On 2021-01-19 10:09, Shameerali Kolothum Thodi wrote:
-----Original Message-----
From: Marc Zyngier [mailto:maz@xxxxxxxxxx]
Sent: 15 January 2021 14:15
To: Ard Biesheuvel <ardb@xxxxxxxxxx>
Cc: Linux ARM <linux-arm-kernel@xxxxxxxxxxxxxxxxxxx>; kvmarm
<kvmarm@xxxxxxxxxxxxxxxxxxxxx>; Shameerali Kolothum Thodi
<shameerali.kolothum.thodi@xxxxxxxxxx>; James Morse
<james.morse@xxxxxxx>; Julien Thierry <julien.thierry.kdev@xxxxxxxxx>;
Suzuki K Poulose <suzuki.poulose@xxxxxxx>; Android Kernel Team
<kernel-team@xxxxxxxxxxx>
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@xxxxxxxxxx> 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.
Nope, I didn't think it was useful to send another series for such
a minor change.
Anyways, tested this series on a D06 with faulty firmware and it is
working as expected.
FWIW,
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@xxxxxxxxxx>
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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