From: Joerg Roedel <joro@8bytes.org>
To: Dave Hansen <dave.hansen@intel.com>
Cc: x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
hpa@zytor.com, Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Joerg Roedel <jroedel@suse.de>, Mike Rapoport <rppt@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Brijesh Singh <brijesh.singh@amd.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/4] x86/mm/64: Flush global TLB on AP bringup
Date: Thu, 30 Sep 2021 15:52:53 +0200 [thread overview]
Message-ID: <YVXBNeF8HZwtquE1@8bytes.org> (raw)
In-Reply-To: <9d1d3000-d4eb-eb6d-1a34-4b58fb0322e3@intel.com>
On Wed, Sep 29, 2021 at 08:09:38AM -0700, Dave Hansen wrote:
> On 9/29/21 7:54 AM, Joerg Roedel wrote:
>
> > + __flush_tlb_all();
> > }
>
> Is there a reason to do this flush here as opposed to doing it closer to
> the CR3 write where we switch away from trampoline_pgd? cr4_init()
> seems like an odd place.
Yeah, the reason is that global flushing is done by toggling CR4.PGE and
I didn't want to do that before CR4 is set up.
The CR3 switch away from the trampoline_pgd for secondary CPUs on x86-64
happens in head_64.S already. I will add some asm to do a global flush
there right after the CR3 switch. Secondary CPUs are already on kernel
virtual addresses at this point.
Joerg
next prev parent reply other threads:[~2021-09-30 13:53 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-29 14:54 [PATCH v2 0/4] x86/mm: Fix some issues with using trampoline_pgd Joerg Roedel
2021-09-29 14:54 ` [PATCH v2 1/4] x86/realmode: Add comment for Global bit usage in trampline_pgd Joerg Roedel
2021-09-29 14:54 ` [PATCH v2 2/4] x86/mm/64: Flush global TLB on AP bringup Joerg Roedel
2021-09-29 15:09 ` Dave Hansen
2021-09-30 13:52 ` Joerg Roedel [this message]
2021-09-29 14:55 ` [PATCH v2 3/4] x86/mm: Flush global TLB when switching to trampoline page-table Joerg Roedel
2021-09-29 15:07 ` Dave Hansen
2021-10-01 12:37 ` Joerg Roedel
2021-09-29 14:55 ` [PATCH v2 4/4] x86/64/mm: Map all kernel memory into trampoline_pgd Joerg Roedel
2021-09-29 15:22 ` Dave Hansen
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