linux-kernel - Re: [PATCH v2 1/3] hyperv: Convert hypercall statuses to linux error codes

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <b4887ddf-a296-4f2b-8fb8-a5f9c681142a@linux.microsoft.com>
Date: Thu, 20 Feb 2025 10:49:52 -0800
From: Easwar Hariharan <eahariha@...ux.microsoft.com>
To: Nuno Das Neves <nunodasneves@...ux.microsoft.com>
Cc: linux-hyperv@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
 linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
 iommu@...ts.linux.dev, mhklinux@...look.com, eahariha@...ux.microsoft.com,
 kys@...rosoft.com, haiyangz@...rosoft.com, wei.liu@...nel.org,
 decui@...rosoft.com, catalin.marinas@....com, will@...nel.org,
 tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
 dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com,
 daniel.lezcano@...aro.org, joro@...tes.org, robin.murphy@....com,
 arnd@...db.de, jinankjain@...ux.microsoft.com, muminulrussell@...il.com,
 skinsburskii@...ux.microsoft.com, mukeshrathor@...rosoft.com
Subject: Re: [PATCH v2 1/3] hyperv: Convert hypercall statuses to linux error
 codes

On 2/20/2025 10:33 AM, Nuno Das Neves wrote:
> Return linux-friendly error codes from hypercall helper functions,
> which allows them to be used more flexibly.
> 
> Introduce hv_result_to_errno() for this purpose, which also handles
> the special value U64_MAX returned from hv_do_hypercall().
> 
> Signed-off-by: Nuno Das Neves <nunodasneves@...ux.microsoft.com>
> ---
>  drivers/hv/hv_common.c         | 34 ++++++++++++++++++++++++++++++++++
>  drivers/hv/hv_proc.c           |  6 +++---
>  include/asm-generic/mshyperv.h |  1 +
>  3 files changed, 38 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
> index ee3083937b4f..2120aead98d9 100644
> --- a/drivers/hv/hv_common.c
> +++ b/drivers/hv/hv_common.c
> @@ -683,3 +683,37 @@ u64 __weak hv_tdx_hypercall(u64 control, u64 param1, u64 param2)
>  	return HV_STATUS_INVALID_PARAMETER;
>  }
>  EXPORT_SYMBOL_GPL(hv_tdx_hypercall);
> +
> +/* Convert a hypercall result into a linux-friendly error code. */
> +int hv_result_to_errno(u64 status)
> +{
> +	/* hv_do_hypercall() may return U64_MAX, hypercalls aren't possible */
> +	if (unlikely(status == U64_MAX))
> +		return -EOPNOTSUPP;
> +	/*
> +	 * A failed hypercall is usually only recoverable (or loggable) near
> +	 * the call site where the HV_STATUS_* code is known. So the errno
> +	 * it gets converted to is not too useful further up the stack.
> +	 * Provice a few mappings that could be useful, and revert to -EIO

Typo: Provide

Otherwise, looks good to me.

Reviewed-by: Easwar Hariharan <eahariha@...ux.microsoft.com>

Thanks,
Easwar (he/him)