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Re: [PATCH v7 01/12] xen/arm: enable SVE extension for Xen
- To: Julien Grall <julien@xxxxxxx>
- From: Bertrand Marquis <Bertrand.Marquis@xxxxxxx>
- Date: Wed, 24 May 2023 14:30:16 +0000
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- Cc: Luca Fancellu <Luca.Fancellu@xxxxxxx>, Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxx>, Wei Chen <Wei.Chen@xxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
- Delivery-date: Wed, 24 May 2023 14:30:38 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
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- Thread-topic: [PATCH v7 01/12] xen/arm: enable SVE extension for Xen
Hi Julien,
> On 24 May 2023, at 11:58, Julien Grall <julien@xxxxxxx> wrote:
>
> Hi,
>
> On 24/05/2023 10:01, Bertrand Marquis wrote:
>>> diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c
>>> index c4ec38bb2554..83b84368f6d5 100644
>>> --- a/xen/arch/arm/cpufeature.c
>>> +++ b/xen/arch/arm/cpufeature.c
>>> @@ -9,6 +9,7 @@
>>> #include <xen/init.h>
>>> #include <xen/smp.h>
>>> #include <xen/stop_machine.h>
>>> +#include <asm/arm64/sve.h>
>>> #include <asm/cpufeature.h>
>>>
>>> DECLARE_BITMAP(cpu_hwcaps, ARM_NCAPS);
>>> @@ -143,6 +144,9 @@ void identify_cpu(struct cpuinfo_arm *c)
>>>
>>> c->zfr64.bits[0] = READ_SYSREG(ID_AA64ZFR0_EL1);
>>>
>>> + if ( cpu_has_sve )
>>> + c->zcr64.bits[0] = compute_max_zcr();
>>> +
>>> c->dczid.bits[0] = READ_SYSREG(DCZID_EL0);
>>>
>>> c->ctr.bits[0] = READ_SYSREG(CTR_EL0);
>>> @@ -199,7 +203,7 @@ static int __init create_guest_cpuinfo(void)
>>> guest_cpuinfo.pfr64.mpam = 0;
>>> guest_cpuinfo.pfr64.mpam_frac = 0;
>>>
>>> - /* Hide SVE as Xen does not support it */
>>> + /* Hide SVE by default to the guests */
>> Everything is for guests and as Jan mentioned in an other comment
>> this could be wrongly interpreted.
>
> (Not directly related to this patch, so no changes expected here)
>
> Hmmm... The name of the function/variable is confusing as well given that the
> cpuinfo should also apply to dom0. Should we s/guest/domain/?
Would make sense to do some kind of coherency check here to use domain whenever
something is for dom0 or guest.
So yes that would be a good idea and I can add this to my todolist (after SVE
is merged to prevent conflicts).
Cheers
Bertrand
>
> Cheers,
>
> --
> Julien Grall
|
