On Tue, Mar 1, 2022 at 11:46 PM Marc Zyngier <maz@xxxxxxxxxx> wrote: > > On Fri, 25 Feb 2022 03:34:47 +0000, > Kalesh Singh <kaleshsingh@xxxxxxxxxx> wrote: > > > > pkvm_hyp_alloc_private_va_range() can be used to reserve private VA ranges > > in the pKVM nVHE hypervisor (). Also update __pkvm_create_private_mapping() > > to allow specifying an alignment for the private VA mapping. > > > > These will be used to implement stack guard pages for pKVM nVHE hypervisor > > (in a subsequent patch in the series). > > > > Credits to Quentin Perret <qperret@xxxxxxxxxx> for the idea of moving > > private VA allocation out of __pkvm_create_private_mapping() > > > > Signed-off-by: Kalesh Singh <kaleshsingh@xxxxxxxxxx> > > --- > > > > Changes in v4: > > - Handle null ptr in pkvm_alloc_private_va_range() and replace > > IS_ERR_OR_NULL checks in callers with IS_ERR checks, per Fuad > > - Fix kernel-doc comments format, per Fuad > > - Format __pkvm_create_private_mapping() prototype args (< 80 col), per Fuad > > > > Changes in v3: > > - Handle null ptr in IS_ERR_OR_NULL checks, per Mark > > > > Changes in v2: > > - Allow specifying an alignment for the private VA allocations, per Marc > > I probably badly expressed my earlier concern. > > Yes, an alignment is necessary. But how often do we want an alignment > that isn't naturally aligned to the size of the allocation (i.e. the > power of 2 >= the size of the allocation)? This is what the rest of > the kernel does (get_order() and co), and I thing we should follow > this. Hi Marc, Thanks for clarifying. I think making the alignment implicitly based on the size here will create unnecessary holes where PAGE_SIZE alignment would be ok and potentially overflow the private VA space earlier. Is it not a concern? - Kalesh > > This applies to both this patch and the previous one. > > Thanks, > > M. > > -- > Without deviation from the norm, progress is not possible. > > -- > To unsubscribe from this group and stop receiving emails from it, send an email to kernel-team+unsubscribe@xxxxxxxxxxx. > _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
