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From: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
To: Marc Zyngier <maz@kernel.org>, Ard Biesheuvel <ardb@kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>,
	James Morse <james.morse@arm.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Android Kernel Team <kernel-team@android.com>,
	kvmarm <kvmarm@lists.cs.columbia.edu>,
	Julien Thierry <julien.thierry.kdev@gmail.com>
Subject: RE: [PATCH v2 2/2] KVM: arm64: Workaround firmware wrongly advertising GICv2-on-v3 compatibility
Date: Tue, 19 Jan 2021 10:09:07 +0000	[thread overview]
Message-ID: <0edcab071c4845f29ec20af630777dce@huawei.com> (raw)
In-Reply-To: <67c2f61a5dd33731cf52b6e26095ed51@kernel.org>



> -----Original Message-----
> From: Marc Zyngier [mailto:maz@kernel.org]
> Sent: 15 January 2021 14:15
> To: Ard Biesheuvel <ardb@kernel.org>
> Cc: Linux ARM <linux-arm-kernel@lists.infradead.org>; kvmarm
> <kvmarm@lists.cs.columbia.edu>; Shameerali Kolothum Thodi
> <shameerali.kolothum.thodi@huawei.com>; James Morse
> <james.morse@arm.com>; Julien Thierry <julien.thierry.kdev@gmail.com>;
> Suzuki K Poulose <suzuki.poulose@arm.com>; Android Kernel Team
> <kernel-team@android.com>
> Subject: Re: [PATCH v2 2/2] KVM: arm64: Workaround firmware wrongly
> advertising GICv2-on-v3 compatibility
> 
> On 2021-01-15 14:08, Ard Biesheuvel wrote:
> > On Fri, 15 Jan 2021 at 15:03, Marc Zyngier <maz@kernel.org> wrote:
> 
> [...]
> 
> >> diff --git a/arch/arm64/kvm/vgic/vgic-v3.c
> >> b/arch/arm64/kvm/vgic/vgic-v3.c index 8e7bf3151057..67b27b47312b
> >> 100644
> >> --- a/arch/arm64/kvm/vgic/vgic-v3.c
> >> +++ b/arch/arm64/kvm/vgic/vgic-v3.c
> >> @@ -584,8 +584,10 @@ early_param("kvm-arm.vgic_v4_enable",
> >> early_gicv4_enable);
> >>  int vgic_v3_probe(const struct gic_kvm_info *info)  {
> >>         u64 ich_vtr_el2 = kvm_call_hyp_ret(__vgic_v3_get_gic_config);
> >> +       bool has_v2;
> >>         int ret;
> >>
> >> +       has_v2 = ich_vtr_el2 >> 63;
> >>         ich_vtr_el2 = (u32)ich_vtr_el2;
> >>
> >>         /*
> >> @@ -605,13 +607,15 @@ int vgic_v3_probe(const struct gic_kvm_info
> >> *info)
> >>                          gicv4_enable ? "en" : "dis");
> >>         }
> >>
> >> +       kvm_vgic_global_state.vcpu_base = 0;
> >> +
> >>         if (!info->vcpu.start) {
> >>                 kvm_info("GICv3: no GICV resource entry\n");
> >> -               kvm_vgic_global_state.vcpu_base = 0;
> >> +       } else if (!has_v2) {
> >> +               pr_warn("CPU interface incapable of MMIO access\n");
> >
> > Could we include FW_BUG here to stress that this is a firmware problem?
> 
> Absolutely! That's what it now looks like:
> 
> [    2.648452] kvm [1]: IPA Size Limit: 40 bits
> [    2.649259] [Firmware Bug]: CPU interface incapable of MMIO access
> [    2.649620] kvm [1]: disabling GICv2 emulation
> [    2.650227] kvm [1]: GIC system register CPU interface enabled
> [    2.652004] kvm [1]: vgic interrupt IRQ9
> [    2.655623] kvm [1]: VHE mode initialized successfully
> 
> Updated version pushed out.

Is there a v3 for this series? I couldn't find one.

Anyways, tested this series on a D06 with faulty firmware and it is working as expected.
FWIW,

   Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>

Thanks,
Shameer

> Thanks,
> 
>          M.
> --
> Jazz is not dead. It just smells funny...

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  reply	other threads:[~2021-01-19 10:10 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-15 14:03 [PATCH v2 0/2] KVM: arm64: Work around firmware wongly advertising GICv2 compatibility Marc Zyngier
2021-01-15 14:03 ` [PATCH v2 1/2] KVM: arm64: Rename __vgic_v3_get_ich_vtr_el2() to __vgic_v3_get_gic_config() Marc Zyngier
2021-01-15 14:03 ` [PATCH v2 2/2] KVM: arm64: Workaround firmware wrongly advertising GICv2-on-v3 compatibility Marc Zyngier
2021-01-15 14:08   ` Ard Biesheuvel
2021-01-15 14:15     ` Marc Zyngier
2021-01-19 10:09       ` Shameerali Kolothum Thodi [this message]
2021-01-19 10:14         ` Marc Zyngier

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