* [PATCH] kvmtool: arm64: Report missing support for 32bit guests
@ 2020-07-01 14:20 ` Suzuki K Poulose
0 siblings, 0 replies; 15+ messages in thread
From: Suzuki K Poulose @ 2020-07-01 14:20 UTC (permalink / raw)
To: kvm
Cc: kvmarm, andre.przywara, linux-arm-kernel, Suzuki K Poulose,
Will Deacon, Sami Mujawar
When the host doesn't support 32bit guests, the kvmtool fails
without a proper message on what is wrong. i.e,
$ lkvm run -c 1 Image --aarch32
# lkvm run -k Image -m 256 -c 1 --name guest-105618
Fatal: Unable to initialise vcpu
Given that there is no other easy way to check if the host supports 32bit
guests, it is always good to report this by checking the capability, rather
than leaving the users to hunt this down by looking at the code!
After this patch:
$ lkvm run -c 1 Image --aarch32
# lkvm run -k Image -m 256 -c 1 --name guest-105695
Fatal: 32bit guests are not supported
Cc: Will Deacon <will@kernel.org>
Reported-by: Sami Mujawar <sami.mujawar@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
arm/kvm-cpu.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
index 554414f..2acecae 100644
--- a/arm/kvm-cpu.c
+++ b/arm/kvm-cpu.c
@@ -46,6 +46,10 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id)
.features = ARM_VCPU_FEATURE_FLAGS(kvm, cpu_id)
};
+ if (kvm->cfg.arch.aarch32_guest &&
+ !kvm__supports_extension(kvm, KVM_CAP_ARM_EL1_32BIT))
+ die("32bit guests are not supported\n");
+
vcpu = calloc(1, sizeof(struct kvm_cpu));
if (!vcpu)
return NULL;
--
2.24.1
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH] kvmtool: arm64: Report missing support for 32bit guests
@ 2020-07-01 14:20 ` Suzuki K Poulose
0 siblings, 0 replies; 15+ messages in thread
From: Suzuki K Poulose @ 2020-07-01 14:20 UTC (permalink / raw)
To: kvm
Cc: Suzuki K Poulose, andre.przywara, Sami Mujawar, Will Deacon,
kvmarm, linux-arm-kernel
When the host doesn't support 32bit guests, the kvmtool fails
without a proper message on what is wrong. i.e,
$ lkvm run -c 1 Image --aarch32
# lkvm run -k Image -m 256 -c 1 --name guest-105618
Fatal: Unable to initialise vcpu
Given that there is no other easy way to check if the host supports 32bit
guests, it is always good to report this by checking the capability, rather
than leaving the users to hunt this down by looking at the code!
After this patch:
$ lkvm run -c 1 Image --aarch32
# lkvm run -k Image -m 256 -c 1 --name guest-105695
Fatal: 32bit guests are not supported
Cc: Will Deacon <will@kernel.org>
Reported-by: Sami Mujawar <sami.mujawar@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
arm/kvm-cpu.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
index 554414f..2acecae 100644
--- a/arm/kvm-cpu.c
+++ b/arm/kvm-cpu.c
@@ -46,6 +46,10 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id)
.features = ARM_VCPU_FEATURE_FLAGS(kvm, cpu_id)
};
+ if (kvm->cfg.arch.aarch32_guest &&
+ !kvm__supports_extension(kvm, KVM_CAP_ARM_EL1_32BIT))
+ die("32bit guests are not supported\n");
+
vcpu = calloc(1, sizeof(struct kvm_cpu));
if (!vcpu)
return NULL;
--
2.24.1
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 15+ messages in thread* Re: [PATCH] kvmtool: arm64: Report missing support for 32bit guests
2020-07-01 14:20 ` Suzuki K Poulose
(?)
@ 2020-07-01 15:42 ` Marc Zyngier
-1 siblings, 0 replies; 15+ messages in thread
From: Marc Zyngier @ 2020-07-01 15:42 UTC (permalink / raw)
To: Suzuki K Poulose
Cc: kvm, andre.przywara, Sami Mujawar, Will Deacon, kvmarm,
linux-arm-kernel
On 2020-07-01 15:20, Suzuki K Poulose wrote:
> When the host doesn't support 32bit guests, the kvmtool fails
> without a proper message on what is wrong. i.e,
>
> $ lkvm run -c 1 Image --aarch32
> # lkvm run -k Image -m 256 -c 1 --name guest-105618
> Fatal: Unable to initialise vcpu
>
> Given that there is no other easy way to check if the host supports
> 32bit
> guests, it is always good to report this by checking the capability,
> rather
> than leaving the users to hunt this down by looking at the code!
