From: Auger Eric <eric.auger@redhat.com> To: Marc Zyngier <marc.zyngier@arm.com>, Peter Maydell <peter.maydell@linaro.org> Cc: Andrew Jones <drjones@redhat.com>, kvm-devel <kvm@vger.kernel.org>, "prasun.kapoor" <Prasun.Kapoor@cavium.com>, Vijaya Kumar K <vijayak@caviumnetworks.com>, Andre Przywara <andre.przywara@arm.com>, Juan Quintela <quintela@redhat.com>, "Dr. David Alan Gilbert" <dgilbert@redhat.com>, "Kumar, Vijaya" <Vijaya.Kumar@cavium.com>, Christoffer Dall <christoffer.dall@linaro.org>, Paolo Bonzini <pbonzini@redhat.com>, "kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>, arm-mail-list <linux-arm-kernel@lists.infradead.org>, eric.auger.pro@gmail.com Subject: Re: [PATCH v4 08/22] KVM: arm64: ITS: Implement vgic_mmio_uaccess_write_its_iidr Date: Tue, 11 Apr 2017 12:56:28 +0200 [thread overview] Message-ID: <5a908f96-86e9-6ce6-7680-a08e2968bf7e@redhat.com> (raw) In-Reply-To: <5b2a8ed0-bfc7-852b-07d8-8474aef25b2a@arm.com> Hi, On 11/04/2017 12:29, Marc Zyngier wrote: > On 11/04/17 11:16, Peter Maydell wrote: >> On 11 April 2017 at 11:08, Auger Eric <eric.auger@redhat.com> wrote: >>> On 11/04/2017 12:05, Marc Zyngier wrote: >>>> On 10/04/17 16:17, Auger Eric wrote: >>>>> A (v1) -> B (v1 & v2): migration OK >>>>> B (v1 & v2) -> C (v1): migration NOK >>>> >>>> So what does IIDR report on B once the A->B migration has taken place? >>>> Does it report v2? >>> >>> yes that was the plan >> >> Hmm, the IIDR value shouldn't change across a migration I think. >> It's guest visible so the guest should see it still the same >> value even after migration. > > That's my worry. But we then have a problem when this VM migrates again. > How does userspace find out which ABI to use then? Today the userspace just conveys the information from source kernel to destination kernel through the IIDR value. This allows the destination kernel to know what was the table layout used during the migration. If we report the source ABI revision value on the destination, what is the strategy we should adopt: - limit the features to those that will be migratable through this ABI - allow the functionalities (GICv4 for instance) but reject save? Thanks Eric > > Thanks, > > M. >
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From: eric.auger@redhat.com (Auger Eric) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v4 08/22] KVM: arm64: ITS: Implement vgic_mmio_uaccess_write_its_iidr Date: Tue, 11 Apr 2017 12:56:28 +0200 [thread overview] Message-ID: <5a908f96-86e9-6ce6-7680-a08e2968bf7e@redhat.com> (raw) In-Reply-To: <5b2a8ed0-bfc7-852b-07d8-8474aef25b2a@arm.com> Hi, On 11/04/2017 12:29, Marc Zyngier wrote: > On 11/04/17 11:16, Peter Maydell wrote: >> On 11 April 2017 at 11:08, Auger Eric <eric.auger@redhat.com> wrote: >>> On 11/04/2017 12:05, Marc Zyngier wrote: >>>> On 10/04/17 16:17, Auger Eric wrote: >>>>> A (v1) -> B (v1 & v2): migration OK >>>>> B (v1 & v2) -> C (v1): migration NOK >>>> >>>> So what does IIDR report on B once the A->B migration has taken place? >>>> Does it report v2? >>> >>> yes that was the plan >> >> Hmm, the IIDR value shouldn't change across a migration I think. >> It's guest visible so the guest should see it still the same >> value even after migration. > > That's my worry. But we then have a problem when this VM migrates again. > How does userspace find out which ABI to use then? Today the userspace just conveys the information from source kernel to destination kernel through the IIDR value. This allows the destination kernel to know what was the table layout used during the migration. If we report the source ABI revision value on the destination, what is the strategy we should adopt: - limit the features to those that will be migratable through this ABI - allow the functionalities (GICv4 for instance) but reject save? Thanks Eric > > Thanks, > > M. >
