From: Jarkko Sakkinen <jarkko@kernel.org>
To: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Andrew Morton <akpm@linux-foundation.org>,
Shuah Khan <shuah@kernel.org>,
haitao.huang@intel.com, Kai Huang <kai.huang@intel.com>,
x86@kernel.org, linux-sgx@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-kselftest@vger.kernel.org,
Jia Zhang <zhang.jia@linux.alibaba.com>
Subject: Re: [PATCH] x86/sgx: Fix free_cnt counting logic in epc section
Date: Wed, 20 Jan 2021 16:36:31 +0200 [thread overview]
Message-ID: <YAg/705sWZFriAdK@kernel.org> (raw)
In-Reply-To: <20210118133347.99158-1-tianjia.zhang@linux.alibaba.com>
On Mon, Jan 18, 2021 at 09:33:47PM +0800, Tianjia Zhang wrote:
> Increase `section->free_cnt` in sgx_sanitize_section() is
> more reasonable, which is called in ksgxd kernel thread,
> instead of assigning it to epc section pages number at
> initialization. Although this is unlikely to fail, these
> pages cannot be allocated after initialization, and which
> need to be reset by ksgxd.
>
> Reported-by: Jia Zhang <zhang.jia@linux.alibaba.com>
> Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
There is nothing broken in the logic. Convince me otherwise.
I.e. what is exactly broken, and how?
/Jarkko
> ---
> arch/x86/kernel/cpu/sgx/main.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> index c519fc5f6948..9e9a3cf7c00b 100644
> --- a/arch/x86/kernel/cpu/sgx/main.c
> +++ b/arch/x86/kernel/cpu/sgx/main.c
> @@ -48,9 +48,10 @@ static void sgx_sanitize_section(struct sgx_epc_section *section)
> struct sgx_epc_page, list);
>
> ret = __eremove(sgx_get_epc_virt_addr(page));
> - if (!ret)
> + if (!ret) {
> list_move(&page->list, §ion->page_list);
> - else
> + section->free_cnt += 1;
> + } else
> list_move_tail(&page->list, &dirty);
>
> spin_unlock(§ion->lock);
> @@ -646,7 +647,6 @@ static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size,
> list_add_tail(§ion->pages[i].list, §ion->init_laundry_list);
> }
>
> - section->free_cnt = nr_pages;
> return true;
> }
>
> --
> 2.19.1.3.ge56e4f7
>
>
prev parent reply other threads:[~2021-01-20 14:38 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-18 13:33 [PATCH] x86/sgx: Fix free_cnt counting logic in epc section Tianjia Zhang
2021-01-19 20:24 ` Sean Christopherson
2021-01-20 14:36 ` Jarkko Sakkinen [this message]
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