Re: [PATCHv11.1 11/19] x86/tdx: Convert shared memory back to private on kexec
From: Borislav Petkov <bp@alien8.de>
Date: 2024-06-04 18:06:30
Also in:
kexec, linux-acpi, linux-coco, lkml
From: Borislav Petkov <bp@alien8.de>
Date: 2024-06-04 18:06:30
Also in:
kexec, linux-acpi, linux-coco, lkml
On Tue, Jun 04, 2024 at 07:14:00PM +0300, Kirill A. Shutemov wrote:
/* * If tdx_enc_status_changed() fails, it leaves memory * in an unknown state. If the memory remains shared, * it can result in an unrecoverable guest shutdown on * the first accessed through a private mapping.
"access" So this sentence above can go too, right? Because that comment is in tdx_kexec_finish() and we're basically going off to kexec. So can a guest even access it through a private mapping? We're shutting down so nothing is running anymore...
* The kdump kernel boot is not impacted as it uses * a pre-reserved memory range that is always private. * However, gathering crash information could lead to * a crash if it accesses unconverted memory through * a private mapping.
When does the kexec kernel even get such a private mapping? It is not even up yet...
* pr_err() may assist in understanding such crashes.
"Print error info in order to leave bread crumbs for debugging." is what
I'd say.
Thx.
--
Regards/Gruss,
Boris.
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