linux-kernel - Re: [PATCH v1 1/4] x86/tdx: Split MMIO read and write operations

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <87a5hy7mvg.ffs@tglx>
Date: Tue, 30 Jul 2024 20:31:15 +0200
From: Thomas Gleixner <tglx@...utronix.de>
To: "Alexey Gladkov (Intel)" <legion@...nel.org>,
 linux-kernel@...r.kernel.org, linux-coco@...ts.linux.dev
Cc: Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, Dave
 Hansen <dave.hansen@...ux.intel.com>, "H. Peter Anvin" <hpa@...or.com>,
 "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>, Andrew Morton
 <akpm@...ux-foundation.org>, Yuan Yao <yuan.yao@...el.com>, Geert
 Uytterhoeven <geert@...ux-m68k.org>, Yuntao Wang <ytcoode@...il.com>, Kai
 Huang <kai.huang@...el.com>, Baoquan He <bhe@...hat.com>, Oleg Nesterov
 <oleg@...hat.com>, cho@...rosoft.com, decui@...rosoft.com,
 John.Starks@...rosoft.com
Subject: Re: [PATCH v1 1/4] x86/tdx: Split MMIO read and write operations

On Tue, Jul 30 2024 at 19:35, Alexey Gladkov wrote:
> To implement MMIO in userspace, additional memory checks need to be
> implemented. To avoid overly complicating the handle_mmio() function
> and to separate checks from actions, it will be split into two separate
> functions for handling read and write operations.

It will be split? The patch splits it, no?
>  
> +static int handle_mmio_write(struct insn *insn, enum insn_mmio_type mmio, int size,
> +		struct pt_regs *regs, struct ve_info *ve)

Please align the second line argument with the first argument in the
first line.

> +static int handle_mmio_read(struct insn *insn, enum insn_mmio_type mmio, int size,
> +		struct pt_regs *regs, struct ve_info *ve)
> +{
> +	unsigned long *reg, val;
> +	int extend_size;
> +	u8 extend_val = 0;

https://www.kernel.org/doc/html/latest/process/maintainer-tip.html#variable-declarations

>  static int handle_mmio(struct pt_regs *regs, struct ve_info *ve)
>  {
> -	unsigned long *reg, val, vaddr;
> +	unsigned long vaddr;
>  	char buffer[MAX_INSN_SIZE];
>  	enum insn_mmio_type mmio;
>  	struct insn insn = {};
> -	int size, extend_size;
> -	u8 extend_val = 0;
> +	int size;

Ditto

>  	/* Only in-kernel MMIO is supported */
>  	if (WARN_ON_ONCE(user_mode(regs)))
> @@ -428,12 +504,6 @@ static int handle_mmio(struct pt_regs *regs, struct ve_info *ve)
>  	if (WARN_ON_ONCE(mmio == INSN_MMIO_DECODE_FAILED))
>  		return -EINVAL;

Thanks,

        tglx