linux-kernel - Re: [PATCH, RFC 51/62] iommu/vt-d: Support MKTME in DMA remapping

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190614120424.GJ3436@hirez.programming.kicks-ass.net>
Date:   Fri, 14 Jun 2019 14:04:24 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>, x86@...nel.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, Borislav Petkov <bp@...en8.de>,
        Andy Lutomirski <luto@...capital.net>,
        David Howells <dhowells@...hat.com>,
        Kees Cook <keescook@...omium.org>,
        Dave Hansen <dave.hansen@...el.com>,
        Kai Huang <kai.huang@...ux.intel.com>,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>,
        Alison Schofield <alison.schofield@...el.com>,
        linux-mm@...ck.org, kvm@...r.kernel.org, keyrings@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH, RFC 51/62] iommu/vt-d: Support MKTME in DMA remapping

On Wed, May 08, 2019 at 05:44:11PM +0300, Kirill A. Shutemov wrote:
> @@ -603,7 +605,12 @@ static inline void dma_clear_pte(struct dma_pte *pte)
>  static inline u64 dma_pte_addr(struct dma_pte *pte)
>  {
>  #ifdef CONFIG_64BIT
> -	return pte->val & VTD_PAGE_MASK;

I don't know this code, but going by the below cmpxchg64, this wants to
be READ_ONCE().

> +	u64 addr = pte->val;
> +	addr &= VTD_PAGE_MASK;
> +#ifdef CONFIG_X86_INTEL_MKTME
> +	addr &= ~mktme_keyid_mask;
> +#endif
> +	return addr;
>  #else
>  	/* Must have a full atomic 64-bit read */
>  	return  __cmpxchg64(&pte->val, 0ULL, 0ULL) & VTD_PAGE_MASK;
> -- 
> 2.20.1
>