linux-kernel - Re: [PATCH v3 02/14] x86/boot: Add missing handling of setup

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Message-ID: <20210810161932.wdwfu3wosjytdj4h@kernel.org>
Date:   Tue, 10 Aug 2021 19:19:32 +0300
From:   Jarkko Sakkinen <jarkko@...nel.org>
To:     Ross Philipson <ross.philipson@...cle.com>
Cc:     linux-kernel@...r.kernel.org, x86@...nel.org,
        iommu@...ts.linux-foundation.org, linux-integrity@...r.kernel.org,
        linux-doc@...r.kernel.org, dpsmith@...rtussolutions.com,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, hpa@...or.com,
        luto@...capital.net, kanth.ghatraju@...cle.com,
        trenchboot-devel@...glegroups.com
Subject: Re: [PATCH v3 02/14] x86/boot: Add missing handling of
 setup_indirect structures

On Mon, Aug 09, 2021 at 12:38:44PM -0400, Ross Philipson wrote:
> One of the two functions in ioremap.c that handles setup_data was
> missing the correct handling of setup_indirect structures.

What is "correct handling", and how was it broken?

What is 'setup_indirect'?

> Functionality missing from original commit:

Remove this sentence.

> commit b3c72fc9a78e (x86/boot: Introduce setup_indirect)

Should be.

Fixes: b3c72fc9a78e ("x86/boot: Introduce setup_indirect")

 
> Signed-off-by: Ross Philipson <ross.philipson@...cle.com>
> ---
>  arch/x86/mm/ioremap.c | 21 +++++++++++++++++++--
>  1 file changed, 19 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
> index ab74e4f..f2b34c5 100644
> --- a/arch/x86/mm/ioremap.c
> +++ b/arch/x86/mm/ioremap.c
> @@ -669,17 +669,34 @@ static bool __init early_memremap_is_setup_data(resource_size_t phys_addr,
>  
>  	paddr = boot_params.hdr.setup_data;
>  	while (paddr) {
> -		unsigned int len;
> +		unsigned int len, size;
>  
>  		if (phys_addr == paddr)
>  			return true;
>  
>  		data = early_memremap_decrypted(paddr, sizeof(*data));
> +		size = sizeof(*data);
>  
>  		paddr_next = data->next;
>  		len = data->len;
>  
> -		early_memunmap(data, sizeof(*data));
> +		if ((phys_addr > paddr) && (phys_addr < (paddr + len))) {
> +			early_memunmap(data, sizeof(*data));
> +			return true;
> +		}
> +
> +		if (data->type == SETUP_INDIRECT) {
> +			size += len;
> +			early_memunmap(data, sizeof(*data));
> +			data = early_memremap_decrypted(paddr, size);
> +
> +			if (((struct setup_indirect *)data->data)->type != SETUP_INDIRECT) {
> +				paddr = ((struct setup_indirect *)data->data)->addr;
> +				len = ((struct setup_indirect *)data->data)->len;
> +			}
> +		}
> +
> +		early_memunmap(data, size);
>  
>  		if ((phys_addr > paddr) && (phys_addr < (paddr + len)))
>  			return true;
> -- 
> 1.8.3.1
> 
> 

/Jarkko