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Date: Fri, 5 Apr 2024 08:40:40 +0530
From: Pavan Kondeti <quic_pkondeti@quicinc.com>
To: Elliot Berman <quic_eberman@quicinc.com>
CC: Alex Elder <elder@linaro.org>,
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Subject: Re: [PATCH v17 11/35] virt: gunyah: Translate gh_rm_hyp_resource
 into gunyah_resource
Message-ID: <ff6a3fb2-5f1a-4baa-b42a-a7767e92885a@quicinc.com>
References: <20240222-gunyah-v17-0-1e9da6763d38@quicinc.com>
 <20240222-gunyah-v17-11-1e9da6763d38@quicinc.com>
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In-Reply-To: <20240222-gunyah-v17-11-1e9da6763d38@quicinc.com>

On Thu, Feb 22, 2024 at 03:16:34PM -0800, Elliot Berman wrote:
> When booting a Gunyah virtual machine, the host VM may gain capabilities
> to interact with resources for the guest virtual machine. Examples of
> such resources are vCPUs or message queues. To use those resources, we
> need to translate the RM response into a gunyah_resource structure which
> are useful to Linux drivers. Presently, Linux drivers need only to know
> the type of resource, the capability ID, and an interrupt.
> 
> On ARM64 systems, the interrupt reported by Gunyah is the GIC interrupt
> ID number and always a SPI or extended SPI.
> 
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
>  arch/arm64/include/asm/gunyah.h | 36 ++++++++++++++++++++++
>  drivers/virt/gunyah/rsc_mgr.c   | 67 +++++++++++++++++++++++++++++++++++++++++
>  drivers/virt/gunyah/rsc_mgr.h   |  5 +++
>  include/linux/gunyah.h          |  2 ++
>  4 files changed, 110 insertions(+)
> 
> diff --git a/arch/arm64/include/asm/gunyah.h b/arch/arm64/include/asm/gunyah.h
> new file mode 100644
> index 0000000000000..0cd3debe22b64
> --- /dev/null
> +++ b/arch/arm64/include/asm/gunyah.h
> @@ -0,0 +1,36 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +#ifndef _ASM_GUNYAH_H
> +#define _ASM_GUNYAH_H
> +
> +#include <linux/irq.h>
> +#include <linux/irqdomain.h>
> +
> +static inline int arch_gunyah_fill_irq_fwspec_params(u32 virq,
> +						 struct irq_fwspec *fwspec)
> +{
> +	/* Assume that Gunyah gave us an SPI or ESPI; defensively check it */
> +	if (WARN(virq < 32, "Unexpected virq: %d\n", virq)) {
> +		return -EINVAL;
> +	} else if (virq <= 1019) {
> +		fwspec->param_count = 3;
> +		fwspec->param[0] = 0; /* GIC_SPI */
> +		fwspec->param[1] = virq - 32; /* virq 32 -> SPI 0 */
> +		fwspec->param[2] = IRQ_TYPE_EDGE_RISING;
> +	} else if (WARN(virq < 4096, "Unexpected virq: %d\n", virq)) {
> +		return -EINVAL;
> +	} else if (virq < 5120) {
> +		fwspec->param_count = 3;
> +		fwspec->param[0] = 2; /* GIC_ESPI */
> +		fwspec->param[1] = virq - 4096; /* virq 4096 -> ESPI 0 */
> +		fwspec->param[2] = IRQ_TYPE_EDGE_RISING;
> +	} else {
> +		WARN(1, "Unexpected virq: %d\n", virq);
> +		return -EINVAL;
> +	}
> +	return 0;
> +}
> +

__get_intid_range() in gic-v3 driver looks more pleasing. Other than
that the logic for the translation looks good to me.

Thanks,
Pavan