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From: Jan Beulich <jbeulich@suse.com>
To: Luca Fancellu <luca.fancellu@arm.com>
Cc: bertrand.marquis@arm.com, wei.chen@arm.com,
	Stefano Stabellini <sstabellini@kernel.org>,
	Julien Grall <julien@xen.org>,
	Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	George Dunlap <george.dunlap@citrix.com>,
	Ian Jackson <iwj@xenproject.org>, Wei Liu <wl@xen.org>,
	xen-devel@lists.xenproject.org
Subject: Re: [PATCH v2 3/4] xen/arm: Reserve domid 0 for Dom0
Date: Thu, 8 Apr 2021 12:46:29 +0200	[thread overview]
Message-ID: <19fd45ff-b373-dd89-9377-79cb77ffee5b@suse.com> (raw)
In-Reply-To: <20210408094818.8173-4-luca.fancellu@arm.com>

On 08.04.2021 11:48, Luca Fancellu wrote:
> --- a/xen/common/domctl.c
> +++ b/xen/common/domctl.c
> @@ -419,7 +419,7 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl)
>              {
>                  if ( dom == DOMID_FIRST_RESERVED )
>                      dom = 1;
> -                if ( is_free_domid(dom) )
> +                if ( (dom != 0) && is_free_domid(dom) )
>                      break;
>              }
>  

I don't think this change is needed - I don't see how dom could
ever end up being zero. The code is already intended to be safe
wrt accidentally creating a domain with ID zero. (Granted "rover"
would benefit from being moved into the yet more narrow scope,
which would make this even more obvious.)

Jan


  reply	other threads:[~2021-04-08 10:46 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-08  9:48 [PATCH v2 0/4] xen/arm: Prevent Dom0 to be loaded when using dom0less Luca Fancellu
2021-04-08  9:48 ` [PATCH v2 1/4] xen/arm: Move dom0 creation in domain_build.c Luca Fancellu
2021-04-09  8:30   ` Julien Grall
2021-04-09  9:51     ` Luca Fancellu
2021-04-08  9:48 ` [PATCH v2 2/4] xen/arm: Handle cases when hardware_domain is NULL Luca Fancellu
2021-04-08 10:17   ` Jan Beulich
2021-04-08 13:11     ` Luca Fancellu
2021-04-08 14:36       ` Jan Beulich
2021-04-08 14:58         ` Luca Fancellu
2021-04-08  9:48 ` [PATCH v2 3/4] xen/arm: Reserve domid 0 for Dom0 Luca Fancellu
2021-04-08 10:46   ` Jan Beulich [this message]
2021-04-08 13:12     ` Luca Fancellu
2021-04-08  9:48 ` [PATCH v2 4/4] xen/arm: Prevent Dom0 to be loaded when using dom0less Luca Fancellu
2021-04-09  9:12   ` Julien Grall
2021-04-09  9:56     ` Luca Fancellu
2021-04-09 10:04       ` Julien Grall

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