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Re: [PATCH][4.15] x86/shadow: replace bogus return path in shadow_get_page_from_l1e()
- To: Jan Beulich <jbeulich@xxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>
- From: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
- Date: Fri, 26 Feb 2021 15:21:43 +0000
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- Cc: Tim Deegan <tim@xxxxxxx>, George Dunlap <george.dunlap@xxxxxxxxxx>, "Wei Liu" <wl@xxxxxxx>, Roger Pau Monné <roger.pau@xxxxxxxxxx>, Ian Jackson <iwj@xxxxxxxxxxxxxx>
- Delivery-date: Fri, 26 Feb 2021 15:22:12 +0000
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On 26/02/2021 15:08, Jan Beulich wrote:
> Prior to be640b1800bb ("x86: make get_page_from_l1e() return a proper
> error code") a positive return value did indicate an error. Said commit
> failed to adjust this return path, but luckily the only caller has
> always been inside a shadow_mode_refcounts() conditional.
>
> Subsequent changes caused 1 to end up at the default (error) label in
> the caller's switch() again, but the returning of 1 (== _PAGE_PRESENT)
> is still rather confusing here, and a latent risk.
>
> Convert to an ASSERT() instead, just in case any new caller would
> appear.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Yikes, and only 9 years to notice.
Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
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