Message-ID: <1c91b777-982e-e71a-4829-51744e9555c5@arm.com>
Date:   Fri, 3 Mar 2023 09:54:47 +0000
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Subject: Re: [RFC] Support for Arm CCA VMs on Linux
To:     Jean-Philippe Brucker <jean-philippe@linaro.org>,
        Itaru Kitayama <itaru.kitayama@gmail.com>
Cc:     linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org, kvmarm@lists.linux.dev,
        linux-arm-kernel@lists.infradead.org,
        Alexandru Elisei <alexandru.elisei@arm.com>,
        Andrew Jones <andrew.jones@linux.dev>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Chao Peng <chao.p.peng@linux.intel.com>,
        Christoffer Dall <christoffer.dall@arm.com>,
        Fuad Tabba <tabba@google.com>,
        James Morse <james.morse@arm.com>,
        Joey Gouly <Joey.Gouly@arm.com>, Marc Zyngier <maz@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Oliver Upton <oliver.upton@linux.dev>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Quentin Perret <qperret@google.com>,
        Sean Christopherson <seanjc@google.com>,
        Steven Price <steven.price@arm.com>,
        Thomas Huth <thuth@redhat.com>, Will Deacon <will@kernel.org>,
        Zenghui Yu <yuzenghui@huawei.com>, kvmarm@lists.cs.columbia.edu
References: <20230127112248.136810-1-suzuki.poulose@arm.com>
 <Y9PtKJ3Wicc19JF1@myrica>
 <CANW9uyud8RTkqgiL=64wV712QMxtAyubqeyCJ0vpcADJ42VqJA@mail.gmail.com>
 <Y/8Y3WLmiw6+Z5AS@myrica>
 <CANW9uysnvGCwANu+_6dp9+3rvHGOkThT9d0K2qpQV4exdmYWoA@mail.gmail.com>
 <20230303094618.GC361458@myrica>
From:   Suzuki K Poulose <suzuki.poulose@arm.com>
In-Reply-To: <20230303094618.GC361458@myrica>
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On 03/03/2023 09:46, Jean-Philippe Brucker wrote:
> On Thu, Mar 02, 2023 at 07:12:24AM +0900, Itaru Kitayama wrote:
>>>> I've tried your series in Real on CCA Host, but the KVM arch init
>>>> emits an Invalid argument error and terminates.
> 
> This was the KVM_SET_ONE_REG for the SVE vector size. During my tests I
> didn't enable SVE in the host but shrinkwrap enables more options.

Does the Qemu check for SVE capability on /dev/kvm ? For kvmtool, we
changed to using the VM instance and that would prevent using SVE,
until the RMM supports it.

Suzuki

> 
> Until we figure out support for SVE, disable it on the QEMU command-line
> (similarly to '--disable-sve' needed for kvmtool boot):
> 
> 	-cpu host,sve=off
> 
> Thanks,
> Jean