>
> After this patch:
>
> $ lkvm run -c 1 Image --aarch32
> # lkvm run -k Image -m 256 -c 1 --name guest-105695
> Fatal: 32bit guests are not supported
Fancy!
>
> Cc: Will Deacon <will@kernel.org>
> Reported-by: Sami Mujawar <sami.mujawar@arm.com>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> ---
> arm/kvm-cpu.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
> index 554414f..2acecae 100644
> --- a/arm/kvm-cpu.c
> +++ b/arm/kvm-cpu.c
> @@ -46,6 +46,10 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm,
> unsigned long cpu_id)
> .features = ARM_VCPU_FEATURE_FLAGS(kvm, cpu_id)
> };
>
> + if (kvm->cfg.arch.aarch32_guest &&
> + !kvm__supports_extension(kvm, KVM_CAP_ARM_EL1_32BIT))
Can you please check that this still compiles for 32bit host?
> + die("32bit guests are not supported\n");
> +
> vcpu = calloc(1, sizeof(struct kvm_cpu));
> if (!vcpu)
> return NULL;
With the above detail checked,
Acked-by: Marc Zyngier <maz@kernel.org>
M.
--
Who you jivin' with that Cosmik Debris?
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [PATCH] kvmtool: arm64: Report missing support for 32bit guests
@ 2020-07-01 15:42 ` Marc Zyngier
0 siblings, 0 replies; 15+ messages in thread
From: Marc Zyngier @ 2020-07-01 15:42 UTC (permalink / raw)
To: Suzuki K Poulose
Cc: kvm, andre.przywara, Sami Mujawar, Will Deacon, kvmarm,
linux-arm-kernel
On 2020-07-01 15:20, Suzuki K Poulose wrote:
> When the host doesn't support 32bit guests, the kvmtool fails
> without a proper message on what is wrong. i.e,
>
> $ lkvm run -c 1 Image --aarch32
> # lkvm run -k Image -m 256 -c 1 --name guest-105618
> Fatal: Unable to initialise vcpu
>
> Given that there is no other easy way to check if the host supports
> 32bit
> guests, it is always good to report this by checking the capability,
> rather
> than leaving the users to hunt this down by looking at the code!
>
> After this patch:
>
> $ lkvm run -c 1 Image --aarch32
> # lkvm run -k Image -m 256 -c 1 --name guest-105695
> Fatal: 32bit guests are not supported
Fancy!
>
> Cc: Will Deacon <will@kernel.org>
> Reported-by: Sami Mujawar <sami.mujawar@arm.com>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> ---
> arm/kvm-cpu.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
> index 554414f..2acecae 100644
> --- a/arm/kvm-cpu.c
> +++ b/arm/kvm-cpu.c
> @@ -46,6 +46,10 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm,
> unsigned long cpu_id)
> .features = ARM_VCPU_FEATURE_FLAGS(kvm, cpu_id)
> };
>
> + if (kvm->cfg.arch.aarch32_guest &&
> + !kvm__supports_extension(kvm, KVM_CAP_ARM_EL1_32BIT))
Can you please check that this still compiles for 32bit host?
> + die("32bit guests are not supported\n");
> +
> vcpu = calloc(1, sizeof(struct kvm_cpu));
> if (!vcpu)
> return NULL;
With the above detail checked,
Acked-by: Marc Zyngier <maz@kernel.org>
M.
--
Who you jivin' with that Cosmik Debris?
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [PATCH] kvmtool: arm64: Report missing support for 32bit guests
@ 2020-07-01 15:42 ` Marc Zyngier
0 siblings, 0 replies; 15+ messages in thread
From: Marc Zyngier @ 2020-07-01 15:42 UTC (permalink / raw)
To: Suzuki K Poulose
Cc: kvm, andre.przywara, Sami Mujawar, Will Deacon, kvmarm,
linux-arm-kernel
On 2020-07-01 15:20, Suzuki K Poulose wrote:
> When the host doesn't support 32bit guests, the kvmtool fails
> without a proper message on what is wrong. i.e,
>
> $ lkvm run -c 1 Image --aarch32
> # lkvm run -k Image -m 256 -c 1 --name guest-105618
> Fatal: Unable to initialise vcpu
>
> Given that there is no other easy way to check if the host supports
> 32bit
> guests, it is always good to report this by checking the capability,
> rather
> than leaving the users to hunt this down by looking at the code!
