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From: Marc Zyngier <maz@kernel.org>
To: Reiji Watanabe <reijiw@google.com>
Cc: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
	kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 4/4] KVM: arm64: selftests: Add a test case for KVM_GUESTDBG_SINGLESTEP
Date: Mon, 19 Sep 2022 10:36:43 +0100	[thread overview]
Message-ID: <87bkrbln84.wl-maz@kernel.org> (raw)
In-Reply-To: <20220917010600.532642-5-reijiw@google.com>

On Sat, 17 Sep 2022 02:06:00 +0100,
Reiji Watanabe <reijiw@google.com> wrote:
> 
> Add a test case for KVM_GUESTDBG_SINGLESTEP to the debug-exceptions test.
> The test enables single-step execution from userspace, and check if the
> exit to userspace occurs for each instruction that is stepped.
> Set the default number of the test iterations to a number of iterations
> sufficient to always reproduce the problem that the previous patch fixes
> on an Ampere Altra machine.

A possibly more aggressive version of this test would be to force a
(short lived) timer to fire on the same CPU, forcing an exit. This
should hopefully result in a more predictable way to trigger the
issue. But that's a reasonable test as a start.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <maz@kernel.org>
To: Reiji Watanabe <reijiw@google.com>
Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	James Morse <james.morse@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Ricardo Koller <ricarkol@google.com>,
	Oliver Upton <oliver.upton@linux.dev>,
	Jing Zhang <jingzhangos@google.com>,
	Raghavendra Rao Anata <rananta@google.com>
Subject: Re: [PATCH v2 4/4] KVM: arm64: selftests: Add a test case for KVM_GUESTDBG_SINGLESTEP
Date: Mon, 19 Sep 2022 10:36:43 +0100	[thread overview]
Message-ID: <87bkrbln84.wl-maz@kernel.org> (raw)
In-Reply-To: <20220917010600.532642-5-reijiw@google.com>

On Sat, 17 Sep 2022 02:06:00 +0100,
Reiji Watanabe <reijiw@google.com> wrote:
> 
> Add a test case for KVM_GUESTDBG_SINGLESTEP to the debug-exceptions test.
> The test enables single-step execution from userspace, and check if the
> exit to userspace occurs for each instruction that is stepped.
> Set the default number of the test iterations to a number of iterations
> sufficient to always reproduce the problem that the previous patch fixes
> on an Ampere Altra machine.

A possibly more aggressive version of this test would be to force a
(short lived) timer to fire on the same CPU, forcing an exit. This
should hopefully result in a more predictable way to trigger the
issue. But that's a reasonable test as a start.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <maz@kernel.org>
To: Reiji Watanabe <reijiw@google.com>
Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	James Morse <james.morse@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Ricardo Koller <ricarkol@google.com>,
	Oliver Upton <oliver.upton@linux.dev>,
	Jing Zhang <jingzhangos@google.com>,
	Raghavendra Rao Anata <rananta@google.com>
Subject: Re: [PATCH v2 4/4] KVM: arm64: selftests: Add a test case for KVM_GUESTDBG_SINGLESTEP
Date: Mon, 19 Sep 2022 10:36:43 +0100	[thread overview]
Message-ID: <87bkrbln84.wl-maz@kernel.org> (raw)
In-Reply-To: <20220917010600.532642-5-reijiw@google.com>

On Sat, 17 Sep 2022 02:06:00 +0100,
Reiji Watanabe <reijiw@google.com> wrote:
> 
> Add a test case for KVM_GUESTDBG_SINGLESTEP to the debug-exceptions test.
> The test enables single-step execution from userspace, and check if the
> exit to userspace occurs for each instruction that is stepped.
> Set the default number of the test iterations to a number of iterations
> sufficient to always reproduce the problem that the previous patch fixes
> on an Ampere Altra machine.

A possibly more aggressive version of this test would be to force a
(short lived) timer to fire on the same CPU, forcing an exit. This
should hopefully result in a more predictable way to trigger the
issue. But that's a reasonable test as a start.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.

  reply	other threads:[~2022-09-19  9:36 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-17  1:05 [PATCH v2 0/4] KVM: arm64: Fix bugs of single-step execution enabled by userspace Reiji Watanabe
2022-09-17  1:05 ` Reiji Watanabe
2022-09-17  1:05 ` Reiji Watanabe
2022-09-17  1:05 ` [PATCH v2 1/4] KVM: arm64: Preserve PSTATE.SS for the guest while single-step is enabled Reiji Watanabe
2022-09-17  1:05   ` Reiji Watanabe
2022-09-17  1:05   ` Reiji Watanabe
2022-09-17  1:05 ` [PATCH v2 2/4] KVM: arm64: Clear PSTATE.SS when the Software Step state was Active-pending Reiji Watanabe
2022-09-17  1:05   ` Reiji Watanabe
2022-09-17  1:05   ` Reiji Watanabe
2022-09-17  1:05 ` [PATCH v2 3/4] KVM: arm64: selftests: Refactor debug-exceptions to make it amenable to new test cases Reiji Watanabe
2022-09-17  1:05   ` Reiji Watanabe
2022-09-17  1:05   ` Reiji Watanabe
2022-09-17  1:06 ` [PATCH v2 4/4] KVM: arm64: selftests: Add a test case for KVM_GUESTDBG_SINGLESTEP Reiji Watanabe
2022-09-17  1:06   ` Reiji Watanabe
2022-09-17  1:06   ` Reiji Watanabe
2022-09-19  9:36   ` Marc Zyngier [this message]
2022-09-19  9:36     ` Marc Zyngier
2022-09-19  9:36     ` Marc Zyngier
2022-09-20  2:13     ` Reiji Watanabe
2022-09-20  2:13       ` Reiji Watanabe
2022-09-20  2:13       ` Reiji Watanabe
2022-09-19 10:04 ` [PATCH v2 0/4] KVM: arm64: Fix bugs of single-step execution enabled by userspace Marc Zyngier
2022-09-19 10:04   ` Marc Zyngier
2022-09-19 10:04   ` Marc Zyngier

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