From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Yosry Ahmed <yosryahmed@google.com>
Cc: x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Rick Edgecombe <rick.p.edgecombe@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] x86/mm: Fix LAM inconsistency during context switch
Date: Tue, 12 Mar 2024 14:35:46 +0200 [thread overview]
Message-ID: <3a56vovcqy7ju5og76nqlekfruq42i56wmp4oek3jgkffvzjby@q5guufebkpzr> (raw)
In-Reply-To: <20240312035951.3535980-2-yosryahmed@google.com>
On Tue, Mar 12, 2024 at 03:59:50AM +0000, Yosry Ahmed wrote:
> diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
> index 76e91fc68c5f3..748d2b3bdb985 100644
> --- a/arch/x86/kernel/process_64.c
> +++ b/arch/x86/kernel/process_64.c
> @@ -753,10 +753,12 @@ static long prctl_map_vdso(const struct vdso_image *image, unsigned long addr)
> static void enable_lam_func(void *__mm)
> {
> struct mm_struct *mm = __mm;
> + unsigned long lam = mm_lam_cr3_mask(mm);
> + u64 untag_mask = mm_untag_mask(mm);
>
Maybe push these mm dereferences inside the if block below?
I am not sure if compiler can re-order operations past this_cpu_read().
> if (this_cpu_read(cpu_tlbstate.loaded_mm) == mm) {
> - write_cr3(__read_cr3() | mm->context.lam_cr3_mask);
> - set_tlbstate_lam_mode(mm);
> + write_cr3(__read_cr3() | lam);
> + cpu_tlbstate_update_lam(lam, untag_mask);
> }
> }
>
--
Kiryl Shutsemau / Kirill A. Shutemov
next prev parent reply other threads:[~2024-03-12 12:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-12 3:59 [PATCH 1/3] x86/mm: Use IPIs to synchronize LAM enablement Yosry Ahmed
2024-03-12 3:59 ` [PATCH 2/3] x86/mm: Fix LAM inconsistency during context switch Yosry Ahmed
2024-03-12 12:35 ` Kirill A. Shutemov [this message]
2024-03-12 15:34 ` Yosry Ahmed
2024-03-12 3:59 ` [PATCH 3/3] x86/mm: Cleanup prctl_enable_tagged_addr() nr_bits error checking Yosry Ahmed
2024-03-12 12:36 ` Kirill A. Shutemov
2024-03-12 12:24 ` [PATCH 1/3] x86/mm: Use IPIs to synchronize LAM enablement Kirill A. Shutemov
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