[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] ACPI-Tables corrupted?
On 28/07/2010 12:26, "Juergen Gross" <juergen.gross@xxxxxxxxxxxxxx> wrote: > On 07/28/2010 12:03 PM, Keir Fraser wrote: >> On 28/07/2010 10:38, "Juergen Gross"<juergen.gross@xxxxxxxxxxxxxx> wrote: >> >>> As you can see, the DMAR eye-catcher is replaced by blanks! >>> This leads to a programmed panic in the crash kernel later in case of a >>> panic in dom0... >>> >>> Any ideas? >>> BTW: seen in unstable AND 4.0 >> >> Look at the tail of xen/drivers/passthrough/vtd/dmar.c: Xen *always* >> *unconditionally* trashes the DMAR so that dom0 will not parse it. >> Presumably bad stuff would happen if it did. > > As Dom0 is a pv-kernel, it should be able to ignore this entry. > The crash kernel OTOH should not panic due to the trashed entry! > What is the correct solution here? Could provide a cmdline option to not nobble the DMAR? > The crash kernel expects a valid DMAR entry, as following code in > enable_IR_x2apic() suggests: I don't know what that function does, nor how the error path below depends on DMAR. DMAR isn't mentioned in the below code. K. > /* IR is required if there is APIC ID > 255 even when running > * under KVM > */ > if (max_physical_apicid > 255 || !kvm_para_available()) { > if (max_physical_apicid > 255) { > pr_warning("NTR enable_IR_x2apic max_physical_apicid > > 255\n"); > } > if (!kvm_para_available()) { > pr_warning("NTR enable_IR_x2apic !kvm_para_available()\n"); > } > goto nox2apic; > } > > (kernel is 2.6.32.12 from Novell SLES11 SP1, the pr_warnings were added to > find the error path - it was the !kvm_para_available()) > > Looking closer to the code rises some doubts about correctness. The comment > at top seems not to be reflected by the following if... > > > Juergen _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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