On Tue, Jun 04, 2024 at 08:05:54PM +0200, Borislav Petkov wrote: > 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" Okay. > So this sentence above can go too, right? I don't think so. > 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... This kernel can't. But the next kernel can. If a page can be accessed via private mapping is determined by the presence in Secure EPT. This state persist across kexec. > > * 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... Crash kernel provides access to this memory via /proc/vmcore. Crash kernel will assume all memory there is private. > > * pr_err() may assist in understanding such crashes. > > "Print error info in order to leave bread crumbs for debugging." is what > I'd say. Okay. -- Kiryl Shutsemau / Kirill A. Shutemov _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
