[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] xen: switch to post-init routines in xen mmu.c earlier
On 11/12/14 05:32, Juergen Gross wrote: > On 12/10/2014 07:07 PM, David Vrabel wrote: >> On 10/12/14 15:56, Juergen Gross wrote: >>> With the virtual mapped linear p2m list the post-init mmu operations >>> must be used for setting up the p2m mappings, as in case of >>> CONFIG_FLATMEM the init routines may trigger BUGs. >>> >>> Reported-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> >>> Signed-off-by: Juergen Gross <jgross@xxxxxxxx> >>> --- >>> arch/x86/xen/mmu.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c >>> index 6ab6150..a1a429a 100644 >>> --- a/arch/x86/xen/mmu.c >>> +++ b/arch/x86/xen/mmu.c >>> @@ -1225,6 +1225,7 @@ static void __init xen_pagetable_p2m_setup(void) >>> static void __init xen_pagetable_init(void) >>> { >>> paging_init(); >>> + xen_post_allocator_init(); >>> >>> xen_pagetable_p2m_setup(); >>> >> >> This feels very chicken-and-egg to me: To setup the P2M we need to use >> the MMU ops that use the P2M... >> >> Please explain very clearly why this is all safe. > > Okay. paging_init() sets up all infrastructure needed to switch to the > post-init mmu ops done by xen_post_allocator_init(). With the virtual > mapped linear p2m list we need some mmu ops during setup of this list, > so we have to switch to the correct mmu ops as soon as possible. > > The p2m list is usable from the beginning, just expansion requires to > have established the new linear mapping. So the call of > xen_remap_memory() had to be introduced, but this is not due to the > mmu ops requiring this. > > Summing it up: calling xen_post_allocator_init() not directly after > paging_init() was conceptually wrong in the beginning, it just didn't > matter up to now as no functions used between the two calls needed > some critical mmu ops (e.g. alloc_pte). This has changed now, so I > corrected it. I've added this to the commit message and applied to devel/for-linus-3.19. If the tests pass I will consider sending a further pull request for 3.19 including the linear p2m changes early next week. Thanks. David _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |