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From: Daniel Axtens <dja@axtens•net>
To: Nicholas Piggin <npiggin@gmail•com>, kvm-ppc@vger•kernel.org
Cc: linuxppc-dev@lists•ozlabs.org, Nicholas Piggin <npiggin@gmail•com>
Subject: Re: [RFC PATCH 2/9] KVM: PPC: Book3S 64: Move GUEST_MODE_SKIP test into KVM
Date: Fri, 19 Feb 2021 17:03:01 +1100	[thread overview]
Message-ID: <87lfbka92i.fsf@linkitivity.dja.id.au> (raw)
In-Reply-To: <20210202030313.3509446-3-npiggin@gmail.com>

Hi Nick,

> +maybe_skip:
> +	cmpwi	r12,0x200
> +	beq	1f
> +	cmpwi	r12,0x300
> +	beq	1f
> +	cmpwi	r12,0x380
> +	beq	1f
> +#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
> +	/* XXX: cbe stuff? instruction breakpoint? */
> +	cmpwi	r12,0xe02
> +	beq	2f
> +#endif
> +	b	no_skip
> +1:	mfspr	r9,SPRN_SRR0
> +	addi	r9,r9,4
> +	mtspr	SPRN_SRR0,r9
> +	ld	r12,HSTATE_SCRATCH0(r13)
> +	ld	r9,HSTATE_SCRATCH2(r13)
> +	GET_SCRATCH0(r13)
> +	RFI_TO_KERNEL
> +#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
> +2:	mfspr	r9,SPRN_HSRR0
> +	addi	r9,r9,4
> +	mtspr	SPRN_HSRR0,r9
> +	ld	r12,HSTATE_SCRATCH0(r13)
> +	ld	r9,HSTATE_SCRATCH2(r13)
> +	GET_SCRATCH0(r13)
> +	HRFI_TO_KERNEL
> +#endif

If I understand correctly, label 1 is the kvmppc_skip_interrupt and
label 2 is the kvmppc_skip_Hinterrupt. Would it be easier to understand
if we used symbolic labels, or do you think the RFI_TO_KERNEL vs
HRFI_TO_KERNEL and other changes are sufficient?

Apart from that, I haven't checked the precise copy-paste to make sure
nothing has changed by accident, but I am able to follow the general
idea of the patch and am vigorously in favour of anything that
simplifies our exception/interrupt paths!

Kind regards,
Daniel

> -- 
> 2.23.0

  parent reply	other threads:[~2021-02-19  6:03 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-02  3:03 [RFC PATCH 0/9] KVM: PPC: Book3S: C-ify the P9 entry/exit code Nicholas Piggin
2021-02-02  3:03 ` [RFC PATCH 1/9] KVM: PPC: Book3S 64: move KVM interrupt entry to a common entry point Nicholas Piggin
2021-02-05 21:28   ` Fabiano Rosas
2021-02-19  5:18   ` Daniel Axtens
2021-02-19  8:03     ` Nicholas Piggin
2021-02-02  3:03 ` [RFC PATCH 2/9] KVM: PPC: Book3S 64: Move GUEST_MODE_SKIP test into KVM Nicholas Piggin
2021-02-12 20:33   ` Fabiano Rosas
2021-02-19  7:53     ` Nicholas Piggin
2021-02-19  6:03   ` Daniel Axtens [this message]
2021-02-19  7:56     ` Nicholas Piggin
2021-02-02  3:03 ` [RFC PATCH 3/9] KVM: PPC: Book3S 64: add hcall interrupt handler Nicholas Piggin
2021-02-12 20:33   ` Fabiano Rosas
2021-02-02  3:03 ` [RFC PATCH 4/9] KVM: PPC: Book3S HV: Move hcall early register setup to KVM Nicholas Piggin
2021-02-02  3:03 ` [RFC PATCH 5/9] powerpc/64s: Remove EXSLB interrupt save area Nicholas Piggin
2021-02-02  3:03 ` [RFC PATCH 6/9] KVM: PPC: Book3S HV: Move interrupt early register setup to KVM Nicholas Piggin
2021-02-02  3:03 ` [RFC PATCH 7/9] KVM: PPC: Book3S HV: move bad_host_intr check to HV handler Nicholas Piggin
2021-02-02  3:03 ` [RFC PATCH 8/9] KVM: PPC: Book3S HV: Minimise hcall handler calling convention differences Nicholas Piggin
2021-02-02  3:03 ` [RFC PATCH 9/9] KVM: PPC: Book3S HV: Implement the rest of the P9 entry/exit handling in C Nicholas Piggin

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