>
> After this patch:
>
> $ lkvm run -c 1 Image --aarch32
> # lkvm run -k Image -m 256 -c 1 --name guest-105695
> Fatal: 32bit guests are not supported
Fancy!
>
> Cc: Will Deacon <will@kernel.org>
> Reported-by: Sami Mujawar <sami.mujawar@arm.com>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> ---
> arm/kvm-cpu.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
> index 554414f..2acecae 100644
> --- a/arm/kvm-cpu.c
> +++ b/arm/kvm-cpu.c
> @@ -46,6 +46,10 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm,
> unsigned long cpu_id)
> .features = ARM_VCPU_FEATURE_FLAGS(kvm, cpu_id)
> };
>
> + if (kvm->cfg.arch.aarch32_guest &&
> + !kvm__supports_extension(kvm, KVM_CAP_ARM_EL1_32BIT))
Can you please check that this still compiles for 32bit host?
> + die("32bit guests are not supported\n");
> +
> vcpu = calloc(1, sizeof(struct kvm_cpu));
> if (!vcpu)
> return NULL;
With the above detail checked,
Acked-by: Marc Zyngier <maz@kernel.org>
M.
--
Who you jivin' with that Cosmik Debris?
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [PATCH] kvmtool: arm64: Report missing support for 32bit guests
2020-07-01 15:42 ` Marc Zyngier
(?)
@ 2020-07-02 15:37 ` Suzuki K Poulose
-1 siblings, 0 replies; 15+ messages in thread
From: Suzuki K Poulose @ 2020-07-02 15:37 UTC (permalink / raw)
To: maz; +Cc: kvm, andre.przywara, sami.mujawar, will, kvmarm, linux-arm-kernel
Hi Marc
On 07/01/2020 04:42 PM, Marc Zyngier wrote:
> On 2020-07-01 15:20, Suzuki K Poulose wrote:
>> When the host doesn't support 32bit guests, the kvmtool fails
>> without a proper message on what is wrong. i.e,
>>
>> $ lkvm run -c 1 Image --aarch32
>> # lkvm run -k Image -m 256 -c 1 --name guest-105618
>> Fatal: Unable to initialise vcpu
>>
>> Given that there is no other easy way to check if the host supports 32bit
>> guests, it is always good to report this by checking the capability,
>> rather
>> than leaving the users to hunt this down by looking at the code!
>>
>> After this patch:
>>
>> $ lkvm run -c 1 Image --aarch32
>> # lkvm run -k Image -m 256 -c 1 --name guest-105695
>> Fatal: 32bit guests are not supported
>
> Fancy!
>
>>
>> Cc: Will Deacon <will@kernel.org>
>> Reported-by: Sami Mujawar <sami.mujawar@arm.com>
>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
>> ---
>> arm/kvm-cpu.c | 4 ++++
>> 1 file changed, 4 insertions(+)
>>
>> diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
>> index 554414f..2acecae 100644
>> --- a/arm/kvm-cpu.c
>> +++ b/arm/kvm-cpu.c
>> @@ -46,6 +46,10 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm,
>> unsigned long cpu_id)
>> .features = ARM_VCPU_FEATURE_FLAGS(kvm, cpu_id)
>> };
>>
>> + if (kvm->cfg.arch.aarch32_guest &&
>> + !kvm__supports_extension(kvm, KVM_CAP_ARM_EL1_32BIT))
>
> Can you please check that this still compiles for 32bit host?
Yes, it does. I have built this on an arm32 rootfs with make ARCH=arm.
The kvm->cfg.arch is common across arm/arm64 and is defined here :
arm/include/arm-common/kvm-config-arch.h
And the aarch32 command line option is only available on aarch64 host.
So this is safe on an arm32 host.
