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From:   Oliver Upton <oliver.upton@linux.dev>
To:     Kristina Martsenko <kristina.martsenko@arm.com>
Cc:     kvm@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
        James Morse <james.morse@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Zenghui Yu <yuzenghui@huawei.com>,
        Will Deacon <will@kernel.org>,
        Cornelia Huck <cohuck@redhat.com>,
        Jing Zhang <jingzhangos@google.com>, kvmarm@lists.linux.dev
Subject: Re: [PATCH v10 06/12] KVM: arm64: Allow userspace to change
 ID_AA64ISAR{0-2}_EL1
Message-ID: <ZRxudJGhSe8dOiDj@linux.dev>
References: <20230920183310.1163034-1-oliver.upton@linux.dev>
 <20230920183310.1163034-7-oliver.upton@linux.dev>
 <80140d61-82e7-2795-409d-2cf6dc4993bc@arm.com>
 <ZQ3UaYTsZ1lVeShQ@linux.dev>
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On Fri, Sep 22, 2023 at 05:52:41PM +0000, Oliver Upton wrote:
> > Nit: it shouldn't be necessary to override BC anymore, as it was recently fixed
> > in the arm64 code:
> >   https://lore.kernel.org/linux-arm-kernel/20230912133429.2606875-1-kristina.martsenko@arm.com/
> 
> Perfect, looks like that patch should go in 6.6 too. Thanks for the fix!

Going to squash the following into the patch:

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index c74920063287..179f82bd90af 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1225,10 +1225,6 @@ static s64 kvm_arm64_ftr_safe_value(u32 id, const struct arm64_ftr_bits *ftrp,
 			break;
 		}
 		break;
-	case SYS_ID_AA64ISAR2_EL1:
-		if (kvm_ftr.shift == ID_AA64ISAR2_EL1_BC_SHIFT)
-			kvm_ftr.type = FTR_LOWER_SAFE;
-		break;
 	case SYS_ID_DFR0_EL1:
 		if (kvm_ftr.shift == ID_DFR0_EL1_PerfMon_SHIFT)
 			kvm_ftr.type = FTR_LOWER_SAFE;

-- 
Thanks,
Oliver