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Date: Wed, 24 Apr 2024 10:01:10 -0700
From: Elliot Berman <quic_eberman@quicinc.com>
To: Srivatsa Vaddagiri <quic_svaddagi@quicinc.com>
CC: Alex Elder <elder@linaro.org>,
        Srinivas Kandagatla
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Subject: Re: [PATCH v17 15/35] virt: gunyah: Add proxy-scheduled vCPUs
Message-ID: <20240424095405136-0700.eberman@hu-eberman-lv.qualcomm.com>
References: <20240222-gunyah-v17-0-1e9da6763d38@quicinc.com>
 <20240222-gunyah-v17-15-1e9da6763d38@quicinc.com>
 <20240424093957.GY440762@quicinc.com>
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In-Reply-To: <20240424093957.GY440762@quicinc.com>

On Wed, Apr 24, 2024 at 03:09:57PM +0530, Srivatsa Vaddagiri wrote:
> * Elliot Berman <quic_eberman@quicinc.com> [2024-02-22 15:16:38]:
> 
> > +/**
> > + * struct gunyah_vm_exit_info - Reason for VM exit as reported by Gunyah
> > + * See Gunyah documentation for values.
> > + * @type: Describes how VM exited
> > + * @padding: padding bytes
> > + * @reason_size: Number of bytes valid for `reason`
> > + * @reason: See Gunyah documentation for interpretation. Note: these values are
> > + *          not interpreted by Linux and need to be converted from little-endian
> > + *          as applicable.
> > + */
> > +struct gunyah_vm_exit_info {
> > +	__u16 type;
> 
> Pls add an enum to describe the various exit types.
> 

When I was first added the exit_info, I thought a bunch on whether to
add the enum. I was thinking that if we add it to the UAPI, kernel need
to parse and validate the values from RM. In the current scheme, I can
leave it to userspace to interpret the value from RM. I could be
convinced to go the other way though. Currently this is less code :) Let
me know your thoughts! 

> > +	__u16 padding;
> > +	__u32 reason_size;
> > +	__u8 reason[GUNYAH_VM_MAX_EXIT_REASON_SIZE];

If we start interpreting the @type, then maybe we should also start
interpreting the @reason, and that will also add debt to the kernel
driver.

Thanks,
Elliot