On 18.09.23 12:54, Ani Sinha wrote:
On Mon, Sep 18, 2023 at 3:49 PM David Hildenbrand <da...@redhat.com> wrote:
On 18.09.23 12:11, Ani Sinha wrote:
Ok hopefully my last question. I am still confused on something.
Does the above mean that the hole64 will actually start from an
address that is beyond maxram? Like basically if you added all of
ram_below_4G, ram_above_4G, hot plug_mem and pci_hole64 then can it
exceed maxram? I think it will. Does this not an issue?
If you'd have a 2 GiB VM, the device memory region and hole64 would
always be placed >= 4 GiB address, yes.
As maxram is just a size, and not a PFN, I don't think there is any
issue with that.
So this is all just a scheme to decide what to place where with maxram
amount of memory available. When the processor needs to access the
Yes. ram_size and maxram_size are only used to create the memory layout.
memory mapped PCI device, its simply dynamically mapped to the
available physical ram. Is my understanding correct here?
I'm no expert on that, but from my understanding that's what the
pci/pci64 hole is for -- mapping PCI BARs into these areas, such that
they don't conflict with actual guest RAM. That's why we still account
these "holes" as valid GFN that could be used+accessed by the VM once a
PCI BAR gets mapped in there.
--
Cheers,
David / dhildenb
