linux-kernel - Re: [PATCH v3 2/5] x86/sgx: Use sgx_free_epc_page() in sgx_reclaim

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Message-ID: <b223ea92-8b20-def3-7bd0-2cc44474bd78@intel.com>
Date:   Wed, 3 Mar 2021 08:59:17 -0800
From:   Dave Hansen <dave.hansen@...el.com>
To:     Jarkko Sakkinen <jarkko@...nel.org>, linux-sgx@...r.kernel.org
Cc:     Dave Hansen <dave.hansen@...ux.intel.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/5] x86/sgx: Use sgx_free_epc_page() in
 sgx_reclaim_pages()

On 3/3/21 7:03 AM, Jarkko Sakkinen wrote:
> diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> index 52d070fb4c9a..ed99c60024dc 100644
> --- a/arch/x86/kernel/cpu/sgx/main.c
> +++ b/arch/x86/kernel/cpu/sgx/main.c
> @@ -305,7 +305,6 @@ static void sgx_reclaim_pages(void)
>  {
>  	struct sgx_epc_page *chunk[SGX_NR_TO_SCAN];
>  	struct sgx_backing backing[SGX_NR_TO_SCAN];
> -	struct sgx_epc_section *section;
>  	struct sgx_encl_page *encl_page;
>  	struct sgx_epc_page *epc_page;
>  	pgoff_t page_index;
> @@ -378,11 +377,7 @@ static void sgx_reclaim_pages(void)
>  		kref_put(&encl_page->encl->refcount, sgx_encl_release);
>  		epc_page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
>  
> -		section = &sgx_epc_sections[epc_page->section];
> -		spin_lock(&section->lock);
> -		list_add_tail(&epc_page->list, &section->page_list);
> -		section->free_cnt++;
> -		spin_unlock(&section->lock);
> +		sgx_free_epc_page(epc_page);
>  	}
>  }

In current upstream (3fb6d0e00e), sgx_free_epc_page() calls __eremove().
 This code does not call __eremove().  That seems to be changing
behavior where none was intended.

Was this, perhaps, based on top of Kai's series that changes the
behavior of sgx_free_epc_page()?