next prev parent reply other threads:[~2017-04-11 10:56 UTC|newest] Thread overview: 144+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-03-27 9:30 [PATCH v4 00/22] vITS save/restore Eric Auger 2017-03-27 9:30 ` Eric Auger 2017-03-27 9:30 ` [PATCH v4 01/22] KVM: arm/arm64: Add vITS save/restore API documentation Eric Auger 2017-03-27 9:30 ` Eric Auger 2017-04-08 10:03 ` Marc Zyngier 2017-04-08 10:03 ` Marc Zyngier 2017-04-08 13:15 ` Christoffer Dall 2017-04-08 13:15 ` Christoffer Dall 2017-04-08 17:31 ` Marc Zyngier 2017-04-08 17:31 ` Marc Zyngier 2017-04-10 10:18 ` Auger Eric 2017-04-10 10:18 ` Auger Eric 2017-04-10 10:42 ` Marc Zyngier 2017-04-10 10:42 ` Marc Zyngier 2017-04-08 18:17 ` Christoffer Dall 2017-04-08 18:17 ` Christoffer Dall 2017-04-10 14:26 ` Auger Eric 2017-04-10 14:26 ` Auger Eric 2017-04-21 9:12 ` Christoffer Dall 2017-04-21 9:12 ` Christoffer Dall 2017-03-27 9:30 ` [PATCH v4 02/22] KVM: arm/arm64: rename itte into ite Eric Auger 2017-03-27 9:30 ` Eric Auger 2017-04-08 10:04 ` Marc Zyngier 2017-04-08 10:04 ` Marc Zyngier 2017-03-27 9:30 ` [PATCH v4 03/22] arm/arm64: vgic: turn vgic_find_mmio_region into public Eric Auger 2017-03-27 9:30 ` Eric Auger 2017-04-08 10:06 ` Marc Zyngier 2017-04-08 10:06 ` Marc Zyngier 2017-04-08 10:06 ` Marc Zyngier 2017-03-27 9:30 ` [PATCH v4 04/22] KVM: arm64: ITS: KVM_DEV_ARM_VGIC_GRP_ITS_REGS group Eric Auger 2017-03-27 9:30 ` Eric Auger 2017-04-08 10:07 ` Marc Zyngier 2017-04-08 10:07 ` Marc Zyngier 2017-03-27 9:30 ` [PATCH v4 05/22] KVM: arm/arm64: vgic: expose (un)lock_all_vcpus Eric Auger 2017-03-27 9:30 ` Eric Auger 2017-04-08 10:09 ` Marc Zyngier 2017-04-08 10:09 ` Marc Zyngier 2017-03-27 9:30 ` [PATCH v4 06/22] KVM: arm64: ITS: Implement vgic_its_has_attr_regs and attr_regs_access Eric Auger 2017-03-27 9:30 ` Eric Auger 2017-04-08 10:24 ` Marc Zyngier 2017-04-08 10:24 ` Marc Zyngier 2017-04-08 10:24 ` Marc Zyngier 2017-03-27 9:30 ` [PATCH v4 07/22] KVM: arm64: ITS: Implement vgic_mmio_uaccess_write_its_creadr Eric Auger 2017-03-27 9:30 ` Eric Auger 2017-04-08 10:36 ` Marc Zyngier 2017-04-08 10:36 ` Marc Zyngier 2017-04-08 10:36 ` Marc Zyngier 2017-03-27 9:30 ` [PATCH v4 08/22] KVM: arm64: ITS: Implement vgic_mmio_uaccess_write_its_iidr Eric Auger 2017-03-27 9:30 ` Eric Auger 2017-04-08 10:42 ` Marc Zyngier 2017-04-08 10:42 ` Marc Zyngier 2017-04-08 10:42 ` Marc Zyngier 2017-04-10 14:32 ` Auger Eric 2017-04-10 14:32 ` Auger Eric 2017-04-10 14:57 ` Marc Zyngier 2017-04-10 14:57 ` Marc Zyngier 2017-04-10 15:07 ` Peter Maydell 2017-04-10 15:07 ` Peter Maydell 2017-04-10 15:17 ` Auger Eric 2017-04-10 15:17 ` Auger Eric 2017-04-11 10:05 ` Marc Zyngier 2017-04-11 10:05 ` Marc Zyngier 2017-04-11 10:08 ` Auger Eric 2017-04-11 10:08 ` Auger Eric 2017-04-11 10:16 ` Peter Maydell 2017-04-11 10:16 ` Peter Maydell 2017-04-11 10:29 ` Marc Zyngier 2017-04-11 10:29 ` Marc Zyngier 2017-04-11 10:43 ` Peter Maydell 2017-04-11 10:43 ` Peter Maydell 2017-04-11 10:56 ` Auger Eric [this message] 2017-04-11 10:56 ` Auger Eric 2017-03-27 9:30 ` [PATCH v4 09/22] KVM: arm64: ITS: Report the ITE size in GITS_TYPER Eric Auger 2017-03-27 9:30 ` Eric Auger 2017-04-08 17:42 ` Marc Zyngier 2017-04-08 17:42 ` Marc Zyngier 2017-03-27 9:31 ` [PATCH v4 10/22] KVM: arm64: ITS: Interpret MAPD Size field and check related errors Eric Auger 2017-03-27 9:31 ` Eric Auger 2017-04-08 17:59 ` Marc Zyngier 2017-04-08 17:59 ` Marc Zyngier 2017-04-08 17:59 ` Marc Zyngier 2017-03-27 9:31 ` [PATCH v4 11/22] KVM: arm64: ITS: Interpret MAPD ITT_addr field Eric Auger 2017-03-27 9:31 ` Eric Auger 2017-04-08 18:58 ` Marc Zyngier 2017-04-08 18:58 ` Marc Zyngier 2017-04-08 18:58 ` Marc Zyngier 2017-03-27 9:31 ` [PATCH v4 12/22] KVM: arm64: ITS: Check the device id matches TYPER DEVBITS range Eric Auger 2017-03-27 9:31 ` Eric Auger 2017-03-27 9:31 ` [PATCH v4 13/22] KVM: arm64: ITS: KVM_DEV_ARM_VGIC_GRP_ITS_TABLES group Eric Auger 2017-03-27 9:31 ` Eric Auger 2017-03-27 15:04 ` kbuild test robot 2017-03-27 15:04 ` kbuild test robot 2017-03-27 18:29 ` Auger Eric 2017-03-27 18:29 ` Auger Eric 2017-03-30 2:21 ` [kbuild-all] " Ye Xiaolong 2017-03-30 2:21 ` Ye Xiaolong 2017-03-30 6:46 ` Auger Eric 2017-03-30 6:46 ` Auger Eric 2017-03-30 7:29 ` Ye Xiaolong 2017-03-30 7:29 ` Ye Xiaolong 2017-03-30 8:29 ` Auger Eric 2017-03-30 8:29 ` Auger Eric 2017-04-09 10:09 ` Marc Zyngier 2017-04-09 10:09 ` Marc Zyngier 2017-03-27 9:31 ` [PATCH v4 14/22] KVM: arm64: ITS: vgic_its_alloc_ite/device Eric Auger 2017-03-27 9:31 ` Eric Auger 2017-04-09 10:13 ` Marc Zyngier 2017-04-09 10:13 ` Marc Zyngier 2017-03-27 9:31 ` [PATCH v4 15/22] KVM: arm64: ITS: Sort the device and ITE lists Eric Auger 2017-03-27 9:31 ` Eric Auger 2017-04-09 10:18 ` Marc Zyngier 2017-04-09 10:18 ` Marc Zyngier 2017-03-27 9:31 ` [PATCH v4 16/22] KVM: expose next_segment() Eric Auger 2017-03-27 9:31 ` Eric Auger 2017-03-27 9:31 ` [PATCH v4 17/22] KVM: arm64: ITS: Add infrastructure for table lookup Eric Auger 2017-03-27 9:31 ` Eric Auger 2017-04-09 10:36 ` Marc Zyngier 2017-04-09 10:36 ` Marc Zyngier 2017-03-27 9:31 ` [PATCH v4 18/22] KVM: arm64: ITS: Collection table save/restore Eric Auger 2017-03-27 9:31 ` Eric Auger 2017-04-10 9:55 ` Marc Zyngier 2017-04-10 9:55 ` Marc Zyngier 2017-04-11 9:57 ` Auger Eric 2017-04-11 9:57 ` Auger Eric 2017-04-11 10:03 ` Marc Zyngier 2017-04-11 10:03 ` Marc Zyngier 2017-03-27 9:31 ` [PATCH v4 19/22] KVM: arm64: ITS: vgic_its_check_id returns the entry's GPA Eric Auger 2017-03-27 9:31 ` Eric Auger 2017-03-27 9:31 ` [PATCH v4 20/22] KVM: arm64: ITS: ITT flush and restore Eric Auger 2017-03-27 9:31 ` Eric Auger 2017-04-10 12:39 ` Marc Zyngier 2017-04-10 12:39 ` Marc Zyngier 2017-04-11 10:19 ` Auger Eric 2017-04-11 10:19 ` Auger Eric 2017-03-27 9:31 ` [PATCH v4 21/22] KVM: arm64: ITS: Device table save/restore Eric Auger 2017-03-27 9:31 ` Eric Auger 2017-04-10 12:42 ` Marc Zyngier 2017-04-10 12:42 ` Marc Zyngier 2017-03-27 9:31 ` [PATCH v4 22/22] KVM: arm64: ITS: Pending " Eric Auger 2017-03-27 9:31 ` Eric Auger 2017-04-10 12:50 ` Marc Zyngier 2017-04-10 12:50 ` Marc Zyngier 2017-04-10 12:54 ` [PATCH v4 00/22] vITS save/restore Marc Zyngier 2017-04-10 12:54 ` Marc Zyngier
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