMIO
> What's up with userspace using this capability?

It was renamed to KVM_CAP_IOEVENTFD_ANY_LENGTH.

> Did patches ever get posted?

See https://lkml.org/lkml/2015/9/28/208

>
>> Changes from V4:
>> - move the location of kvm_assign_ioeventfd() in patch 1 which reduce
>>   the change set.
>> - commit log typo fixes
>> - switch to use kvm_deassign_ioeventfd_id) when fail to register to
>>   fast mmio bus
>> - change kvm_io_bus_cmp() as Paolo's suggestions
>> - introduce a new capability to avoid new userspace crash old kernel
>> - add a new patch that only try to register mmio eventfd on fast mmio
>>   bus
>>
>> Changes from V3:
>>
>> - Don't do search on two buses when trying to do write on
>>   KVM_MMIO_BUS. This fixes a small regression found by vmexit.flat.
>> - Since we don't do search on two buses, change kvm_io_bus_cmp() to
>>   let it can find zero length iodevs.
>> - Fix the unnecessary lines in tracepoint patch.
>>
>> Changes from V2:
>> - Tweak styles and comment suggested by Cornelia.
>>
>> Changes from v1:
>> - change ioeventfd_bus_from_flags() to return KVM_FAST_MMIO_BUS when
>>   needed to save lots of unnecessary changes.
>>
>> Jason Wang (6):
>>   kvm: don't try to register to KVM_FAST_MMIO_BUS for non mmio eventfd
>>   kvm: factor out core eventfd assign/deassign logic
>>   kvm: fix double free for fast mmio eventfd
>>   kvm: fix zero length mmio searching
>>   kvm: add tracepoint for fast mmio
>>   kvm: add fast mmio capabilitiy
>>
>>  Documentation/virtual/kvm/api.txt |   7 ++-
>>  arch/x86/kvm/trace.h              |  18 ++++++
>>  arch/x86/kvm/vmx.c                |   1 +
>>  arch/x86/kvm/x86.c                |   1 +
>>  include/uapi/linux/kvm.h          |   1 +
>>  virt/kvm/eventfd.c                | 124 ++++++++++++++++++++++----------------
>>  virt/kvm/kvm_main.c               |  20 +++++-
>>  7 files changed, 118 insertions(+), 54 deletions(-)
>>
>> -- 
>> 2.1.4
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1265986

From"Michael S. Tsirkin" <mst@redhat.com>
Date2015-11-09 21:20 +0100
Message-ID<qt14Z-2JC-17@gated-at.bofh.it>
In reply to#1265339
On Mon, Nov 09, 2015 at 12:35:45PM +0800, Jason Wang wrote:
> 
> 
> On 11/09/2015 01:11 AM, Michael S. Tsirkin wrote:
> > On Tue, Sep 15, 2015 at 02:41:53PM +0800, Jason Wang wrote:
> >> Hi:
> >>
> >> This series fixes two issues of fast mmio eventfd:
> >>
> >> 1) A single iodev instance were registerd on two buses: KVM_MMIO_BUS
> >>    and KVM_FAST_MMIO_BUS. This will cause double in
> >>    ioeventfd_destructor()
> >> 2) A zero length iodev on KVM_MMIO_BUS will never be found but
> >>    kvm_io_bus_cmp(). This will lead e.g the eventfd will be trapped by
> >>    qemu instead of host.
> >>
> >> 1 is fixed by allocating two instances of iodev and introduce a new
> >> capability for userspace. 2 is fixed by ignore the actual length if
> >> the length of iodev is zero in kvm_io_bus_cmp().
> >>
> >> Please review.
> >> Changes from V5:
> >> - move patch of explicitly checking for KVM_MMIO_BUS to patch 1 and
> >>   remove the unnecessary checks
> >> - even more grammar and typo fixes
> >> - rabase to kvm.git
> >> - document KVM_CAP_FAST_MMIO
> > What's up with userspace using this capability?
> 
> It was renamed to KVM_CAP_IOEVENTFD_ANY_LENGTH.
> 
> > Did patches ever get posted?
> 
> See https://lkml.org/lkml/2015/9/28/208

Talking about userspace here.
QEMU freeze is approaching, it really should
use this to avoid regressions.


