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From: puranjay@kernel.org
To: "Arnd Bergmann" <arnd@arndb.de>, "Marc Zyngier" <maz@kernel.org>,
	"Arnd Bergmann" <arnd@kernel.org>,
	"Alex Bennée" <alex.bennee@linaro.org>,
	kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
	"Sumit Garg" <sumit.garg@linaro.org>
Cc: puranjay12@gmail.com
Subject: Supporting KVM_GUESTDBG_BLOCKIRQ or something similar on ARM64
Date: Mon, 28 Oct 2024 10:53:34 +0000	[thread overview]
Message-ID: <mb61p4j4wwlap.fsf@kernel.org> (raw)

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Hi Everyone,

I work on the BPF JIT for arm64 and regularly use Qemu with gdb for
debugging by single stepping parts of the code. I realized that whenever
I enable KVM, single stepping doesn't work as expected and it lands in an
interrupt handler.

It always worked for me on x86 so I looked in the source code and found
that x86 supports KVM_GUESTDBG_BLOCKIRQ that blocks IRQs when single
stepping.

I assume that arm64 doesn't support KVM_GUESTDBG_BLOCKIRQ because it is
not trivial to implement this on arm64 due to some architectural
limitations? There was a patch [1] posted in 2022 to solve this issue
but it was not merged.

Let's start a discussion about what needs to be done to support this on
arm64.

Thanks,
Puranjay

[1] https://lore.kernel.org/lkml/20221219102452.2860088-2-sumit.garg@linaro.org/

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             reply	other threads:[~2024-10-28 12:00 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-28 10:53 puranjay [this message]
2024-10-28 11:23 ` Supporting KVM_GUESTDBG_BLOCKIRQ or something similar on ARM64 Marc Zyngier
2024-10-29  8:52   ` Ard Biesheuvel
2024-10-29  9:53     ` Marc Zyngier
2024-10-29 10:00       ` Ard Biesheuvel
2024-10-29 13:57         ` Mark Rutland
2024-10-29 15:36           ` Marc Zyngier

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