linux-kernel - Re: [PATCH] x86/ldt: Fix support_pte_mask filtering in map_ldt

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Message-ID: <20180419145832.5mq3va53swswajmu@unicorn.suse.cz>
Date:   Thu, 19 Apr 2018 16:58:32 +0200
From:   Michal Kubecek <mkubecek@...e.cz>
To:     Joerg Roedel <joro@...tes.org>
Cc:     Borislav Petkov <bp@...e.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Peter Zijlstra <peterz@...radead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Joerg Roedel <jroedel@...e.de>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>
Subject: Re: [PATCH] x86/ldt: Fix support_pte_mask filtering in
 map_ldt_struct()

On Thu, Apr 19, 2018 at 04:11:34PM +0200, Joerg Roedel wrote:
> On Thu, Apr 19, 2018 at 03:00:11PM +0200, Borislav Petkov wrote:
> > fb43d6cb91ef x86/mm: Do not auto-massage page protections <--- NOT OK
> 
> Hmm, that hunk from above patch looks suspicious:
> 
> -               set_pgd(pgd + pgd_index(restore_jump_address), __pgd(__pa(pud) | _KERNPG_TABLE));
> +               pgd_t new_pgd = __pgd(__pa(p4d) | pgprot_val(pgtable_prot));
> +               set_pgd(pgd + pgd_index(restore_jump_address), new_pgd);
> 
> The old code used __pa(pud) while the new one uses __pa(p4d).
> 
> Boris, can you change that back to __pa(pud) and test please?

I had the same problem with v4.17-rc1 and fb43d6cb91ef and the change
you suggested applied on top of

  (a) fb43d6cb91ef with cherry-picked e6f39e87b643
  (b) current master (87ef12027b9b)

fixes the resume on my system.

Michal Kubecek