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Re: [PATCH v6 01/12] xen/arm: enable SVE extension for Xen
- To: Julien Grall <julien@xxxxxxx>
- From: Luca Fancellu <Luca.Fancellu@xxxxxxx>
- Date: Fri, 19 May 2023 15:13:51 +0000
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- Cc: Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxx>, Bertrand Marquis <Bertrand.Marquis@xxxxxxx>, Wei Chen <Wei.Chen@xxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
- Delivery-date: Fri, 19 May 2023 15:14:27 +0000
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- Thread-topic: [PATCH v6 01/12] xen/arm: enable SVE extension for Xen
> On 19 May 2023, at 16:00, Julien Grall <julien@xxxxxxx> wrote:
>
>
>
> On 19/05/2023 15:51, Luca Fancellu wrote:
>> /* Control Registers */
>> /*
>> * CPTR_EL2 needs to be written before calling vfp_restore_state, a
>> * synchronization instruction is expected after the write (isb)
>> */
>> WRITE_SYSREG(n->arch.cptr_el2, CPTR_EL2);
>> WRITE_SYSREG(n->arch.cpacr, CPACR_EL1);
>> /*
>> * This write to sysreg CONTEXTIDR_EL1 ensures we don't hit erratum
>> * #852523 (Cortex-A57) or #853709 (Cortex-A72).
>> * I.e DACR32_EL2 is not correctly synchronized.
>> */
>> WRITE_SYSREG(n->arch.contextidr, CONTEXTIDR_EL1);
>> WRITE_SYSREG(n->arch.tpidr_el0, TPIDR_EL0);
>> WRITE_SYSREG(n->arch.tpidrro_el0, TPIDRRO_EL0);
>> WRITE_SYSREG(n->arch.tpidr_el1, TPIDR_EL1);
>> if ( is_32bit_domain(n->domain) && cpu_has_thumbee )
>> {
>> WRITE_SYSREG(n->arch.teecr, TEECR32_EL1);
>> WRITE_SYSREG(n->arch.teehbr, TEEHBR32_EL1);
>> }
>> #ifdef CONFIG_ARM_32
>> WRITE_CP32(n->arch.joscr, JOSCR);
>> WRITE_CP32(n->arch.jmcr, JMCR);
>> #endif
>> isb();
>> /* VFP - call vfp_restore_state after writing on CPTR_EL2 + isb */
>> vfp_restore_state(n);
>> Maybe I misunderstood your preference, do you want me to put the write to
>> CPTR_EL2
>> right before the isb() that precedes vfp_restore_state?
>
> Yes please. Unless there is a reason to keep it "far away". The comments look
> good to me.
Ok, a question regarding README.LinuxPrimitives, is it some file taken from an
automated tool?
Because I see there is some kind of structure, how can I know if my syntax is
correct?
>
> Cheers,
>
> --
> Julien Grall
|