>
>> + die("32bit guests are not supported\n");
>> +
>> vcpu = calloc(1, sizeof(struct kvm_cpu));
>> if (!vcpu)
>> return NULL;
>
> With the above detail checked,
>
> Acked-by: Marc Zyngier <maz@kernel.org>
Thanks
Suzuki
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [PATCH] kvmtool: arm64: Report missing support for 32bit guests
@ 2020-07-02 15:37 ` Suzuki K Poulose
0 siblings, 0 replies; 15+ messages in thread
From: Suzuki K Poulose @ 2020-07-02 15:37 UTC (permalink / raw)
To: maz; +Cc: kvm, andre.przywara, sami.mujawar, will, kvmarm, linux-arm-kernel
Hi Marc
On 07/01/2020 04:42 PM, Marc Zyngier wrote:
> On 2020-07-01 15:20, Suzuki K Poulose wrote:
>> When the host doesn't support 32bit guests, the kvmtool fails
>> without a proper message on what is wrong. i.e,
>>
>> $ lkvm run -c 1 Image --aarch32
>> # lkvm run -k Image -m 256 -c 1 --name guest-105618
>> Fatal: Unable to initialise vcpu
>>
>> Given that there is no other easy way to check if the host supports 32bit
>> guests, it is always good to report this by checking the capability,
>> rather
>> than leaving the users to hunt this down by looking at the code!
>>
>> After this patch:
>>
>> $ lkvm run -c 1 Image --aarch32
>> # lkvm run -k Image -m 256 -c 1 --name guest-105695
>> Fatal: 32bit guests are not supported
>
> Fancy!
>
>>
>> Cc: Will Deacon <will@kernel.org>
>> Reported-by: Sami Mujawar <sami.mujawar@arm.com>
>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
>> ---
>> arm/kvm-cpu.c | 4 ++++
>> 1 file changed, 4 insertions(+)
>>
>> diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
>> index 554414f..2acecae 100644
>> --- a/arm/kvm-cpu.c
>> +++ b/arm/kvm-cpu.c
>> @@ -46,6 +46,10 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm,
>> unsigned long cpu_id)
>> .features = ARM_VCPU_FEATURE_FLAGS(kvm, cpu_id)
>> };
>>
>> + if (kvm->cfg.arch.aarch32_guest &&
>> + !kvm__supports_extension(kvm, KVM_CAP_ARM_EL1_32BIT))
>
> Can you please check that this still compiles for 32bit host?
Yes, it does. I have built this on an arm32 rootfs with make ARCH=arm.
The kvm->cfg.arch is common across arm/arm64 and is defined here :
arm/include/arm-common/kvm-config-arch.h
And the aarch32 command line option is only available on aarch64 host.
So this is safe on an arm32 host.
>
>> + die("32bit guests are not supported\n");
>> +
>> vcpu = calloc(1, sizeof(struct kvm_cpu));
>> if (!vcpu)
>> return NULL;
>
> With the above detail checked,
>
> Acked-by: Marc Zyngier <maz@kernel.org>
Thanks
Suzuki
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [PATCH] kvmtool: arm64: Report missing support for 32bit guests
@ 2020-07-02 15:37 ` Suzuki K Poulose
0 siblings, 0 replies; 15+ messages in thread
From: Suzuki K Poulose @ 2020-07-02 15:37 UTC (permalink / raw)
To: maz; +Cc: kvm, andre.przywara, sami.mujawar, will, kvmarm, linux-arm-kernel
Hi Marc
On 07/01/2020 04:42 PM, Marc Zyngier wrote:
> On 2020-07-01 15:20, Suzuki K Poulose wrote:
>> When the host doesn't support 32bit guests, the kvmtool fails
>> without a proper message on what is wrong. i.e,
>>
>> $ lkvm run -c 1 Image --aarch32
>> # lkvm run -k Image -m 256 -c 1 --name guest-105618
>> Fatal: Unable to initialise vcpu
>>
>> Given that there is no other easy way to check if the host supports 32bit
>> guests, it is always good to report this by checking the capability,
>> rather
>> than leaving the users to hunt this down by looking at the code!
>>
>> After this patch:
>>
>> $ lkvm run -c 1 Image --aarch32
>> # lkvm run -k Image -m 256 -c 1 --name guest-105695
>> Fatal: 32bit guests are not supported
>
> Fancy!
