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Date: Thu, 22 Feb 2024 12:50:11 +0200
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Ashish Kalra <Ashish.Kalra@amd.com>, tglx@linutronix.de, 
	mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, luto@kernel.org, 
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Subject: Re: [PATCH 2/2] x86/snp: Convert shared memory back to private on
 kexec
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References: <20240212104448.2589568-1-kirill.shutemov@linux.intel.com>
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 <97a7d69f-03e1-4ecc-a0ce-10bfe148509c@amd.com>
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In-Reply-To: <97a7d69f-03e1-4ecc-a0ce-10bfe148509c@amd.com>

On Wed, Feb 21, 2024 at 02:35:13PM -0600, Tom Lendacky wrote:
> > @@ -906,6 +917,206 @@ void snp_accept_memory(phys_addr_t start, phys_addr_t end)
> >   	set_pages_state(vaddr, npages, SNP_PAGE_STATE_PRIVATE);
> >   }
> > +static inline bool pte_decrypted(pte_t pte)
> > +{
> > +	return cc_mkdec(pte_val(pte)) == pte_val(pte);
> > +}
> > +
> 
> This is duplicated in TDX code, arch/x86/coco/tdx/tdx.c, looks like
> something that can go in a header file, maybe mem_encrypt.h.
> 

I think <asm/pgtable.h> is a better fit.

> > +void snp_kexec_stop_conversion(bool crash)
> > +{
> > +	/* Stop new private<->shared conversions */
> > +	conversion_allowed = false;
> > +	crash_requested = crash;
> > +
> > +	/*
> > +	 * Make sure conversion_allowed is cleared before checking
> > +	 * conversions_in_progress.
> > +	 */
> > +	barrier();
> 
> This should be smp_wmb().
> 

Why?

-- 
  Kiryl Shutsemau / Kirill A. Shutemov