Re: [PATCH v1 00/24] Opt-in always-on nVHE hypervisor
On Tue, Nov 10, 2020 at 1:19 PM Marc Zyngier wrote: > > Why? I thought we were trying to kill nVHE off now that newer CPUs > > provide the saner virtualization extensions? > > We can't kill nVHE at all, because that is the only game in town. > You can't even buy a decent machine with VHE, no matter how much money > you put on the table. As I mentioned it earlier, we did this type of nVHE hypervisor and the proof of concept is here: https://github.com/jkrh/kvms See the README. It runs successfully on multiple pieces of arm64 hardware and provides a tiny QEMU based development environment via the makefiles for the QEMU 'max' CPU. The code is rough, the amount of man hours put to it is not sky high, but it does run. I'll update a new kernel patch to patches/ dir for one of the later kernels hopefully next week, up to now we have only supported kernels between 4.9 5.6 as this is what our development hardware(s) run with. It requires a handful of hooks in the kvm code, but the actual kvm calls are just rerouted back to the kernel symbols. This way the hypervisor itself can be kept very tiny. The s2 page tables are fully owned by the hyp and the guests are unmapped from the host memory when configured with the option (we call it host blinding). Multiple VMs can be run without pinning them into the memory. It also provides a tiny out of tree driver prototype stub to protect the critical sections of the kernel memory beyond the kernel's own reach. There are still holes in the implementation such as the virtio-mapback handling via whitelisting and paging integrity checks, and many things are not quite all the way there yet. One step at a time. -- Janne ___ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
Re: [PATCH v2 2/2] KVM: arm64: Workaround firmware wrongly advertising GICv2-on-v3 compatibility
On 2021-01-19 10:09, Shameerali Kolothum Thodi wrote:
-Original Message-
From: Marc Zyngier [mailto:m...@kernel.org]
Sent: 15 January 2021 14:15
To: Ard Biesheuvel
Cc: Linux ARM ; kvmarm
; Shameerali Kolothum Thodi
; James Morse
; Julien Thierry ;
Suzuki K Poulose ; Android Kernel Team
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 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
Thanks,
M.
--
Jazz is not dead. It just smells funny...
___
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RE: [PATCH v2 2/2] KVM: arm64: Workaround firmware wrongly advertising GICv2-on-v3 compatibility
> -Original Message-
> From: Marc Zyngier [mailto:m...@kernel.org]
> Sent: 15 January 2021 14:15
> To: Ard Biesheuvel
> Cc: Linux ARM ; kvmarm
> ; Shameerali Kolothum Thodi
> ; James Morse
> ; Julien Thierry ;
> Suzuki K Poulose ; Android Kernel Team
>
> 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 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
Thanks,
Shameer
> Thanks,
>
> M.
> --
> Jazz is not dead. It just smells funny...
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