>
>>
>> Cc: Will Deacon <will@kernel.org>
>> Reported-by: Sami Mujawar <sami.mujawar@arm.com>
>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
>> ---
>> arm/kvm-cpu.c | 4 ++++
>> 1 file changed, 4 insertions(+)
>>
>> diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
>> index 554414f..2acecae 100644
>> --- a/arm/kvm-cpu.c
>> +++ b/arm/kvm-cpu.c
>> @@ -46,6 +46,10 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm,
>> unsigned long cpu_id)
>> .features = ARM_VCPU_FEATURE_FLAGS(kvm, cpu_id)
>> };
>>
>> + if (kvm->cfg.arch.aarch32_guest &&
>> + !kvm__supports_extension(kvm, KVM_CAP_ARM_EL1_32BIT))
>
> Can you please check that this still compiles for 32bit host?
Yes, it does. I have built this on an arm32 rootfs with make ARCH=arm.
The kvm->cfg.arch is common across arm/arm64 and is defined here :
arm/include/arm-common/kvm-config-arch.h
And the aarch32 command line option is only available on aarch64 host.
So this is safe on an arm32 host.
>
>> + die("32bit guests are not supported\n");
>> +
>> vcpu = calloc(1, sizeof(struct kvm_cpu));
>> if (!vcpu)
>> return NULL;
>
> With the above detail checked,
>
> Acked-by: Marc Zyngier <maz@kernel.org>
Thanks
Suzuki
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [PATCH] kvmtool: arm64: Report missing support for 32bit guests
2020-07-02 15:37 ` Suzuki K Poulose
(?)
@ 2020-07-02 15:51 ` Marc Zyngier
-1 siblings, 0 replies; 15+ messages in thread
From: Marc Zyngier @ 2020-07-02 15:51 UTC (permalink / raw)
To: Suzuki K Poulose
Cc: kvm, andre.przywara, sami.mujawar, will, kvmarm, linux-arm-kernel
On 2020-07-02 16:37, Suzuki K Poulose wrote:
> Hi Marc
>
> On 07/01/2020 04:42 PM, Marc Zyngier wrote:
>> On 2020-07-01 15:20, Suzuki K Poulose wrote:
>>> When the host doesn't support 32bit guests, the kvmtool fails
>>> without a proper message on what is wrong. i.e,
>>>
>>> $ lkvm run -c 1 Image --aarch32
>>> # lkvm run -k Image -m 256 -c 1 --name guest-105618
>>> Fatal: Unable to initialise vcpu
>>>
>>> Given that there is no other easy way to check if the host supports
>>> 32bit
>>> guests, it is always good to report this by checking the capability,
>>> rather
>>> than leaving the users to hunt this down by looking at the code!
>>>
>>> After this patch:
>>>
>>> $ lkvm run -c 1 Image --aarch32
>>> # lkvm run -k Image -m 256 -c 1 --name guest-105695
>>> Fatal: 32bit guests are not supported
>>
>> Fancy!
>>
>>>
>>> Cc: Will Deacon <will@kernel.org>
>>> Reported-by: Sami Mujawar <sami.mujawar@arm.com>
>>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
>>> ---
>>> arm/kvm-cpu.c | 4 ++++
>>> 1 file changed, 4 insertions(+)
>>>
>>> diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
>>> index 554414f..2acecae 100644
>>> --- a/arm/kvm-cpu.c
>>> +++ b/arm/kvm-cpu.c
>>> @@ -46,6 +46,10 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm
>>> *kvm,
>>> unsigned long cpu_id)
>>> .features = ARM_VCPU_FEATURE_FLAGS(kvm, cpu_id)
>>> };
>>>
>>> + if (kvm->cfg.arch.aarch32_guest &&
>>> + !kvm__supports_extension(kvm, KVM_CAP_ARM_EL1_32BIT))
>>
>> Can you please check that this still compiles for 32bit host?
>
> Yes, it does. I have built this on an arm32 rootfs with make ARCH=arm.
> The kvm->cfg.arch is common across arm/arm64 and is defined here :
>
> arm/include/arm-common/kvm-config-arch.h
I was worried about the availability of KVM_CAP_ARM_EL1_32BIT,
but being a capability, it is common to all arches. It is
KVM_ARM_VCPU_EL1_32BIT that is 32bit only, but that's not what
you are using. Too many flags! ;-)
Thanks,
M.
--
Jazz is not dead. It just smells funny...
