From: "Ard Biesheuvel" <ardb@kernel.org>
To: "Pankaj Gupta" <pankaj.gupta@amd.com>,
"Thomas Gleixner" <tglx@kernel.org>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
x86@kernel.org
Cc: "H . Peter Anvin" <hpa@zytor.com>,
"Tom Lendacky" <thomas.lendacky@amd.com>,
"Kiryl Shutsemau (Meta)" <kas@kernel.org>,
linux-kernel@vger.kernel.org, "Mike Rapoport" <rppt@kernel.org>,
linux-mm@kvack.org
Subject: Re: [PATCH] x86/unaccepted_memory: Do not accept ranges that are no longer E820 RAM
Date: Mon, 02 Nov 2026 13:11:54 +0100 [thread overview]
Message-ID: <deb5ea81-70bd-463d-8d98-ed51c316cf75@app.fastmail.com> (raw)
In-Reply-To: <f241f883-39f2-408b-9f44-574ce8d2910a@amd.com>
On Mon, 2 Nov 2026, at 13:01, Gupta, Pankaj wrote:
>>>>
>>> Can we just disallow memmap= when running in a confidential VM?
>>
>> My experiments showed: memmap itself don't have a problem but memap
>> with a hole is causing crash.
>>
>> There might be some usecases which are already using this, e.g:
>>
>> https://lore.kernel.org/all/20261029-cma-multi-v1-0-2cbced8b5cb7@kernel.org/
>>
>>
> Its also good to have a general safeguard to not accept memory that is
> not marked as RAM in e820?
>
Personally, I think all these command line hacks should be avoided in
confidential VMs, on the basis that the firmware's view of memory should
be in sync with the OS.
prev parent reply other threads:[~2026-11-02 12:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-02 11:31 Pankaj Gupta
2026-11-02 11:41 ` Ard Biesheuvel
2026-11-02 11:51 ` Gupta, Pankaj
2026-11-02 12:01 ` Gupta, Pankaj
2026-11-02 12:11 ` Ard Biesheuvel [this message]
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