From: Dave Hansen <dave.hansen@intel.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
tglx@linutronix.de, mingo@redhat.com, bp@alien8.de
Cc: decui@microsoft.com, rick.p.edgecombe@intel.com,
sathyanarayanan.kuppuswamy@linux.intel.com, seanjc@google.com,
thomas.lendacky@amd.com, x86@kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCHv3 2/3] x86/tdx: Fix race between set_memory_encrypted() and load_unaligned_zeropad()
Date: Tue, 6 Jun 2023 11:14:29 -0700 [thread overview]
Message-ID: <f7f82377-6127-79e3-07d8-def490c4e35c@intel.com> (raw)
In-Reply-To: <20230606095622.1939-3-kirill.shutemov@linux.intel.com>
On 6/6/23 02:56, Kirill A. Shutemov wrote:
> load_unaligned_zeropad() can touch memory that is not owned by the
> caller, but just happened to next after the owned memory.
> This load_unaligned_zeropad() behaviour makes it important when kernel
> asks VMM to convert a GPA from shared to private or back. Kernel must
> never have a page mapped into direct mapping (and aliases) as private
> when the GPA is already converted to shared or when GPA is not yet
> converted to private.
>
> load_unaligned_zeropad() can touch memory that is not owned by the
> caller, but just happens to be next after the owned memory. This
> load_unaligned_zeropad() behavior makes it important when the kernel
> asks VMM to convert a GPA from shared to private or back. The kernel
> must never have a page mapped into direct mapping (and aliases) as
> private when the GPA is already converted to shared or when the GPA is
> not yet converted to private.
Heh, that must be really important info to have it in the changelog twice!
I'll fix it up when I apply it.
next prev parent reply other threads:[~2023-06-06 18:14 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-06 9:56 [PATCHv3 0/3] x86/tdx: Fix one more load_unaligned_zeropad() issue Kirill A. Shutemov
2023-06-06 9:56 ` [PATCHv3 1/3] x86/mm: Allow guest.enc_status_change_prepare() to fail Kirill A. Shutemov
2023-06-06 9:56 ` [PATCHv3 2/3] x86/tdx: Fix race between set_memory_encrypted() and load_unaligned_zeropad() Kirill A. Shutemov
2023-06-06 18:14 ` Dave Hansen [this message]
2023-06-06 18:37 ` Kirill A. Shutemov
2023-06-06 23:29 ` Dave Hansen
2023-06-07 11:16 ` Kirill A. Shutemov
2023-06-06 9:56 ` [PATCHv3 3/3] x86/mm: Fix enc_status_change_finish_noop() Kirill A. Shutemov
2023-07-06 16:48 ` [PATCHv3 0/3] x86/tdx: Fix one more load_unaligned_zeropad() issue Michael Kelley (LINUX)
2023-07-06 17:45 ` Dave Hansen
2023-07-07 14:06 ` Kirill A. Shutemov
2023-07-08 23:53 ` Michael Kelley (LINUX)
2023-07-09 6:09 ` Kirill A. Shutemov
2023-07-10 13:59 ` Tom Lendacky
2023-07-10 14:17 ` Michael Kelley (LINUX)
2023-07-13 14:43 ` Michael Kelley (LINUX)
2023-07-24 23:19 ` Kirill A. Shutemov
2023-07-25 15:51 ` Michael Kelley (LINUX)
2023-07-25 23:12 ` Kirill A. Shutemov
2023-07-26 3:15 ` Michael Kelley (LINUX)
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