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [PATCH] kvmtool: arm64: Report missing support for 32bit guests
@ 2020-07-02 15:51 ` Marc Zyngier
0 siblings, 0 replies; 15+ messages in thread
From: Marc Zyngier @ 2020-07-02 15:51 UTC (permalink / raw)
To: Suzuki K Poulose
Cc: kvm, andre.przywara, sami.mujawar, will, kvmarm, linux-arm-kernel
On 2020-07-02 16:37, Suzuki K Poulose wrote:
> Hi Marc
>
> On 07/01/2020 04:42 PM, Marc Zyngier wrote:
>> On 2020-07-01 15:20, Suzuki K Poulose wrote:
>>> When the host doesn't support 32bit guests, the kvmtool fails
>>> without a proper message on what is wrong. i.e,
>>>
>>> $ lkvm run -c 1 Image --aarch32
>>> # lkvm run -k Image -m 256 -c 1 --name guest-105618
>>> Fatal: Unable to initialise vcpu
>>>
>>> Given that there is no other easy way to check if the host supports
>>> 32bit
>>> guests, it is always good to report this by checking the capability,
>>> rather
>>> than leaving the users to hunt this down by looking at the code!
>>>
>>> After this patch:
>>>
>>> $ lkvm run -c 1 Image --aarch32
>>> # lkvm run -k Image -m 256 -c 1 --name guest-105695
>>> Fatal: 32bit guests are not supported
>>
>> Fancy!
>>
>>>
>>> Cc: Will Deacon <will@kernel.org>
>>> Reported-by: Sami Mujawar <sami.mujawar@arm.com>
>>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
>>> ---
>>> arm/kvm-cpu.c | 4 ++++
>>> 1 file changed, 4 insertions(+)
>>>
>>> diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
>>> index 554414f..2acecae 100644
>>> --- a/arm/kvm-cpu.c
>>> +++ b/arm/kvm-cpu.c
>>> @@ -46,6 +46,10 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm
>>> *kvm,
>>> unsigned long cpu_id)
>>> .features = ARM_VCPU_FEATURE_FLAGS(kvm, cpu_id)
>>> };
>>>
>>> + if (kvm->cfg.arch.aarch32_guest &&
>>> + !kvm__supports_extension(kvm, KVM_CAP_ARM_EL1_32BIT))
>>
>> Can you please check that this still compiles for 32bit host?
>
> Yes, it does. I have built this on an arm32 rootfs with make ARCH=arm.
> The kvm->cfg.arch is common across arm/arm64 and is defined here :
>
> arm/include/arm-common/kvm-config-arch.h
I was worried about the availability of KVM_CAP_ARM_EL1_32BIT,
but being a capability, it is common to all arches. It is
KVM_ARM_VCPU_EL1_32BIT that is 32bit only, but that's not what
you are using. Too many flags! ;-)
Thanks,
M.
--
Jazz is not dead. It just smells funny...
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [PATCH] kvmtool: arm64: Report missing support for 32bit guests
@ 2020-07-02 15:51 ` Marc Zyngier
0 siblings, 0 replies; 15+ messages in thread
From: Marc Zyngier @ 2020-07-02 15:51 UTC (permalink / raw)
To: Suzuki K Poulose
Cc: kvm, andre.przywara, sami.mujawar, will, kvmarm, linux-arm-kernel
On 2020-07-02 16:37, Suzuki K Poulose wrote:
> Hi Marc
>
> On 07/01/2020 04:42 PM, Marc Zyngier wrote:
>> On 2020-07-01 15:20, Suzuki K Poulose wrote:
>>> When the host doesn't support 32bit guests, the kvmtool fails
>>> without a proper message on what is wrong. i.e,
>>>
>>> $ lkvm run -c 1 Image --aarch32
>>> # lkvm run -k Image -m 256 -c 1 --name guest-105618
>>> Fatal: Unable to initialise vcpu
>>>
>>> Given that there is no other easy way to check if the host supports
>>> 32bit
>>> guests, it is always good to report this by checking the capability,
>>> rather
>>> than leaving the users to hunt this down by looking at the code!
>>>
>>> After this patch:
>>>
>>> $ lkvm run -c 1 Image --aarch32
>>> # lkvm run -k Image -m 256 -c 1 --name guest-105695
>>> Fatal: 32bit guests are not supported
>>
>> Fancy!
