linux-kernel - Re: [PATCH 3/5] x86/boot/64: Change add_identity

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Date:   Thu, 8 Oct 2020 11:14:12 +0200
From:   Joerg Roedel <jroedel@...e.de>
To:     Arvind Sankar <nivedita@...m.mit.edu>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/5] x86/boot/64: Change add_identity_map() to take size
 for ease of use

On Wed, Oct 07, 2020 at 03:53:49PM -0400, Arvind Sankar wrote:
> Change back the arguments of add_identity_map() to (start, size) instead
> of (start, end). This reverts
> 
>   21cf2372618e ("x86/boot/compressed/64: Change add_identity_map() to take start and end")
> 
> since we will soon have more callers that know the size rather than the
> end address.
> 
> This also makes the #PF handler print the original CR2 value in case of
> error, instead of after aligning to PMD_SIZE.
> 
> Signed-off-by: Arvind Sankar <nivedita@...m.mit.edu>
> ---
>  arch/x86/boot/compressed/ident_map_64.c | 11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c
> index 063a60edcf99..070cda70aef3 100644
> --- a/arch/x86/boot/compressed/ident_map_64.c
> +++ b/arch/x86/boot/compressed/ident_map_64.c
> @@ -90,8 +90,9 @@ static struct x86_mapping_info mapping_info;
>  /*
>   * Adds the specified range to the identity mappings.
>   */
> -static void add_identity_map(unsigned long start, unsigned long end)
> +static void add_identity_map(unsigned long start, unsigned long size)
>  {
> +	unsigned long end = start + size;

This has been discussed during the SEV-ES patch-review already and we
settled on making add_identity_map() take start and end as parameter, as
that is what kernel_ident_mapping_init() also takes as parameters.

So please keep it that way :)

Regards,

	Joerg