Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1312814 > unrolled thread
| Started by | Feng Wu <feng.wu@intel.com> |
|---|---|
| First post | 2016-01-20 03:10 +0100 |
| Last post | 2016-01-25 13:30 +0100 |
| Articles | 9 on this page of 29 — 8 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.
[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
Page 2 of 2 — ← Prev page 1 [2]
| From | Radim Krčmář <rkrcmar@redhat.com> |
|---|---|
| Date | 2016-01-21 17:30 +0100 |
| Subject | Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the interrupt is not single-destination |
| Message-ID | <qTqhs-7Nb-11@gated-at.bofh.it> |
| In reply to | #1312814 |
2016-01-20 09:42+0800, Feng Wu:
> When the interrupt is not single destination any more, we need
> to change back IRTE to remapped mode explicitly.
>
> Signed-off-by: Feng Wu <feng.wu@intel.com>
> ---
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> @@ -10764,8 +10764,17 @@ static int vmx_update_pi_irte(struct kvm *kvm, unsigned int host_irq,
> - if (!kvm_intr_is_single_vcpu(kvm, &irq, &vcpu))
> + if (!kvm_intr_is_single_vcpu(kvm, &irq, &vcpu)) {
> + /*
> + * Make sure the IRTE is in remapped mode if
> + * we don't handle it in posted mode.
> + */
> + pi_set_sn(vcpu_to_pi_desc(vcpu));
What could go wrong if we didn't suppress notifications here?
Thanks.
> + ret = irq_set_vcpu_affinity(host_irq, NULL);
> + pi_clear_sn(vcpu_to_pi_desc(vcpu));
> +
> continue;
> + }
[toc] | [prev] | [next] | [standalone]
| From | "Wu, Feng" <feng.wu@intel.com> |
|---|---|
| Date | 2016-01-22 02:50 +0100 |
| Subject | RE: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the interrupt is not single-destination |
| Message-ID | <qTz1o-5gH-7@gated-at.bofh.it> |
| In reply to | #1314330 |
> -----Original Message-----
> From: Radim Krčmář [mailto:rkrcmar@redhat.com]
> Sent: Friday, January 22, 2016 12:20 AM
> To: Wu, Feng <feng.wu@intel.com>
> Cc: pbonzini@redhat.com; linux-kernel@vger.kernel.org;
> kvm@vger.kernel.org
> Subject: Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the
> interrupt is not single-destination
>
> 2016-01-20 09:42+0800, Feng Wu:
> > When the interrupt is not single destination any more, we need
> > to change back IRTE to remapped mode explicitly.
> >
> > Signed-off-by: Feng Wu <feng.wu@intel.com>
> > ---
> > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> > @@ -10764,8 +10764,17 @@ static int vmx_update_pi_irte(struct kvm
> *kvm, unsigned int host_irq,
> > - if (!kvm_intr_is_single_vcpu(kvm, &irq, &vcpu))
> > + if (!kvm_intr_is_single_vcpu(kvm, &irq, &vcpu)) {
> > + /*
> > + * Make sure the IRTE is in remapped mode if
> > + * we don't handle it in posted mode.
> > + */
> > + pi_set_sn(vcpu_to_pi_desc(vcpu));
>
> What could go wrong if we didn't suppress notifications here?
This is a good question. I also thought about this before, but after
thinking it a bit more, seems we don't need to do this.
If we don't do this, the in-flight interrupts will continue to be
delivered in PI mode while we are changing it to remapped
mode in IRTE. Even if we do this, the in-flight interrupts are
also delivered in PI mode before setting 'SN' anyway, so seems
we really don't need this, what is your opinion?
Thanks,
Feng
Thanks,
Feng
>
> Thanks.
>
> > + ret = irq_set_vcpu_affinity(host_irq, NULL);
> > + pi_clear_sn(vcpu_to_pi_desc(vcpu));
> > +
> > continue;
> > + }
[toc] | [prev] | [next] | [standalone]
| From | Radim Krcmár <rkrcmar@redhat.com> |
|---|---|
| Date | 2016-01-22 14:10 +0100 |
| Subject | Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the interrupt is not single-destination |
| Message-ID | <qTJDs-4tt-11@gated-at.bofh.it> |
| In reply to | #1314692 |
2016-01-22 01:49+0000, Wu, Feng:
>> From: Radim Krčmář [mailto:rkrcmar@redhat.com]
>> 2016-01-20 09:42+0800, Feng Wu:
>> > - if (!kvm_intr_is_single_vcpu(kvm, &irq, &vcpu))
>> > + if (!kvm_intr_is_single_vcpu(kvm, &irq, &vcpu)) {
>> > + /*
>> > + * Make sure the IRTE is in remapped mode if
>> > + * we don't handle it in posted mode.
>> > + */
>> > + pi_set_sn(vcpu_to_pi_desc(vcpu));
>>
>> What could go wrong if we didn't suppress notifications here?
>
> This is a good question. I also thought about this before, but after
> thinking it a bit more, seems we don't need to do this.
> If we don't do this, the in-flight interrupts will continue to be
> delivered in PI mode while we are changing it to remapped
> mode in IRTE. Even if we do this, the in-flight interrupts are
> also delivered in PI mode before setting 'SN' anyway, so seems
> we really don't need this, what is your opinion?
I'd remove it.
