On Wed, Jan 30, 2019 at 11:36:39AM +0100, Roger Pau Monne wrote:
> Due to the recent changes in the iommu mapping logic, the start
> addresses provided need to be aligned to the order intended to be
> mapped.
>
Can you reference some commits here? What would happen if the address is
not aligned?
> dom0 PVH domain builder didn't take this into account when populating
> the p2m, fix this by making sure the order is chosen so that the start
> address is aligned to it.
>
> 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>
> ---
> Without this patch trying to create a PVH dom0 will trigger an assert
> on certain hardware depending on the memory map.
> ---
> xen/arch/x86/hvm/dom0_build.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/xen/arch/x86/hvm/dom0_build.c b/xen/arch/x86/hvm/dom0_build.c
> index 51cf490811..a571d15c13 100644
> --- a/xen/arch/x86/hvm/dom0_build.c
> +++ b/xen/arch/x86/hvm/dom0_build.c
> @@ -152,6 +152,8 @@ static int __init pvh_populate_memory_range(struct domain
> *d,
>
> order = get_order_from_pages(end - start + 1);
> order = min(order ? order - 1 : 0, max_order);
> + /* The order allocated and populated must be aligned to the address.
> */
> + order = min(order, start ? find_first_set_bit(start) : MAX_ORDER);
Isn't max_order better here?
> page = alloc_domheap_pages(d, order, dom0_memflags | MEMF_no_scrub);
> if ( page == NULL )
> {
> --
> 2.20.1
>
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