> >
> >> Changes from V4:
> >> - move the location of kvm_assign_ioeventfd() in patch 1 which reduce
> >>   the change set.
> >> - commit log typo fixes
> >> - switch to use kvm_deassign_ioeventfd_id) when fail to register to
> >>   fast mmio bus
> >> - change kvm_io_bus_cmp() as Paolo's suggestions
> >> - introduce a new capability to avoid new userspace crash old kernel
> >> - add a new patch that only try to register mmio eventfd on fast mmio
> >>   bus
> >>
> >> Changes from V3:
> >>
> >> - Don't do search on two buses when trying to do write on
> >>   KVM_MMIO_BUS. This fixes a small regression found by vmexit.flat.
> >> - Since we don't do search on two buses, change kvm_io_bus_cmp() to
> >>   let it can find zero length iodevs.
> >> - Fix the unnecessary lines in tracepoint patch.
> >>
> >> Changes from V2:
> >> - Tweak styles and comment suggested by Cornelia.
> >>
> >> Changes from v1:
> >> - change ioeventfd_bus_from_flags() to return KVM_FAST_MMIO_BUS when
> >>   needed to save lots of unnecessary changes.
> >>
> >> Jason Wang (6):
> >>   kvm: don't try to register to KVM_FAST_MMIO_BUS for non mmio eventfd
> >>   kvm: factor out core eventfd assign/deassign logic
> >>   kvm: fix double free for fast mmio eventfd
> >>   kvm: fix zero length mmio searching
> >>   kvm: add tracepoint for fast mmio
> >>   kvm: add fast mmio capabilitiy
> >>
> >>  Documentation/virtual/kvm/api.txt |   7 ++-
> >>  arch/x86/kvm/trace.h              |  18 ++++++
> >>  arch/x86/kvm/vmx.c                |   1 +
> >>  arch/x86/kvm/x86.c                |   1 +
> >>  include/uapi/linux/kvm.h          |   1 +
> >>  virt/kvm/eventfd.c                | 124 ++++++++++++++++++++++----------------
> >>  virt/kvm/kvm_main.c               |  20 +++++-
> >>  7 files changed, 118 insertions(+), 54 deletions(-)
> >>
> >> -- 
> >> 2.1.4
> > --
> > To unsubscribe from this list: send the line "unsubscribe kvm" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1266273

FromJason Wang <jasowang@redhat.com>
Date2015-11-10 07:30 +0100
Message-ID<qtaBj-1ph-3@gated-at.bofh.it>
In reply to#1265986

On 11/10/2015 04:19 AM, Michael S. Tsirkin wrote:
> On Mon, Nov 09, 2015 at 12:35:45PM +0800, Jason Wang wrote:
>> > 
>> > 
>> > On 11/09/2015 01:11 AM, Michael S. Tsirkin wrote:
>>> > > On Tue, Sep 15, 2015 at 02:41:53PM +0800, Jason Wang wrote:
>>>> > >> Hi:
>>>> > >>
>>>> > >> This series fixes two issues of fast mmio eventfd:
>>>> > >>
>>>> > >> 1) A single iodev instance were registerd on two buses: KVM_MMIO_BUS
>>>> > >>    and KVM_FAST_MMIO_BUS. This will cause double in
>>>> > >>    ioeventfd_destructor()
>>>> > >> 2) A zero length iodev on KVM_MMIO_BUS will never be found but
>>>> > >>    kvm_io_bus_cmp(). This will lead e.g the eventfd will be trapped by
>>>> > >>    qemu instead of host.
>>>> > >>
>>>> > >> 1 is fixed by allocating two instances of iodev and introduce a new
>>>> > >> capability for userspace. 2 is fixed by ignore the actual length if
>>>> > >> the length of iodev is zero in kvm_io_bus_cmp().
>>>> > >>
>>>> > >> Please review.
>>>> > >> Changes from V5:
>>>> > >> - move patch of explicitly checking for KVM_MMIO_BUS to patch 1 and
>>>> > >>   remove the unnecessary checks
>>>> > >> - even more grammar and typo fixes
>>>> > >> - rabase to kvm.git
>>>> > >> - document KVM_CAP_FAST_MMIO
>>> > > What's up with userspace using this capability?
>> > 
>> > It was renamed to KVM_CAP_IOEVENTFD_ANY_LENGTH.
>> > 
>>> > > Did patches ever get posted?
>> > 
>> > See https://lkml.org/lkml/2015/9/28/208
> Talking about userspace here.
> QEMU freeze is approaching, it really should
> use this to avoid regressions.
>

The patches were posted at
http://lists.gnu.org/archive/html/qemu-devel/2015-11/msg01276.html

(you were in cc list)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web