From: Borislav Petkov <bp@alien8.de>
To: Juergen Gross <jgross@suse.com>
Cc: "Jan Beulich" <jbeulich@suse.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
"Marek Marczykowski-Górecki" <marmarek@invisiblethingslab.com>,
xen-devel@lists.xenproject.org, x86@kernel.org,
linux-kernel@vger.kernel.org, "Mike Rapoport" <rppt@kernel.org>
Subject: Re: [PATCH] x86/setup: call early_reserve_memory() earlier
Date: Wed, 15 Sep 2021 13:00:20 +0200 [thread overview]
Message-ID: <YUHSRKubsGT2Jvur@zn.tnic> (raw)
In-Reply-To: <6cdc71dc-c26d-5c59-b7dd-0eb47ab9c861@suse.com>
You forgot to Cc Mike, lemme add him.
And drop stable@ too.
On Tue, Sep 14, 2021 at 01:06:22PM +0200, Juergen Gross wrote:
> On 14.09.21 12:03, Jan Beulich wrote:
> > On 14.09.2021 11:41, Juergen Gross wrote:
> > > Commit a799c2bd29d19c565 ("x86/setup: Consolidate early memory
> > > reservations") introduced early_reserve_memory() to do all needed
> > > initial memblock_reserve() calls in one function. Unfortunately the
> > > call of early_reserve_memory() is done too late for Xen dom0, as in
> > > some cases a Xen hook called by e820__memory_setup() will need those
> > > memory reservations to have happened already.
> > >
> > > Move the call of early_reserve_memory() to the beginning of
> > > setup_arch() in order to avoid such problems.
> > >
> > > Cc: stable@vger.kernel.org
> > > Fixes: a799c2bd29d19c565 ("x86/setup: Consolidate early memory reservations")
> > > Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
> > > Signed-off-by: Juergen Gross <jgross@suse.com>
> > > ---
> > > arch/x86/kernel/setup.c | 24 ++++++++++++------------
> > > 1 file changed, 12 insertions(+), 12 deletions(-)
> > >
> > > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> > > index 79f164141116..f369c51ec580 100644
> > > --- a/arch/x86/kernel/setup.c
> > > +++ b/arch/x86/kernel/setup.c
> > > @@ -757,6 +757,18 @@ dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
> > > void __init setup_arch(char **cmdline_p)
> > > {
> > > + /*
> > > + * Do some memory reservations *before* memory is added to
> > > + * memblock, so memblock allocations won't overwrite it.
> > > + * Do it after early param, so we could get (unlikely) panic from
> > > + * serial.
> >
> > Hmm, this part of the comment is not only stale now, but gets actively
> > undermined. No idea how likely such a panic() would be, and hence how
> > relevant it is to retain this particular property.
>
> Ah, right.
>
> The alternative would be to split it up again. Let's let the x86
> maintainers decide which way is the better one.
>
>
> Juergen
>
> >
> > Jan
> >
> > > + * After this point everything still needed from the boot loader or
> > > + * firmware or kernel text should be early reserved or marked not
> > > + * RAM in e820. All other memory is free game.
> > > + */
> > > + early_reserve_memory();
> > > +
> > > #ifdef CONFIG_X86_32
> > > memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data));
> > > @@ -876,18 +888,6 @@ void __init setup_arch(char **cmdline_p)
> > > parse_early_param();
> > > - /*
> > > - * Do some memory reservations *before* memory is added to
> > > - * memblock, so memblock allocations won't overwrite it.
> > > - * Do it after early param, so we could get (unlikely) panic from
> > > - * serial.
> > > - *
> > > - * After this point everything still needed from the boot loader or
> > > - * firmware or kernel text should be early reserved or marked not
> > > - * RAM in e820. All other memory is free game.
> > > - */
> > > - early_reserve_memory();
> > > -
> > > #ifdef CONFIG_MEMORY_HOTPLUG
> > > /*
> > > * Memory used by the kernel cannot be hot-removed because Linux
> > >
> >
>
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2021-09-15 11:00 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-14 9:41 [PATCH] x86/setup: call early_reserve_memory() earlier Juergen Gross
2021-09-14 10:03 ` Jan Beulich
2021-09-14 11:06 ` Juergen Gross
2021-09-15 11:00 ` Borislav Petkov [this message]
2021-09-16 9:09 ` Mike Rapoport
2021-09-16 10:29 ` Borislav Petkov
2021-09-16 10:31 ` Juergen Gross
2021-09-14 10:49 ` Marek Marczykowski-Górecki
2021-09-16 10:50 ` [tip: x86/urgent] x86/setup: Call " tip-bot2 for Juergen Gross
2021-09-19 16:55 ` Mike Galbraith
2021-09-19 17:04 ` Mike Rapoport
2021-09-20 0:56 ` Mike Galbraith
2021-09-20 9:26 ` Mike Rapoport
2021-09-20 9:38 ` Borislav Petkov
2021-09-20 11:25 ` Mike Galbraith
2021-09-20 11:33 ` Juergen Gross
2021-09-19 17:15 ` Borislav Petkov
2021-09-20 6:00 ` Juergen Gross
2021-09-20 9:46 ` Mike Rapoport
2021-09-20 22:48 ` Nathan Chancellor
2021-09-21 3:38 ` Borislav Petkov
2021-09-21 3:59 ` Nathan Chancellor
2021-09-21 7:36 ` Borislav Petkov
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