linux-kernel - Re: [PATCH v3 1/4] x86/tdx: Add tdx_mcall

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Date:   Mon, 18 Apr 2022 20:53:39 -0700
From:   Sathyanarayanan Kuppuswamy 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>
To:     Kai Huang <kai.huang@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        Hans de Goede <hdegoede@...hat.com>,
        Mark Gross <mgross@...ux.intel.com>
Cc:     "H . Peter Anvin" <hpa@...or.com>,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
        Tony Luck <tony.luck@...el.com>,
        Andi Kleen <ak@...ux.intel.com>, linux-kernel@...r.kernel.org,
        platform-driver-x86@...r.kernel.org
Subject: Re: [PATCH v3 1/4] x86/tdx: Add tdx_mcall_tdreport() API support



On 4/18/22 8:51 PM, Kai Huang wrote:
>> Users are responsible to allocate aligned data. I don't think we need
>> to add a check for it. If it is unaligned, TDCALL will return error.
> Actually this is the kernel memory, but not user memory.  Otherwise
> virt_to_phys() doesn't make sense.  You copied the user data to kernel memory in
> the last patch.  So whether user memory is aligned doesn't matter, and in last
> patch, you have guaranteed the alignment is met during kernel memory allocation.

I mean't user of this API (not user space). But I agree with your
comments.

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer