On Wed, Dec 05, 2018 at 03:55:00PM +0100, Roger Pau Monne wrote:
> Current approximation of paging memory usage is based on the required
> amount when running in shadow mode and doesn't take into account the
> memory required by the IOMMU page tables.
>
> Fix this by introducing a function to calculate the amount of memory
> required by HAP/IOMMU page tables. The formula used to calculate such
> approximation is based on the pessimistic approach that each 4KB
> memory chunk will use 8 bytes of page table memory. Note that this
> approximation might need further tuning based on testing on different
> systems.
>
> Also fix the calculation of the required paging related memory in
> dom0_compute_nr_pages to take into account the paging implementation
> (shadow or HAP) and whether the IOMMU pages tables are shared with the
> HAP page tables.
>
> Signed-off-by: Roger Pau Monné <roger....@citrix.com>
> ---
> Cc: Jan Beulich <jbeul...@suse.com>
> Cc: Andrew Cooper <andrew.coop...@citrix.com>
> Cc: Wei Liu <wei.l...@citrix.com>
> Cc: andrei.seme...@bertin.fr
> ---
> xen/arch/x86/dom0_build.c | 31 +++++++++++++++++++++++++++----
> xen/arch/x86/hvm/dom0_build.c | 6 ++++--
> xen/include/asm-x86/dom0_build.h | 2 ++
> 3 files changed, 33 insertions(+), 6 deletions(-)
>
> diff --git a/xen/arch/x86/dom0_build.c b/xen/arch/x86/dom0_build.c
> index ba9aa85611..3a8e138f23 100644
> --- a/xen/arch/x86/dom0_build.c
> +++ b/xen/arch/x86/dom0_build.c
> @@ -267,6 +267,25 @@ unsigned long __init dom0_shadow_pages(const struct
> domain *d,
> return ((memkb + 1023) / 1024) << (20 - PAGE_SHIFT);
> }
>
> +unsigned long __init dom0_hap_pages(const struct domain *d,
> + unsigned long nr_pages)
> +{
> + /*
> + * Attempt to account for at least some of the MMIO regions by adding the
> + * size of the holes in the memory map to the amount of pages to map.
> Note
> + * this will obviously not account for MMIO regions that are past the
> last
> + * RAM range in the memory map.
> + */
> + nr_pages += max_page - total_pages;
Do those regions past end of RAM range show up in E820 map? If so, why
not just sum up all reserved regions?
Wei.
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