>>
>>>
>>> Cc: Will Deacon <will@kernel.org>
>>> Reported-by: Sami Mujawar <sami.mujawar@arm.com>
>>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
>>> ---
>>> arm/kvm-cpu.c | 4 ++++
>>> 1 file changed, 4 insertions(+)
>>>
>>> diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
>>> index 554414f..2acecae 100644
>>> --- a/arm/kvm-cpu.c
>>> +++ b/arm/kvm-cpu.c
>>> @@ -46,6 +46,10 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm
>>> *kvm,
>>> unsigned long cpu_id)
>>> .features = ARM_VCPU_FEATURE_FLAGS(kvm, cpu_id)
>>> };
>>>
>>> + if (kvm->cfg.arch.aarch32_guest &&
>>> + !kvm__supports_extension(kvm, KVM_CAP_ARM_EL1_32BIT))
>>
>> Can you please check that this still compiles for 32bit host?
>
> Yes, it does. I have built this on an arm32 rootfs with make ARCH=arm.
> The kvm->cfg.arch is common across arm/arm64 and is defined here :
>
> arm/include/arm-common/kvm-config-arch.h
I was worried about the availability of KVM_CAP_ARM_EL1_32BIT,
but being a capability, it is common to all arches. It is
KVM_ARM_VCPU_EL1_32BIT that is 32bit only, but that's not what
you are using. Too many flags! ;-)
Thanks,
M.
--
Jazz is not dead. It just smells funny...
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH] kvmtool: arm64: Report missing support for 32bit guests
2020-07-01 14:20 ` Suzuki K Poulose
(?)
@ 2020-07-03 12:07 ` Will Deacon
-1 siblings, 0 replies; 15+ messages in thread
From: Will Deacon @ 2020-07-03 12:07 UTC (permalink / raw)
To: Suzuki K Poulose, kvm
Cc: Will Deacon, catalin.marinas, andre.przywara, Sami Mujawar,
kernel-team, kvmarm, linux-arm-kernel
On Wed, 1 Jul 2020 15:20:02 +0100, Suzuki K Poulose wrote:
> When the host doesn't support 32bit guests, the kvmtool fails
> without a proper message on what is wrong. i.e,
>
> $ lkvm run -c 1 Image --aarch32
> # lkvm run -k Image -m 256 -c 1 --name guest-105618
> Fatal: Unable to initialise vcpu
>
> [...]
Applied to kvmtool (master), thanks!
[1/1] kvmtool: arm64: Report missing support for 32bit guests
https://git.kernel.org/will/kvmtool/c/351d931f496a
Cheers,
--
Will
https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [PATCH] kvmtool: arm64: Report missing support for 32bit guests
@ 2020-07-03 12:07 ` Will Deacon
0 siblings, 0 replies; 15+ messages in thread
From: Will Deacon @ 2020-07-03 12:07 UTC (permalink / raw)
To: Suzuki K Poulose, kvm
Cc: catalin.marinas, kernel-team, Will Deacon, kvmarm, andre.przywara,
linux-arm-kernel, Sami Mujawar
On Wed, 1 Jul 2020 15:20:02 +0100, Suzuki K Poulose wrote:
> When the host doesn't support 32bit guests, the kvmtool fails
> without a proper message on what is wrong. i.e,
>
> $ lkvm run -c 1 Image --aarch32
> # lkvm run -k Image -m 256 -c 1 --name guest-105618
> Fatal: Unable to initialise vcpu
>
> [...]
Applied to kvmtool (master), thanks!
[1/1] kvmtool: arm64: Report missing support for 32bit guests
https://git.kernel.org/will/kvmtool/c/351d931f496a
Cheers,
--
Will
https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [PATCH] kvmtool: arm64: Report missing support for 32bit guests
@ 2020-07-03 12:07 ` Will Deacon
0 siblings, 0 replies; 15+ messages in thread
From: Will Deacon @ 2020-07-03 12:07 UTC (permalink / raw)
To: Suzuki K Poulose, kvm
Cc: Will Deacon, catalin.marinas, andre.przywara, Sami Mujawar,
kernel-team, kvmarm, linux-arm-kernel
On Wed, 1 Jul 2020 15:20:02 +0100, Suzuki K Poulose wrote:
> When the host doesn't support 32bit guests, the kvmtool fails
> without a proper message on what is wrong. i.e,
>
> $ lkvm run -c 1 Image --aarch32
> # lkvm run -k Image -m 256 -c 1 --name guest-105618
> Fatal: Unable to initialise vcpu
>
> [...]
Applied to kvmtool (master), thanks!
[1/1] kvmtool: arm64: Report missing support for 32bit guests
https://git.kernel.org/will/kvmtool/c/351d931f496a
Cheers,
--
Will
https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 15+ messages in thread