Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the interrupt is not single-destination

From	Radim Krcmár <rkrcmar@redhat.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the interrupt is not single-destination
Date	2016-01-25 15:10 +0100
Message-ID	<qUQ09-54G-9@gated-at.bofh.it> (permalink)
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2016-01-25 12:26+0000, Wu, Feng:
>> From: Paolo Bonzini [mailto:paolo.bonzini@gmail.com] On Behalf Of Paolo
>> It may be necessary because IRTE writes (128 bits) are not atomic.
> 
> IRTE is updated atomically, I added the patch to support this. Please
> refer to 344cb4e0b6f3a0dbef0643eacb4946338eb228c0.

I also think that SN bit is not affected by atomicity: if the IRTE could
have been read half-updated while changing from posted to non-posted,
then it wouldn't point to the correct PID, because its address is not
within 64 bits, so the SN bit wouldn't matter.

IRTE invalidation seems important in VT-d ...

Thread

[PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the interrupt is not single-destination Feng Wu <feng.wu@intel.com> - 2016-01-20 03:10 +0100
  Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination Yang Zhang <yang.zhang.wz@gmail.com> - 2016-01-21 04:10 +0100
    RE: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination "Wu, Feng" <feng.wu@intel.com> - 2016-01-21 04:20 +0100
      Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination Yang Zhang <yang.zhang.wz@gmail.com> - 2016-01-21 04:40 +0100
        RE: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination "Wu, Feng" <feng.wu@intel.com> - 2016-01-21 05:50 +0100
          RE: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination "Tian, Kevin" <kevin.tian@intel.com> - 2016-01-21 06:00 +0100
          Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination Yang Zhang <yang.zhang.wz@gmail.com> - 2016-01-21 06:00 +0100
            RE: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination "Wu, Feng" <feng.wu@intel.com> - 2016-01-21 06:10 +0100
              Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination Yang Zhang <yang.zhang.wz@gmail.com> - 2016-01-21 06:40 +0100
                Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination Yang Zhang <yang.zhang.wz@gmail.com> - 2016-01-21 06:50 +0100
                Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination "rkrcmar@redhat.com" <rkrcmar@redhat.com> - 2016-01-21 17:40 +0100
                Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination Yang Zhang <yang.zhang.wz@gmail.com> - 2016-01-22 03:10 +0100
                Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination "rkrcmar@redhat.com" <rkrcmar@redhat.com> - 2016-01-22 14:40 +0100
                Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination Yang Zhang <yang.zhang.wz@gmail.com> - 2016-01-25 03:00 +0100
                Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination "rkrcmar@redhat.com" <rkrcmar@redhat.com> - 2016-01-25 15:00 +0100
                Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination Yang Zhang <yang.zhang.wz@gmail.com> - 2016-01-26 02:50 +0100
                Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination "rkrcmar@redhat.com" <rkrcmar@redhat.com> - 2016-01-26 19:30 +0100
                Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination Yang Zhang <yang.zhang.wz@gmail.com> - 2016-01-27 03:10 +0100
                Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination "rkrcmar@redhat.com" <rkrcmar@redhat.com> - 2016-01-27 16:10 +0100
                RE: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination "Wu, Feng" <feng.wu@intel.com> - 2016-01-21 06:50 +0100
  Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination Radim Krčmář <rkrcmar@redhat.com> - 2016-01-21 17:30 +0100
    RE: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination "Wu, Feng" <feng.wu@intel.com> - 2016-01-22 02:50 +0100
      Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination Radim Krcmár <rkrcmar@redhat.com> - 2016-01-22 14:10 +0100
        RE: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination "Wu, Feng" <feng.wu@intel.com> - 2016-01-25 13:30 +0100
          Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination Paolo Bonzini <pbonzini@redhat.com> - 2016-01-25 13:40 +0100
            RE: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination "Wu, Feng" <feng.wu@intel.com> - 2016-01-25 13:50 +0100
          Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination Radim Krcmár <rkrcmar@redhat.com> - 2016-01-25 15:10 +0100
            RE: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination "Wu, Feng" <feng.wu@intel.com> - 2016-01-26 02:00 +0100
        Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the  interrupt is not single-destination Paolo Bonzini <pbonzini@redhat.com> - 2016-01-25 13:30 +0100

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