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Date:   Wed, 15 Jun 2022 16:34:48 -0700
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Subject: Re: [PATCHv4 3/3] x86/tdx: Handle load_unaligned_zeropad() page-cross
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To:     "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
        luto@kernel.org, peterz@infradead.org
Cc:     ak@linux.intel.com, dan.j.williams@intel.com, david@redhat.com,
        hpa@zytor.com, linux-kernel@vger.kernel.org,
        sathyanarayanan.kuppuswamy@linux.intel.com, seanjc@google.com,
        thomas.lendacky@amd.com, x86@kernel.org
References: <20220614120135.14812-1-kirill.shutemov@linux.intel.com>
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From:   Dave Hansen <dave.hansen@intel.com>
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On 6/15/22 15:52, Kirill A. Shutemov wrote:
>> +	vaddr = (unsigned long)insn_get_addr_ref(&insn, regs);
>> +	if (vaddr / PAGE_SIZE != (vaddr + size) / PAGE_SIZE)
> Oops. I just realized it has off-by-one. It supposed to be:
> 
> 	if (vaddr / PAGE_SIZE != (vaddr + size - 1) / PAGE_SIZE)

That was bugging me.  Glad you caught this.

Wouldn't this be more obviously correct?

	if (ALIGN_DOWN(vaddr,        PAGE_SIZE) !=
	    ALIGN_DOWN(vaddr + size, PAGE_SIZE))
		...

I don't think we have a PAGE_ALIGN_DOWN().