From: Auger Eric <eric.auger@redhat.com> To: Zenghui Yu <yuzenghui@huawei.com>, Alexandru Elisei <alexandru.elisei@arm.com>, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, drjones@redhat.com Cc: andre.przywara@arm.com Subject: Re: [kvm-unit-tests PATCH 10/10] arm64: gic: Use IPI test checking for the LPI tests Date: Mon, 30 Nov 2020 18:48:24 +0100 [thread overview] Message-ID: <23be6c11-fd2e-0d41-df06-91d87cf1a465@redhat.com> (raw) In-Reply-To: <a7069b1d-ef11-7504-644c-8d341fa2aabc@huawei.com> Hi Alexandru, Zenghui On 11/26/20 10:30 AM, Zenghui Yu wrote: > On 2020/11/25 23:51, Alexandru Elisei wrote: >> The reason for the failure is that the test "dev2/eventid=20 now triggers >> an LPI" triggers 2 LPIs, not one. This behavior was present before this >> patch, but it was ignored because check_lpi_stats() wasn't looking at the >> acked array. >> >> I'm not familiar with the ITS so I'm not sure if this is expected, if the >> test is incorrect or if there is something wrong with KVM emulation. > > I think this is expected, or not. > > Before INVALL, the LPI-8195 was already pending but disabled. On > receiving INVALL, VGIC will reload configuration for all LPIs targeting > collection-3 and deliver the now enabled LPI-8195. We'll therefore see > and handle it before sending the following INT (which will set the > LPI-8195 pending again). > >> Did some more testing on an Ampere eMAG (fast out-of-order cores) using >> qemu and kvmtool and Linux v5.8, here's what I found: >> >> - Using qemu and gic.flat built from*master*: error encountered 864 times >> out of 1088 runs. >> - Using qemu: error encountered 852 times out of 1027 runs. >> - Using kvmtool: error encountered 8164 times out of 10602 runs. > > If vcpu-3 hadn't seen and handled LPI-8195 as quickly as possible (e.g., > vcpu-3 hadn't been scheduled), the following INT will set the already > pending LPI-8195 pending again and we'll receive it *once* on vcpu-3. > And we won't see the mentioned failure. > > I think we can just drop the (meaningless and confusing?) INT. Yes I agree with Zenghui, we can remove the INT and just check the pending LPI set while disabled eventually hits Thanks Eric > > > Thanks, > Zenghui >
WARNING: multiple messages have this Message-ID (diff)
From: Auger Eric <eric.auger@redhat.com> To: Zenghui Yu <yuzenghui@huawei.com>, Alexandru Elisei <alexandru.elisei@arm.com>, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, drjones@redhat.com Cc: andre.przywara@arm.com Subject: Re: [kvm-unit-tests PATCH 10/10] arm64: gic: Use IPI test checking for the LPI tests Date: Mon, 30 Nov 2020 18:48:24 +0100 [thread overview] Message-ID: <23be6c11-fd2e-0d41-df06-91d87cf1a465@redhat.com> (raw) In-Reply-To: <a7069b1d-ef11-7504-644c-8d341fa2aabc@huawei.com> Hi Alexandru, Zenghui On 11/26/20 10:30 AM, Zenghui Yu wrote: > On 2020/11/25 23:51, Alexandru Elisei wrote: >> The reason for the failure is that the test "dev2/eventid=20 now triggers >> an LPI" triggers 2 LPIs, not one. This behavior was present before this >> patch, but it was ignored because check_lpi_stats() wasn't looking at the >> acked array. >> >> I'm not familiar with the ITS so I'm not sure if this is expected, if the >> test is incorrect or if there is something wrong with KVM emulation. > > I think this is expected, or not. > > Before INVALL, the LPI-8195 was already pending but disabled. On > receiving INVALL, VGIC will reload configuration for all LPIs targeting > collection-3 and deliver the now enabled LPI-8195. We'll therefore see > and handle it before sending the following INT (which will set the > LPI-8195 pending again). > >> Did some more testing on an Ampere eMAG (fast out-of-order cores) using >> qemu and kvmtool and Linux v5.8, here's what I found: >> >> - Using qemu and gic.flat built from*master*: error encountered 864 times >> out of 1088 runs. >> - Using qemu: error encountered 852 times out of 1027 runs. >> - Using kvmtool: error encountered 8164 times out of 10602 runs. > > If vcpu-3 hadn't seen and handled LPI-8195 as quickly as possible (e.g., > vcpu-3 hadn't been scheduled), the following INT will set the already > pending LPI-8195 pending again and we'll receive it *once* on vcpu-3. > And we won't see the mentioned failure. > > I think we can just drop the (meaningless and confusing?) INT. Yes I agree with Zenghui, we can remove the INT and just check the pending LPI set while disabled eventually hits Thanks Eric > > > Thanks, > Zenghui > _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
