On 09/07/15 10:48, Mark Rutland wrote:
> On Wed, Jul 08, 2015 at 05:19:06PM +0100, Marc Zyngier wrote:
>> Add a new ARM64_HAS_VIRT_HOST_EXTN features to indicate that the
>> CPU has the ARMv8,1 VHE capability.
>
> Nit: s/,/./
>
> It's probably worth mentioning somewhere that we have to check CurrentEL
> rather than a feature register in case some prior software dropped us to
> EL1N (e.g. if we're a guest under this scheme).
Good point, this is a leftover from a previous version that actually
checked the feature register. I'll clean up the commit log.
Thanks,
M.
> Mark.
>
>>
>> This will be used to trigger kernel patching in KVM.
>>
>> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
>> ---
>> arch/arm64/include/asm/cpufeature.h | 3 ++-
>> arch/arm64/kernel/cpufeature.c | 11 +++++++++++
>> 2 files changed, 13 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
>> index c104421..6c3742d 100644
>> --- a/arch/arm64/include/asm/cpufeature.h
>> +++ b/arch/arm64/include/asm/cpufeature.h
>> @@ -25,8 +25,9 @@
>> #define ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE 1
>> #define ARM64_WORKAROUND_845719 2
>> #define ARM64_HAS_SYSREG_GIC_CPUIF 3
>> +#define ARM64_HAS_VIRT_HOST_EXTN 4
>>
>> -#define ARM64_NCAPS 4
>> +#define ARM64_NCAPS 5
>>
>> #ifndef __ASSEMBLY__
>>
>> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
>> index 5ad86ce..e1dcd63 100644
>> --- a/arch/arm64/kernel/cpufeature.c
>> +++ b/arch/arm64/kernel/cpufeature.c
>> @@ -21,6 +21,7 @@
>> #include <linux/types.h>
>> #include <asm/cpu.h>
>> #include <asm/cpufeature.h>
>> +#include <asm/virt.h>
>>
>> static bool
>> has_id_aa64pfr0_feature(const struct arm64_cpu_capabilities *entry)
>> @@ -31,6 +32,11 @@ has_id_aa64pfr0_feature(const struct arm64_cpu_capabilities *entry)
>> return (val & entry->register_mask) == entry->register_value;
>> }
>>
>> +static bool runs_at_el2(const struct arm64_cpu_capabilities *entry)
>> +{
>> + return is_kernel_in_hyp_mode();
>> +}
>> +
>> static const struct arm64_cpu_capabilities arm64_features[] = {
>> {
>> .desc = "GIC system register CPU interface",
>> @@ -39,6 +45,11 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
>> .register_mask = (0xf << 24),
>> .register_value = (1 << 24),
>> },
>> + {
>> + .desc = "Virtualization Host Extensions",
>> + .capability = ARM64_HAS_VIRT_HOST_EXTN,
>> + .matches = runs_at_el2,
>> + },
>> {},
>> };
>>
>> --
>> 2.1.4
>>
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>> kvmarm@xxxxxxxxxxxxxxxxxxxxx
>> https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
>>
>
--
Jazz is not dead. It just smells funny...
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