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From: Richard Henderson <richard.henderson@linaro.org>
To: Marc Zyngier <marc.zyngier@arm.com>
Cc: Christoffer Dall <christoffer.dall@arm.com>,
	Peter Maydell <peter.maydell@linaro.org>,
	QEMU Developers <qemu-devel@nongnu.org>,
	qemu-arm <qemu-arm@nongnu.org>, Dave Martin <Dave.Martin@arm.com>
Subject: Re: [Qemu-devel] [PATCH v2 0/5] target/arm: KVM vs ARMISARegisters
Date: Sun, 4 Nov 2018 09:50:29 +0000	[thread overview]
Message-ID: <1ee4127a-aa3e-4e19-1dde-af83147f8bc4@linaro.org> (raw)
In-Reply-To: <20181103123246.16b5b101@why.wild-wind.fr.eu.org>

On 11/3/18 12:32 PM, Marc Zyngier wrote:
> We actively hide the LORegion feature from the guest since
> cc33c4e20185a391766ed5e78e2acc97e17ba511 (in the 4.17 time frame), so
> you shouldn't be able to obtain these on a recent host.

I don't think that patch is ideal.

In particular, LOR is a mandatory requirement of ARMv8.1.
The OS can rightly presume it is present in context.

Better, I think, is to trap the LOR registers, as you are doing,
and have them act as RAZ/WI.  This indicates, via LORID_EL1, that
there are zero supported LO regions, which is a valid ARMv8.1
configuration.


r~

  reply	other threads:[~2018-11-04  9:50 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-02 14:54 [Qemu-devel] [PATCH v2 0/5] target/arm: KVM vs ARMISARegisters Richard Henderson
2018-11-02 14:54 ` [Qemu-devel] [PATCH v2 1/5] target/arm: Install ARMISARegisters from kvm host Richard Henderson
2018-11-02 14:54 ` [Qemu-devel] [PATCH v2 2/5] target/arm: Fill in ARMISARegisters for kvm64 Richard Henderson
2018-11-02 14:54 ` [Qemu-devel] [PATCH v2 3/5] target/arm: Introduce read_sys_reg32 for kvm32 Richard Henderson
2018-11-02 14:54 ` [Qemu-devel] [PATCH v2 4/5] target/arm: Fill in ARMISARegisters " Richard Henderson
2018-11-02 14:54 ` [Qemu-devel] [PATCH v2 5/5] target/arm: Convert t32ee from feature bit to isar3 test Richard Henderson
2018-11-02 16:36 ` [Qemu-devel] [PATCH v2 0/5] target/arm: KVM vs ARMISARegisters Peter Maydell
2018-11-02 19:35   ` Christoffer Dall
2018-11-03  9:53     ` Richard Henderson
2018-11-03 12:32       ` Marc Zyngier
2018-11-04  9:50         ` Richard Henderson [this message]
2018-11-04 11:25           ` Marc Zyngier
2018-11-05 11:47             ` Mark Rutland

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