From: Tom Rini <trini@konsulko.com>
To: Simon Glass <sjg@chromium.org>
Cc: U-Boot Mailing List <u-boot@lists.denx.de>,
Bin Meng <bmeng.cn@gmail.com>,
Andrew Goodbody <andrew.goodbody@linaro.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Angelo Dureghello <angelo@kernel-space.org>,
Love Kumar <love.kumar@amd.com>,
Mattijs Korpershoek <mkorpershoek@baylibre.com>,
Philip Oberfichtner <pro@denx.de>,
Stephen Warren <swarren@nvidia.com>,
Stephen Warren <swarren@wwwdotorg.org>,
qemu-devel@nongnu.org
Subject: Re: [PATCH v2 00/28] x86: Improve operation under QEMU
Date: Sun, 16 Feb 2025 15:57:38 -0600 [thread overview]
Message-ID: <20250216215738.GF1233568@bill-the-cat> (raw)
In-Reply-To: <20250216204421.3560012-1-sjg@chromium.org>
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On Sun, Feb 16, 2025 at 01:43:45PM -0700, Simon Glass wrote:
> U-Boot can start and boot an OS in both qemu-x86 and qemu-x86_64 but it
> is not perfect.
>
> With both builds, executing the VESA ROM causes an intermittent hang, at
> least on some AMD CPUs.
>
> With qemu-x86_64 kvm cannot be used since the move to long mode (64-bit)
> is done in a way that works on real hardware but not with QEMU. This
> means that performance is 4-5x slower than it could be, at least on my
> CPU.
>
> We can work around the first problem by using Bochs, which is anyway a
> better choice than VESA for QEMU. The second can be addressed by using
> the same descriptor across the jump to long mode.
>
> With an MTRR fix this allows booting into Ubuntu on qemu-x86_64
This seems needlessly not against mainline.
--
Tom
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next prev parent reply other threads:[~2025-02-16 21:58 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-16 20:43 [PATCH v2 00/28] x86: Improve operation under QEMU Simon Glass
2025-02-16 20:43 ` [PATCH v2 02/28] x86: qemu: Switch to bochs display Simon Glass
2025-02-16 20:43 ` [PATCH v2 03/28] x86: qemu: Enable dhrystone Simon Glass
2025-02-16 20:43 ` [PATCH v2 04/28] x86: qemu: Avoid accessing BSS too early Simon Glass
2025-02-16 21:13 ` [PATCH v2 00/28] x86: Improve operation under QEMU Paolo Bonzini
2025-02-17 13:16 ` Simon Glass
2025-02-16 21:57 ` Tom Rini [this message]
2025-02-17 13:14 ` Simon Glass
2025-02-17 14:05 ` Tom Rini
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