On 04.10.2022 11:33, Roger Pau Monné wrote: > On Tue, Oct 04, 2022 at 10:06:36AM +0200, Jan Beulich wrote: >> On 30.09.2022 16:28, Roger Pau Monné wrote: >>> On Fri, Sep 30, 2022 at 09:50:40AM +0200, Jan Beulich wrote: >>>> efi_init_memory() in both relevant places is treating EFI_MEMORY_RUNTIME >>>> higher priority than the type of the range. To avoid accessing memory at >>>> runtime which was re-used for other purposes, make >>>> efi_arch_process_memory_map() follow suit. While on x86 in theory the >>>> same would apply to EfiACPIReclaimMemory, we don't actually "reclaim" >>>> E820_ACPI memory there and hence that type's handling can be left alone. >>> >>> What about dom0? Should it be translated to E820_RESERVED so that >>> dom0 doesn't try to use it either? >> >> I'm afraid I don't understand the questions. Not the least because I >> think "it" can't really mean "dom0" from the earlier sentence. > > Sorry, let me try again: > > The memory map provided to dom0 will contain E820_ACPI entries for > memory ranges with the EFI_MEMORY_RUNTIME attributes in the EFI memory > map. Is there a risk from dom0 reclaiming such E820_ACPI ranges, > overwriting the data needed for runtime services?
How would Dom0 go about doing so? It has no control over what we hand to the page allocator - it can only free pages which were actually allocated to it. E820_ACPI and E820_RESERVED pages are assigned to DomIO - Dom0 can map and access them, but it cannot free them. Jan
