linux-kernel - Re: [PATCH] x86/tdx: Generate SIGBUS on userspace MMIO

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Message-ID: <b7bz3ix3yqmc5xla7ldnxu3lsvvqzlxigq2po2dqkoejucppj3@fbaw37ilwpkr>
Date: Mon, 10 Jun 2024 16:34:15 +0300
From: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To: 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>
Cc: linux-coco@...ts.linux.dev, linux-kernel@...r.kernel.org, 
	cho@...rosoft.com, decui@...rosoft.com, John.Starks@...rosoft.com
Subject: Re: [PATCH] x86/tdx: Generate SIGBUS on userspace MMIO

On Tue, May 28, 2024 at 01:09:19PM +0300, Kirill A. Shutemov wrote:
> Currently, attempting to perform MMIO from userspace in a TDX guest
> leads to a warning about an unexpected #VE and SIGSEGV being delivered
> to the process.
> 
> Enlightened userspace may choose to handle MMIO on their own if the
> kernel does not emulate it.
> 
> Handle the EPT_VIOLATION exit reason for userspace and deliver SIGBUS
> instead of SIGSEGV. SIGBUS is more appropriate for the MMIO situation.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>

Any feedback?

-- 
  Kiryl Shutsemau / Kirill A. Shutemov