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Date: Mon, 11 Mar 2024 10:19:39 -0700
From: Elliot Berman <quic_eberman@quicinc.com>
To: Srivatsa Vaddagiri <quic_svaddagi@quicinc.com>
CC: Alex Elder <elder@linaro.org>,
        Srinivas Kandagatla
	<srinivas.kandagatla@linaro.org>,
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        Will Deacon <will@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
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        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        "Fuad
 Tabba" <tabba@google.com>,
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 Morton" <akpm@linux-foundation.org>,
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Subject: Re: Re: [PATCH v17 11/35] virt: gunyah: Translate gh_rm_hyp_resource
 into gunyah_resource
Message-ID: <20240311101433139-0700.eberman@hu-eberman-lv.qualcomm.com>
Mail-Followup-To: Srivatsa Vaddagiri <quic_svaddagi@quicinc.com>, 
	Alex Elder <elder@linaro.org>, Srinivas Kandagatla <srinivas.kandagatla@linaro.org>, 
	Murali Nalajal <quic_mnalajal@quicinc.com>, Trilok Soni <quic_tsoni@quicinc.com>, 
	Carl van Schaik <quic_cvanscha@quicinc.com>, Philip Derrin <quic_pderrin@quicinc.com>, 
	Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>, Jonathan Corbet <corbet@lwn.net>, 
	Rob Herring <robh+dt@kernel.org>, Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, 
	Conor Dooley <conor+dt@kernel.org>, Catalin Marinas <catalin.marinas@arm.com>, 
	Will Deacon <will@kernel.org>, Konrad Dybcio <konrad.dybcio@linaro.org>, 
	Bjorn Andersson <andersson@kernel.org>, Dmitry Baryshkov <dmitry.baryshkov@linaro.org>, 
	Fuad Tabba <tabba@google.com>, Sean Christopherson <seanjc@google.com>, 
	Andrew Morton <akpm@linux-foundation.org>, linux-arm-msm@vger.kernel.org, linux-doc@vger.kernel.org, 
	linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, 
	linux-mm@kvack.org
References: <20240222-gunyah-v17-0-1e9da6763d38@quicinc.com>
 <20240222-gunyah-v17-11-1e9da6763d38@quicinc.com>
 <20240311053905.GN440762@quicinc.com>
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In-Reply-To: <20240311053905.GN440762@quicinc.com>

On Mon, Mar 11, 2024 at 11:09:05AM +0530, Srivatsa Vaddagiri wrote:
> * Elliot Berman <quic_eberman@quicinc.com> [2024-02-22 15:16:34]:
> 
> > 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>
> 
> Minor nit below. LGTM otherwise
> 
> Reviewed-by: Srivatsa Vaddagiri <quic_svaddagi@quicinc.com>
> 
> > +struct gunyah_resource *
> > +gunyah_rm_alloc_resource(struct gunyah_rm *rm,
> > +			 struct gunyah_rm_hyp_resource *hyp_resource)
> > +{
> > +	struct gunyah_resource *ghrsc;
> > +	int ret;
> > +
> > +	ghrsc = kzalloc(sizeof(*ghrsc), GFP_KERNEL);
> > +	if (!ghrsc)
> > +		return NULL;
> > +
> > +	ghrsc->type = hyp_resource->type;
> > +	ghrsc->capid = le64_to_cpu(hyp_resource->cap_id);
> > +	ghrsc->irq = IRQ_NOTCONNECTED;
> > +	ghrsc->rm_label = le32_to_cpu(hyp_resource->resource_label);
> > +	if (hyp_resource->virq) {
> > +		struct irq_fwspec fwspec;
> > +
> > +
> > +		fwspec.fwnode = rm->parent_fwnode;
> > +		ret = arch_gunyah_fill_irq_fwspec_params(le32_to_cpu(hyp_resource->virq), &fwspec);
> > +		if (ret) {
> > +			dev_err(rm->dev,
> > +				"Failed to translate interrupt for resource %d label: %d: %d\n",
> > +				ghrsc->type, ghrsc->rm_label, ret);
> 
> Not bailing on error here appears wrong. Can you check?
> 

Ah, yes. I'll return ghrsc here. I think it's better than returning
NULL because user of resource might be able to cope without the
interrupt and can let us get a more helpful kernel log messages because
the higher level VM function will complain.

> > +		}
> > +
> > +		ret = irq_create_fwspec_mapping(&fwspec);
> > +		if (ret < 0) {
> > +			dev_err(rm->dev,
> > +				"Failed to allocate interrupt for resource %d label: %d: %d\n",
> > +				ghrsc->type, ghrsc->rm_label, ret);
> > +			kfree(ghrsc);
> > +			return NULL;
> > +		}
> > +		ghrsc->irq = ret;
> > +	}
> > +
> > +	return ghrsc;
> > +}