[toc] | [prev] | [next] | [standalone]
| From | "Wu, Feng" <feng.wu@intel.com> |
|---|---|
| Date | 2016-01-25 13:30 +0100 |
| Subject | RE: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the interrupt is not single-destination |
| Message-ID | <qUOro-3Og-21@gated-at.bofh.it> |
| In reply to | #1314969 |
> -----Original Message----- > From: Paolo Bonzini [mailto:paolo.bonzini@gmail.com] On Behalf Of Paolo > Bonzini > Sent: Monday, January 25, 2016 8:23 PM > To: Radim Krcmár <rkrcmar@redhat.com>; Wu, Feng <feng.wu@intel.com> > Cc: linux-kernel@vger.kernel.org; kvm@vger.kernel.org > Subject: Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the > interrupt is not single-destination > > > > On 22/01/2016 14:05, Radim Krcmár wrote: > > > This is a good question. I also thought about this before, but after > > > thinking it a bit more, seems we don't need to do this. > > > If we don't do this, the in-flight interrupts will continue to be > > > delivered in PI mode while we are changing it to remapped > > > mode in IRTE. Even if we do this, the in-flight interrupts are > > > also delivered in PI mode before setting 'SN' anyway, so seems > > > we really don't need this, what is your opinion? > > I'd remove it. > > 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. Thanks, Feng > > If so, no need to send v5, I'll add it back. > > Paolo
[toc] | [prev] | [next] | [standalone]
| From | Paolo Bonzini <pbonzini@redhat.com> |
|---|---|
| Date | 2016-01-25 13:40 +0100 |
| Subject | Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the interrupt is not single-destination |
| Message-ID | <qUOB3-3Tm-5@gated-at.bofh.it> |
| In reply to | #1316619 |
On 25/01/2016 13:26, Wu, Feng wrote: >> > 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. Great, I hadn't noticed that patch. Thanks. Paolo
[toc] | [prev] | [next] | [standalone]
| From | "Wu, Feng" <feng.wu@intel.com> |
|---|---|
| Date | 2016-01-25 13:50 +0100 |
| Subject | RE: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the interrupt is not single-destination |
| Message-ID | <qUOKM-3WU-51@gated-at.bofh.it> |
| In reply to | #1316630 |
> -----Original Message----- > From: Paolo Bonzini [mailto:pbonzini@redhat.com] > Sent: Monday, January 25, 2016 8:39 PM > To: Wu, Feng <feng.wu@intel.com>; Radim Krcmár <rkrcmar@redhat.com> > Cc: linux-kernel@vger.kernel.org; kvm@vger.kernel.org > Subject: Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the > interrupt is not single-destination > > > > On 25/01/2016 13:26, Wu, Feng wrote: > >> > 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. > > Great, I hadn't noticed that patch. Thanks. I might forget to cc KVM mailing list, sorry for that! Thanks, Feng > > Paolo
[toc] | [prev] | [next] | [standalone]
| From | Radim Krcmár <rkrcmar@redhat.com> |
|---|---|
| Date | 2016-01-25 15:10 +0100 |
| Subject | Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the interrupt is not single-destination |
| Message-ID | <qUQ09-54G-9@gated-at.bofh.it> |
| In reply to | #1316619 |
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 ...
[toc] | [prev] | [next] | [standalone]
| From | "Wu, Feng" <feng.wu@intel.com> |
|---|---|
| Date | 2016-01-26 02:00 +0100 |
| Subject | RE: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the interrupt is not single-destination |
| Message-ID | <qV09c-3JU-9@gated-at.bofh.it> |
| In reply to | #1316729 |
> -----Original Message----- > From: Radim Krcmár [mailto:rkrcmar@redhat.com] > Sent: Monday, January 25, 2016 10:06 PM > To: Wu, Feng <feng.wu@intel.com> > Cc: Paolo Bonzini <pbonzini@redhat.com>; linux-kernel@vger.kernel.org; > kvm@vger.kernel.org > Subject: Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the > interrupt is not single-destination > > 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. Yes, like the comments in the commit, we should atomically update the IRTE in PI case (PI -> non-PI, non-PI -> PI), without which, it cannot guarantee the correctness, since 'pda' is not within 64 bits, like Radim pointed out above. Thanks, Feng > > IRTE invalidation seems important in VT-d ...
[toc] | [prev] | [next] | [standalone]
| From | Paolo Bonzini <pbonzini@redhat.com> |
|---|---|
| Date | 2016-01-25 13:30 +0100 |
| Subject | Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the interrupt is not single-destination |
| Message-ID | <qUOro-3Og-23@gated-at.bofh.it> |
| In reply to | #1314969 |
On 22/01/2016 14:05, Radim Krcmár wrote: > > This is a good question. I also thought about this before, but after > > thinking it a bit more, seems we don't need to do this. > > If we don't do this, the in-flight interrupts will continue to be > > delivered in PI mode while we are changing it to remapped > > mode in IRTE. Even if we do this, the in-flight interrupts are > > also delivered in PI mode before setting 'SN' anyway, so seems > > we really don't need this, what is your opinion? > I'd remove it. It may be necessary because IRTE writes (128 bits) are not atomic. If so, no need to send v5, I'll add it back. Paolo
[toc] | [prev] | [standalone]
Page 2 of 2 — ← Prev page 1 [2]
Back to top | Article view | linux.kernel
csiph-web