From: Dave Hansen <dave.hansen@intel.com>
To: Dan Williams <dan.j.williams@intel.com>, Kees Cook <kees@kernel.org>
Cc: dave.hansen@linux.intel.com,
Nikolay Borisov <nik.borisov@suse.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/3] devmem: Block mmap access when read/write access is restricted
Date: Fri, 11 Apr 2025 08:38:26 -0700 [thread overview]
Message-ID: <bf63b3e3-afdd-424c-87dc-f5488e770315@intel.com> (raw)
In-Reply-To: <67f8a1a15cc29_7205294d7@dwillia2-xfh.jf.intel.com.notmuch>
On 4/10/25 21:59, Dan Williams wrote:
>> I don't think we can just fail the mmap. 🙁
> For the TVM case the havoc of failing mmap for DMI info is smaller and
> the recommended fallback for /dev/mem being in accessible is
> /sys/firmware/dmi/tables. So I feel ok making TVMs take the modern
> replacement path which is what they would need to do anyway in the
> lockdown_kernel case. Tom, Dave, what do you think?
Yeah, doing the same as lockdown should be fine.
The other alternative to failing all mmap()s is to allow mmap(PROT_READ)
to succeed and then just map the zero page.
next prev parent reply other threads:[~2025-04-11 15:38 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-11 1:22 [PATCH v2 0/3] Restrict devmem for confidential VMs Dan Williams
2025-04-11 1:22 ` [PATCH v2 1/3] x86/devmem: Remove duplicate range_is_allowed() definition Dan Williams
2025-04-14 18:17 ` Naveen N Rao
2025-04-16 21:25 ` Dan Williams
2025-04-17 7:28 ` Naveen N Rao
2025-04-17 18:27 ` Dan Williams
2025-04-19 9:09 ` Naveen N Rao
2025-04-11 1:22 ` [PATCH v2 2/3] devmem: Block mmap access when read/write access is restricted Dan Williams
2025-04-11 2:32 ` Kees Cook
2025-04-11 4:59 ` Dan Williams
2025-04-11 15:38 ` Dave Hansen [this message]
2025-04-11 21:48 ` Dan Williams
2025-04-11 1:22 ` [PATCH v2 3/3] x86/devmem: Restrict /dev/mem access for potentially unaccepted memory by default Dan Williams
2025-04-14 18:22 ` Naveen N Rao
2025-04-16 21:30 ` Dan Williams
2025-04-14 10:56 ` [PATCH v2 0/3] Restrict devmem for confidential VMs Nikolay Borisov
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