next prev parent reply other threads:[~2020-11-30 17:50 UTC|newest] Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-11-25 15:51 [kvm-unit-tests PATCH 00/10] GIC fixes and improvements Alexandru Elisei 2020-11-25 15:51 ` Alexandru Elisei 2020-11-25 15:51 ` [kvm-unit-tests PATCH 01/10] lib: arm/arm64: gicv3: Add missing barrier when sending IPIs Alexandru Elisei 2020-11-25 15:51 ` Alexandru Elisei 2020-12-01 16:37 ` Auger Eric 2020-12-01 16:37 ` Auger Eric 2020-12-01 17:37 ` Alexandru Elisei 2020-12-01 17:37 ` Alexandru Elisei 2020-11-25 15:51 ` [kvm-unit-tests PATCH 02/10] lib: arm/arm64: gicv2: " Alexandru Elisei 2020-11-25 15:51 ` Alexandru Elisei 2020-12-01 16:37 ` Auger Eric 2020-12-01 16:37 ` Auger Eric 2020-11-25 15:51 ` [kvm-unit-tests PATCH 03/10] arm/arm64: gic: Remove memory synchronization from ipi_clear_active_handler() Alexandru Elisei 2020-11-25 15:51 ` Alexandru Elisei 2020-12-01 16:37 ` Auger Eric 2020-12-01 16:37 ` Auger Eric 2020-12-02 14:02 ` Alexandru Elisei 2020-12-02 14:02 ` Alexandru Elisei 2020-12-02 14:14 ` Alexandru Elisei 2020-12-02 14:14 ` Alexandru Elisei 2020-12-03 9:41 ` Auger Eric 2020-12-03 9:41 ` Auger Eric 2020-11-25 15:51 ` [kvm-unit-tests PATCH 04/10] arm/arm64: gic: Remove unnecessary synchronization with stats_reset() Alexandru Elisei 2020-11-25 15:51 ` Alexandru Elisei 2020-12-01 16:48 ` Auger Eric 2020-12-01 16:48 ` Auger Eric 2020-12-02 14:06 ` Alexandru Elisei 2020-12-02 14:06 ` Alexandru Elisei 2020-12-03 13:10 ` Auger Eric 2020-12-03 13:10 ` Auger Eric 2020-11-25 15:51 ` [kvm-unit-tests PATCH 05/10] arm/arm64: gic: Use correct memory ordering for the IPI test Alexandru Elisei 2020-11-25 15:51 ` Alexandru Elisei 2020-12-03 13:10 ` Auger Eric 2020-12-03 13:10 ` Auger Eric 2020-12-03 13:21 ` Alexandru Elisei 2020-12-03 13:21 ` Alexandru Elisei 2020-11-25 15:51 ` [kvm-unit-tests PATCH 06/10] arm/arm64: gic: Check spurious and bad_sender in the active test Alexandru Elisei 2020-11-25 15:51 ` Alexandru Elisei 2020-12-03 13:10 ` Auger Eric 2020-12-03 13:10 ` Auger Eric 2020-11-25 15:51 ` [kvm-unit-tests PATCH 07/10] arm/arm64: gic: Wait for writes to acked or spurious to complete Alexandru Elisei 2020-11-25 15:51 ` Alexandru Elisei 2020-12-03 13:21 ` Auger Eric 2020-12-03 13:21 ` Auger Eric 2020-11-25 15:51 ` [kvm-unit-tests PATCH 08/10] arm/arm64: gic: Split check_acked() into two functions Alexandru Elisei 2020-11-25 15:51 ` Alexandru Elisei 2020-12-03 13:39 ` Auger Eric 2020-12-03 13:39 ` Auger Eric 2020-12-10 14:45 ` Alexandru Elisei 2020-12-10 14:45 ` Alexandru Elisei 2020-12-15 13:58 ` Auger Eric 2020-12-15 13:58 ` Auger Eric 2020-12-16 11:40 ` Alexandru Elisei 2020-12-16 11:40 ` Alexandru Elisei 2020-12-16 12:37 ` Auger Eric 2020-12-16 12:37 ` Auger Eric 2020-11-25 15:51 ` [kvm-unit-tests PATCH 09/10] arm/arm64: gic: Make check_acked() more generic Alexandru Elisei 2020-11-25 15:51 ` Alexandru Elisei 2020-12-03 14:59 ` Auger Eric 2020-12-03 14:59 ` Auger Eric 2020-11-25 15:51 ` [kvm-unit-tests PATCH 10/10] arm64: gic: Use IPI test checking for the LPI tests Alexandru Elisei 2020-11-25 15:51 ` Alexandru Elisei 2020-11-26 9:30 ` Zenghui Yu 2020-11-26 9:30 ` Zenghui Yu 2020-11-27 14:50 ` Alexandru Elisei 2020-11-27 14:50 ` Alexandru Elisei 2020-11-30 13:59 ` Zenghui Yu 2020-11-30 13:59 ` Zenghui Yu 2020-11-30 14:19 ` Alexandru Elisei 2020-11-30 14:19 ` Alexandru Elisei 2020-12-01 15:09 ` Alexandru Elisei 2020-12-01 15:09 ` Alexandru Elisei 2020-11-30 17:48 ` Auger Eric [this message] 2020-11-30 17:48 ` Auger Eric 2020-12-03 14:59 ` Auger Eric 2020-12-03 14:59 ` Auger Eric 2020-12-09 10:29 ` Alexandru Elisei 2020-12-09 10:29 ` Alexandru Elisei
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