linux-kernel - Re: [PATCH v3 03/10] x86/tdx: Allow MMIO from userspace

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Message-ID: <ZsMxlu8_D4ZxFFqR@example.org>
Date: Mon, 19 Aug 2024 13:50:46 +0200
From: Alexey Gladkov <legion@...nel.org>
To: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc: linux-kernel@...r.kernel.org, linux-coco@...ts.linux.dev,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.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 v3 03/10] x86/tdx: Allow MMIO from userspace

On Mon, Aug 19, 2024 at 01:46:34PM +0300, Kirill A. Shutemov wrote:
> On Fri, Aug 16, 2024 at 03:43:53PM +0200, Alexey Gladkov wrote:
> > From: "Alexey Gladkov (Intel)" <legion@...nel.org>
> > 
> > The MMIO emulation is only allowed for kernel space code. It is carried
> > out through a special API, which uses only certain instructions.
> > 
> > This does not allow userspace to work with virtual devices.
> > 
> > Allow userspace to use the same instructions as kernel space to access
> > MMIO. So far, no additional checks have been made.
> > 
> > Signed-off-by: Alexey Gladkov (Intel) <legion@...nel.org>
> 
> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
> 
> And you seem to lost Reviewed-by from Thomas:
> 
> https://lore.kernel.org/all/874j867mnd.ffs@tglx

No. I removed it because the patch changed a lot after his review. I
didn't want to mislead anyone.

-- 
Rgrds, legion